Co-reporter:Bo Shen, Adriana Mendoza-Garcia, Sarah E. Baker, Scott K. McCall, Chao Yu, Liheng Wu, and Shouheng Sun
Nano Letters September 13, 2017 Volume 17(Issue 9) pp:5695-5695
Publication Date(Web):August 3, 2017
DOI:10.1021/acs.nanolett.7b02593
We report a new strategy for stabilizing Fe nanoparticles (NPs) in the preparation of SmCo5–Fe nanocomposites. We coat the presynthesized Fe NPs with SiO2 and assemble the Fe/SiO2 NPs with Sm–Co–OH to form a mixture. After reductive annealing at 850 °C in the presence of Ca, we obtain SmCo5–Fe/SiO2 composites. Following aqueous NaOH washing and compaction, we produced exchange-coupled SmCo5–Fe nanocomposites with Fe NPs controlled at 12 nm. Our work demonstrates a successful strategy of stabilizing high moment magnetic NPs in a hard magnetic matrix to produce a nanocomposite with tunable magnetic properties.Keywords: compaction; Magnetic material; nanocomposite; nanoparticle stability; rare-earth hard magnet;
Co-reporter:Zheng Xi, Junrui Li, Dong Su, Michelle Muzzio, Chao Yu, Qing Li, and Shouheng Sun
Journal of the American Chemical Society October 25, 2017 Volume 139(Issue 42) pp:15191-15191
Publication Date(Web):October 5, 2017
DOI:10.1021/jacs.7b08643
Stabilizing a 3d-transition metal component M from an MPd alloy structure in an acidic environment is key to the enhancement of MPd catalysis for various reactions. Here we demonstrate a strategy to stabilize Cu in 5 nm CuPd nanoparticles (NPs) by coupling the CuPd NPs with perovskite-type WO2.72 nanorods (NRs). The CuPd NPs are prepared by controlled diffusion of Cu into Pd NPs, and the coupled CuPd/WO2.72 are synthesized by growing WO2.72 NRs in the presence of CuPd NPs. The CuPd/WO2.72 can stabilize Cu in 0.1 M HClO4 solution and, as a result, they show Cu, Pd composition dependent activity for the electrochemical oxidation of formic acid in 0.1 M HClO4 + 0.1 M HCOOH. Among three different CuPd/WO2.72 studied, the Cu48Pd52/WO2.72 is the most efficient catalyst, with its mass activity reaching 2086 mA/mgPd in a broad potential range of 0.40 to 0.80 V (vs RHE) and staying at this value after the 12 h chronoamperometry test at 0.40 V. The synthesis can be extended to obtain other MPd/WO2.72 (M = Fe, Co, Ni), making it possible to study MPd-WO2.72 interactions and MPd stabilization on enhancing MPd catalysis for various chemical reactions.
Co-reporter:Qing Li, Jiaju Fu, Wenlei Zhu, Zhengzheng Chen, Bo Shen, Liheng Wu, Zheng Xi, Tanyuan Wang, Gang Lu, Jun-jie Zhu, and Shouheng Sun
Journal of the American Chemical Society March 29, 2017 Volume 139(Issue 12) pp:4290-4290
Publication Date(Web):March 14, 2017
DOI:10.1021/jacs.7b00261
Tin (Sn) is known to be a good catalyst for electrochemical reduction of CO2 to formate in 0.5 M KHCO3. But when a thin layer of SnO2 is coated over Cu nanoparticles, the reduction becomes Sn-thickness dependent: the thicker (1.8 nm) shell shows Sn-like activity to generate formate whereas the thinner (0.8 nm) shell is selective to the formation of CO with the conversion Faradaic efficiency (FE) reaching 93% at −0.7 V (vs reversible hydrogen electrode (RHE)). Theoretical calculations suggest that the 0.8 nm SnO2 shell likely alloys with trace of Cu, causing the SnO2 lattice to be uniaxially compressed and favors the production of CO over formate. The report demonstrates a new strategy to tune NP catalyst selectivity for the electrochemical reduction of CO2 via the tunable core/shell structure.
Co-reporter:Chao Yu;Jiaju Fu;Michelle Muzzio;Tunli Shen;Junjie Zhu;Dong Su
Chemistry of Materials February 14, 2017 Volume 29(Issue 3) pp:1413-1418
Publication Date(Web):January 12, 2017
DOI:10.1021/acs.chemmater.6b05364
Co-reporter:Zheng Xi, Daniel P. Erdosy, Adriana Mendoza-Garcia, Paul N. Duchesne, Junrui Li, Michelle Muzzio, Qing Li, Peng Zhang, and Shouheng Sun
Nano Letters April 12, 2017 Volume 17(Issue 4) pp:2727-2727
Publication Date(Web):March 20, 2017
DOI:10.1021/acs.nanolett.7b00870
We synthesize a new type of hybrid Pd/WO2.72 structure with 5 nm Pd nanoparticles (NPs) anchored on 50 × 5 nm WO2.72 nanorods. The strong Pd/WO2.72 coupling results in the lattice expansion of Pd from 0.23 to 0.27 nm and the decrease of Pd surface electron density. As a result, the Pd/WO2.72 shows much enhanced catalysis toward electrochemical oxidation of formic acid in 0.1 M HClO4; it has a mass activity of ∼1600 mA/mgPd in a broad potential range of 0.4–0.85 V (vs RHE) and shows no obvious activity loss after a 12 h chronoamperometry test at 0.4 V. Our work demonstrates an important strategy to enhance Pd NP catalyst efficiency for energy conversion reactions.Keywords: electrocatalysis; formic acid oxidation; nanohybrids; Palladium; tungsten oxide;
Co-reporter:Zheng Xi;Haifeng Lv;Daniel P. Erdosy;Dong Su;Qing Li;Chao Yu;Junrui Li
Nanoscale (2009-Present) 2017 vol. 9(Issue 23) pp:7745-7749
Publication Date(Web):2017/06/14
DOI:10.1039/C7NR02711G
We report an electrochemical method to deposit atomic scale Pt on a 5 nm Au nanoparticle (NP) surface in N2-saturated 0.5 M H2SO4. Pt is provided by the Pt wire counter electrode via one-step Pt wire oxidation, dissolution, and deposition realized by controlled electrochemical scanning. Scanning from 0.6–1.0 V (vs. RHE) for 10 000 cycles gives Au98.2Pt1.8, which serves as an excellent catalyst for the formic acid oxidation reaction, showing 41 times higher specific activity (20.19 mA cm−2) and 25 times higher mass activity (10.80 A mgPt−1) with much better CO-tolerance and stability than commercial Pt. Our work demonstrates a unique strategy to minimize the use of Pt as a catalyst for electrochemical reactions.
Co-reporter:Weiwei Yang;Yongsheng Yu;Ying Tang;Keyun Li;Zheng Zhao;Menggang Li;Geping Yin;Haibo Li
Nanoscale (2009-Present) 2017 vol. 9(Issue 3) pp:1022-1027
Publication Date(Web):2017/01/19
DOI:10.1039/C6NR08507E
We synthesize dumbbell-like FePt–Fe3O4 nanoparticles (NPs) and study their electrocatalytic oxidation and sensing of dopamine (DA). The FePt and Fe3O4 NPs are strongly coupled in the dumbbell structure and as a result, the dumbbell FePt–Fe3O4 NPs show the best activity for DA oxidation with the DA detection limit reaching 1 nM. They are used successfully to monitor the DA concentration increase induced by K+-stimulation of PC12 cells. Our data show that an electrode modified with dumbbell-like FePt–Fe3O4 NPs can serve as the most sensitive probe for real-time quantitative detection of DA in a neurological environment.
Co-reporter:Zhong-Peng Lv;Tao Wang;Jing-Yuan Ge;Zhong-Zhi Luan;Di Wu;Jing-Lin Zuo
Journal of Materials Chemistry C 2017 vol. 5(Issue 29) pp:7200-7206
Publication Date(Web):2017/07/27
DOI:10.1039/C7TC01021D
We report a solution phase based assembly method to tune the transport mechanism and magnetoresistance (MR) of Fe3O4 nanoparticles (NPs). The NP topological arrangement is altered by the NP coating of tetrathiafulvalene carboxylic acid (TTFCOOH) or its dicarboxylic analogue (TTF(COOH)2). Consequently, the transport mechanism of the assembly switches from tunneling to Mott hopping. The MR ratios of the Fe3O4 NP assemblies can be further tuned by the polarity of the solvent used in the ligand exchange process. The TTF(COO)2-coated Fe3O4 NP assembly has a 5% room temperature MR ratio, which is the highest value among all TTF-COO-Fe3O4 NP assemblies reported so far.
Co-reporter:Zheng Xi, Adriana Mendoza-Garcia, Huiyuan Zhu, MiaoFang Chi, ... Shouheng Sun
Green Energy & Environment 2017 Volume 2, Issue 2(Volume 2, Issue 2) pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.gee.2017.01.001
NixWO2.72 nanorods (NRs) are synthesized by a one-pot reaction of Ni(acac)2 and WCl4. In the rod structure, Ni(II) intercalates in the defective perovskite-type WO2.72 and is stabilized. The NixWO2.72 NRs show the x-dependent electrocatalysis for the oxygen evolution reaction (OER) in 0.1 M KOH with Ni0.78WO2.72 being the most efficient, even outperforming the commercial Ir-catalyst. The synthesis is not limited to NixWO2.72 but can be extended to MxWO2.72 (M = Co, Fe) as well, providing a new class of oxide-based catalysts for efficient OER and other energy conversion reactions.Ni(II) is inserted into the defective perovskite-type WO2.72 nanorods and is stabilized to show Ni(II) composition dependent electrocatalysis with Ni0.78WO2.72 2being the most efficient catalyst, even outperforming the commercial Ir-catalyst, for the oxygen evolution reaction in 0.1 M KOH.Download high-res image (540KB)Download full-size image
Co-reporter:Liheng Wu, Adriana Mendoza-Garcia, Qing Li, and Shouheng Sun
Chemical Reviews 2016 Volume 116(Issue 18) pp:10473-10512
Publication Date(Web):June 29, 2016
DOI:10.1021/acs.chemrev.5b00687
In the past two decades, the synthetic development of magnetic nanoparticles (NPs) has been intensively explored for both fundamental scientific research and technological applications. Different from the bulk magnet, magnetic NPs exhibit unique magnetism, which enables the tuning of their magnetism by systematic nanoscale engineering. In this review, we first briefly discuss the fundamental features of magnetic NPs. We then summarize the synthesis of various magnetic NPs, including magnetic metal, metallic alloy, metal oxide, and multifunctional NPs. We focus on the organic phase syntheses of magnetic NPs with precise control over their sizes, shapes, compositions, and structures. Finally we discuss the applications of various magnetic NPs in sensitive diagnostics and therapeutics, high-density magnetic data recording and energy storage, as well as in highly efficient catalysis.
Co-reporter:Jie Yin, Qiaohui Fan, Yuxuan Li, Fangyi Cheng, Panpan Zhou, Pinxian Xi, and Shouheng Sun
Journal of the American Chemical Society 2016 Volume 138(Issue 44) pp:14546-14549
Publication Date(Web):October 24, 2016
DOI:10.1021/jacs.6b09351
We report a facile nitrogenation/exfoliation process to prepare hybrid Ni–C–N nanosheets. These nanosheets are <2 nm thin, chemically stable, and metallically conductive. They serve as a robust catalyst for the hydrogen evolution reaction in 0.5 M H2SO4, or 1.0 M KOH or 1.0 M PBS (pH = 7). For example, they catalyze the hydrogen evolution reaction in 0.5 M H2SO4 at an onset potential of 34.7 mV, an overpotential of 60.9 mV (at j = 10 mA cm–2) and with remarkable long-term stability (∼10% current drop after 70 h testing period). They are promising as a non-Pt catalyst for practical hydrogen evolution reaction.
Co-reporter:Adriana Mendoza-Garcia
Advanced Functional Materials 2016 Volume 26( Issue 22) pp:3809-3817
Publication Date(Web):
DOI:10.1002/adfm.201504172
One of the most active research areas in functional materials is the chemical synthesis of magnetic nanoparticles. Their potential in biomedical and technological applications has motivated the search for new forms of magnetic nanoparticles with additional chemical and physical functionalities. This review highlights recent advances in the high temperature solution-phase synthesis of monodisperse, multicomponent magnetic nanoparticles. Particular emphasis is put on iron-based metal, oxide, alloy and composite nanoparticles and their biomedical applications.
Co-reporter:Adriana Mendoza-Garcia, Dong Su and Shouheng Sun
Nanoscale 2016 vol. 8(Issue 6) pp:3244-3247
Publication Date(Web):15 Jan 2016
DOI:10.1039/C5NR08763E
Sea urchin-like (CoxFe1−x)2P shows Co/Fe-composition dependent catalysis for oxygen evolution reaction (OER) in 0.1 M KOH. The (Co0.54Fe0.46)2P is the most efficient OER catalyst, reaching 10 mA cm−2 at an overpotential of 0.37 V (vs. RHE). The report offers a new synergistic approach to tune and optimize the electrocatalysis of OER.
Co-reporter:Xiao Ren, Haitao Yang, Sai Gen, Jun Zhou, Tianzhong Yang, Xiangqun Zhang, Zhaohua Cheng and Shouheng Sun
Nanoscale 2016 vol. 8(Issue 2) pp:752-756
Publication Date(Web):26 Nov 2015
DOI:10.1039/C5NR06338H
Using reduced graphene oxide (rGO) as a template and high temperature sol–gel chemistry, we have prepared LaFeO3 nanoparticles (NPs). The 15 nm LaFeO3 NPs have a bandgap of 1.86 eV and the LaFeO3–rGO can function as an efficient catalyst for degradation of methylene blue (MB) or Rhodamine B (RhB) under visible-light irradiation with the electron transfer from the dye to hole dominating the oxidation process. The reported synthesis offers a general approach to perovskite-type NPs for efficient photocatalytic applications.
Co-reporter:Zhong-Peng Lv, Zhong-Zhi Luan, Pei-Yu Cai, Tao Wang, Cheng-Hui Li, Di Wu, Jing-Lin Zuo and Shouheng Sun
Nanoscale 2016 vol. 8(Issue 24) pp:12128-12133
Publication Date(Web):26 May 2016
DOI:10.1039/C6NR03311C
We report a facile approach to stabilize Fe3O4 nanoparticles (NPs) by using tetrathiafulvalene carboxylate (TTF-COO−) and to control electron transport with an enhanced magnetoresistance (MR) effect in TTF-COO–Fe3O4 NP assemblies. This TTF-COO-coating is advantageous over other conventional organic coatings, making it possible to develop stable Fe3O4 NP arrays for sensitive spintronics applications.
Co-reporter:Qing Li, Wenlei Zhu, Jiaju Fu, Hongyi Zhang, Gang Wu, Shouheng Sun
Nano Energy 2016 Volume 24() pp:1-9
Publication Date(Web):June 2016
DOI:10.1016/j.nanoen.2016.03.024
•Monodisperse Cu nanoparticles are synthesized and assembled on pyridinic-N rich graphene (p-NG).•7 nm Cu NPs assembled on p-NG are active and selective for electrochemical CO2 reduction to ethylene.•Standalone p-NG shows much higher activity than graphitic-N rich graphene and graphene oxide for CO2 reduction to formate.Monodisperse Cu nanoparticles (NPs) assembled on a pyridinic-N rich graphene (p-NG) support show a Cu NP mass- and size-dependent catalysis for the selective electrochemical reduction of CO2 to ethylene (C2H4). For the 7 nm Cu NPs assembled on the p-NG with the p-NG/Cu mass ratio of 1:1, the C2H4 formation Faradaic efficiency and hydrocarbon selectivity reach 19% and 79% respectively at −0.9 V (vs reversible hydrogen electrode). The p-NG itself can catalyze the CO2 reduction to formate, but in the composite p-NG-Cu structure, the pyridinic-N functions as a CO2 and proton absorber, facilitating hydrogenation and carbon–carbon coupling reactions on Cu for the formation of C2H4. The work demonstrates a new strategy to improve Cu NP catalytic activity and selectivity for the electrochemical reduction of CO2 for sustainable chemistry and energy applications.
Co-reporter:Qing Li, Shouheng Sun
Nano Energy 2016 Volume 29() pp:178-197
Publication Date(Web):November 2016
DOI:10.1016/j.nanoen.2016.02.030
•The fundamentals of the synthesis of monodisperse metal nanoparticles (MNPs) by organic solution phase reactions are outlined.•The common strategies applied to tailor MNP size, shape and structure (core/shell and intermetallic) are summarized.•The representative applications of MNPs in catalyzing oxygen reduction reaction, hydrogen evolution reaction, CO2 reduction reaction, methanol oxidation reaction, formic acid reaction and oxygen evolution reaction are highlighted.Metal nanoparticles (MNPs) are essential catalyst components in electrochemical energy conversion and storage devices, including fuel cells, Li-air batteries and water-splitting systems. Syntheses of monodisperse MNPs with controlled sizes, shapes and structures is key to fully harvesting their catalytic capabilities. This review first outlines the fundamentals of the synthesis of monodisperse MNPs by organic solution phase reactions. It then summaries common strategies applied to tailor MNP size, shape and structure. The review further highlights recent advances of using MNPs as efficient catalysts to catalyze some representative reactions that related to energy conversions, including oxygen reduction reaction, hydrogen evolution reaction, CO2 reduction reaction, methanol/formic acid oxidation reaction, and oxygen evolution reaction.
Co-reporter:Qing Li, Liheng Wu, Gang Wu, Dong Su, Haifeng Lv, Sen Zhang, Wenlei Zhu, Anix Casimir, Huiyuan Zhu, Adriana Mendoza-Garcia, and Shouheng Sun
Nano Letters 2015 Volume 15(Issue 4) pp:2468-2473
Publication Date(Web):February 27, 2015
DOI:10.1021/acs.nanolett.5b00320
Fully ordered face-centered tetragonal (fct) FePt nanoparticles (NPs) are synthesized by thermal annealing of the MgO-coated dumbbell-like FePt-Fe3O4 NPs followed by acid washing to remove MgO. These fct-FePt NPs show strong ferromagnetism with room temperature coercivity reaching 33 kOe. They serve as a robust electrocatalyst for the oxygen reduction reaction (ORR) in 0.1 M HClO4 and hydrogen evolution reaction (HER) in 0.5 M H2SO4 with much enhanced activity (the most active fct-structured alloy NP catalyst ever reported) and stability (no obvious Fe loss and NP degradation after 20 000 cycles between 0.6 and 1.0 V (vs RHE)). Our work demonstrates a reliable approach to FePt NPs with much improved fct-ordering and catalytic efficiency for ORR and HER.
Co-reporter:Haifeng Lv; Zheng Xi; Zhengzheng Chen; Shaojun Guo; Yongsheng Yu; Wenlei Zhu; Qing Li; Xu Zhang; Mu Pan; Gang Lu; Shichun Mu
Journal of the American Chemical Society 2015 Volume 137(Issue 18) pp:5859-5862
Publication Date(Web):April 30, 2015
DOI:10.1021/jacs.5b01100
We report a general approach to NiAu alloy nanoparticles (NPs) by co-reduction of Ni(acac)2 (acac = acetylacetonate) and HAuCl4·3H2O at 220 °C in the presence of oleylamine and oleic acid. Subject to potential cycling between 0.6 and 1.0 V (vs reversible hydrogen electrode) in 0.5 M H2SO4, the NiAu NPs are transformed into core/shell NiAu/Au NPs that show much enhanced catalysis for hydrogen evolution reaction (HER) with Pt-like activity and much robust durability. The first-principles calculations suggest that the high activity arises from the formation of Au sites with low coordination numbers around the shell. Our synthesis is not limited to NiAu but can be extended to FeAu and CoAu as well, providing a general approach to MAu/Au NPs as a class of new catalyst superior to Pt for water splitting and hydrogen generation.
Co-reporter:Liheng Wu, Bo Shen and Shouheng Sun
Nanoscale 2015 vol. 7(Issue 39) pp:16165-16169
Publication Date(Web):14 Sep 2015
DOI:10.1039/C5NR05291B
A facile organic-phase synthesis of monodisperse barium-doped iron oxide (Ba–Fe–O) nanoparticles (NPs) is reported. The Ba–Fe–O NPs can be converted into hexagonal barium ferrite NPs at 700 °C, showing strong ferromagnetic properties with Hc reaching 5260 Oe and Ms at 54 emu g−1. Moreover, the Ba–Fe–O NPs can be assembled into densely packed magnetic arrays, providing a unique model system for studying nanomagnetism and for nanomagnetic applications.
Co-reporter:Adriana Mendoza-Garcia;Dr. Huiyuan Zhu; Yongsheng Yu;Dr. Qing Li;Dr. Lin Zhou;Dr. Dong Su; Matthew J. Kramer; Shouheng Sun
Angewandte Chemie 2015 Volume 127( Issue 33) pp:9778-9781
Publication Date(Web):
DOI:10.1002/ange.201503386
Abstract
A facile approach to bimetallic phosphides, Co-Fe-P, by a high-temperature (300 °C) reaction between Co-Fe-O nanoparticles and trioctylphosphine is presented. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both the nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co0.54Fe0.46)2P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.
Co-reporter:Adriana Mendoza-Garcia;Dr. Huiyuan Zhu; Yongsheng Yu;Dr. Qing Li;Dr. Lin Zhou;Dr. Dong Su; Matthew J. Kramer; Shouheng Sun
Angewandte Chemie International Edition 2015 Volume 54( Issue 33) pp:9642-9645
Publication Date(Web):
DOI:10.1002/anie.201503386
Abstract
A facile approach to bimetallic phosphides, Co-Fe-P, by a high-temperature (300 °C) reaction between Co-Fe-O nanoparticles and trioctylphosphine is presented. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both the nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co0.54Fe0.46)2P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.
Co-reporter:Guangming Jiang, Huiyuan Zhu, Xu Zhang, Bo Shen, Liheng Wu, Sen Zhang, Gang Lu, Zhongbiao Wu, and Shouheng Sun
ACS Nano 2015 Volume 9(Issue 11) pp:11014
Publication Date(Web):October 4, 2015
DOI:10.1021/acsnano.5b04361
We report the synthesis of core/shell face-centered tetragonal (fct)-FePd/Pd nanoparticles (NPs) via reductive annealing of core/shell Pd/Fe3O4 NPs followed by temperature-controlled Fe etching in acetic acid. Among three different kinds of core/shell FePd/Pd NPs studied (FePd core at ∼8 nm and Pd shell at 0.27, 0.65, or 0.81 nm), the fct-FePd/Pd-0.65 NPs are the most efficient catalyst for the oxygen reduction reaction (ORR) in 0.1 M HClO4 with Pt-like activity and durability. This enhanced ORR catalysis arises from the desired Pd lattice compression in the 0.65 nm Pd shell induced by the fct-FePd core. Our study offers a general approach to enhance Pd catalysis in acid for ORR.Keywords: core/shell nanoparticles; electrocatalysis; face-centered tetragonal structure; FePd; oxygen reduction reaction;
Co-reporter:Zhong-Peng Lv, Zhong-Zhi Luan, Hai-Ying Wang, Sheng Liu, Cheng-Hui Li, Di Wu, Jing-Lin Zuo, and Shouheng Sun
ACS Nano 2015 Volume 9(Issue 12) pp:12205
Publication Date(Web):November 13, 2015
DOI:10.1021/acsnano.5b05444
We report a strategy to coat Fe3O4 nanoparticles (NPs) with tetrathiafulvalene-fused carboxylic ligands (TTF-COO−) and to control electron conduction and magnetoresistance (MR) within the NP assemblies. The TTF-COO-Fe3O4 NPs were prepared by replacing oleylamine (OA) from OA-coated 5.7 nm Fe3O4 NPs. In the TTF-COO-Fe3O4 NPs, the ligand binding density was controlled by the ligand size, and spin polarization on the Fe3O4 NPs was greatly improved. As a result, the interparticle spacing within the TTF-COO-Fe3O4 NP assemblies are readily controlled by the geometric length of TTF-based ligand. The shorter the distance and the better the conjugation between the TTF’s HOMO and LUMO, the higher the conductivity and MR of the assembly. The TTF-coating further stabilized the Fe3O4 NPs against deep oxidation and allowed I2-doping to increase electron conduction, making it possible to measure MR of the NP assembly at low temperature (<100 K). The TTF-COO-coating provides a viable way for producing stable magnetic Fe3O4 NP assemblies with controlled electron transport and MR for spintronics applications.Keywords: electron-conduction; Fe3O4 nanoparticles; magnetoresistance; spin transport; TTF;
Co-reporter:Yongsheng Yu, Weiwei Yang, Xiaolian Sun, Wenlei Zhu, X.-Z. Li, D. J. Sellmyer, and Shouheng Sun
Nano Letters 2014 Volume 14(Issue 5) pp:2778-2782
Publication Date(Web):April 1, 2014
DOI:10.1021/nl500776e
We report a simple, yet general, approach to monodisperse MPt (M = Fe, Co, Ni, Cu, Zn) nanoparticles (NPs) by coreduction of M(acac)2 and Pt(acac)2 (acac = acetylacetonate) with oleylamine at 300 °C. In the current reaction condition, oleylamine serves as the reducing agent, surfactant, and solvent. As an example, we describe in details the synthesis of 9.5 nm CoPt NPs with their compositions controlled from Co37Pt63 to Co69Pt31. These NPs show composition-dependent structural and magnetic properties. The unique oleylamine reduction process makes it possible to prepare MPt NPs with their physical properties and surface chemistry better rationalized for magnetic or catalytic applications.
Co-reporter:Liheng Wu, Pierre-Olivier Jubert, David Berman, Wayne Imaino, Alshakim Nelson, Huiyuan Zhu, Sen Zhang, and Shouheng Sun
Nano Letters 2014 Volume 14(Issue 6) pp:3395-3399
Publication Date(Web):May 6, 2014
DOI:10.1021/nl500904a
We report a facile synthesis of monodisperse ferrimagnetic CoxFe3–xO4 nanocubes (NCs) through thermal decomposition of Fe(acac)3 and Co(acac)2 (acac = acetylacetonate) in the presence of oleic acid and sodium oleate. The sizes of the NCs are tuned from 10 to 60 nm, and their composition is optimized at x = 0.6 to show strong ferrimagnetism with the 20 nm Co0.6Fe2.4O4 NCs showing a room temperature Hc of 1930 Oe. The ferrimagnetic NCs are self-assembled at the water–air interface into a large-area (in square centimeter) monolayer array with a high packing density and (100) texture. The 20 nm NC array can be recorded at linear densities ranging from 254 to 31 kfci (thousand flux changes per inch). The work demonstrates the great potential of solution-phase synthesis and self-assembly of magnetic array for magnetic recording applications.
Co-reporter:Shaojun Guo ; Xu Zhang ; Wenlei Zhu ; Kai He ; Dong Su ; Adriana Mendoza-Garcia ; Sally Fae Ho ; Gang Lu
Journal of the American Chemical Society 2014 Volume 136(Issue 42) pp:15026-15033
Publication Date(Web):October 3, 2014
DOI:10.1021/ja508256g
Controlling the electronic structure and surface strain of a nanoparticle catalyst has become an important strategy to tune and to optimize its catalytic efficiency for a chemical reaction. Using density functional theory (DFT) calculations, we predicted that core/shell M/CuPd (M = Ag, Au) NPs with a 0.8 or 1.2 nm CuPd2 shell have similar but optimal surface strain and composition and may surpass Pt in catalyzing oxygen reduction reactions. We synthesized monodisperse M/CuPd NPs by the coreduction of palladium acetylacetonate and copper acetylacetonate in the presence of Ag (or Au) nanoparticles with controlled shell thicknesses of 0.4, 0.75, and 1.1 nm and CuPd compositions and evaluated their catalysis for the oxygen reduction reaction in 0.1 M KOH solution. As predicted, our Ag/Cu37Pd63 and Au/Cu40Pd60 catalysts with 0.75 and 1.1 nm shells were more efficient catalysts than the commercial Pt catalyst (Fuel Cells Store), with their mass activity reaching 0.20 A/mg of noble metal at −0.1 V vs Ag/AgCl (4 M KCl); this was over 3 times higher than that (0.06 A/mg Pt) from the commercial Pt. These Ag(Au)/CuPd nanoparticles are promising non-Pt catalysts for oxygen reduction reactions.
Co-reporter:Wenlei Zhu ; Yin-Jia Zhang ; Hongyi Zhang ; Haifeng Lv ; Qing Li ; Ronald Michalsky ; Andrew A. Peterson
Journal of the American Chemical Society 2014 Volume 136(Issue 46) pp:16132-16135
Publication Date(Web):November 7, 2014
DOI:10.1021/ja5095099
In this communication, we show that ultrathin Au nanowires (NWs) with dominant edge sites on their surface are active and selective for electrochemical reduction of CO2 to CO. We first develop a facile seed-mediated growth method to synthesize these ultrathin (2 nm wide) Au NWs in high yield (95%) by reducing HAuCl4 in the presence of 2 nm Au nanoparticles (NPs). These NWs catalyze CO2 reduction to CO in aqueous 0.5 M KHCO3 at an onset potential of −0.2 V (vs reversible hydrogen electrode). At −0.35 V, the reduction Faradaic efficiency (FE) reaches 94% (mass activity 1.84 A/g Au) and stays at this level for 6 h without any noticeable activity change. Density functional theory (DFT) calculations suggest that the excellent catalytic performance of these Au NWs is attributed both to their high mass density of reactive edge sites (≥16%) and to the weak CO binding on these sites. These ultrathin Au NWs are the most efficient nanocatalyst ever reported for electrochemical reduction of CO2 to CO.
Co-reporter:Xiaolian Sun ; Dongguo Li ; Yong Ding ; Wenlei Zhu ; Shaojun Guo ; Zhong Lin Wang
Journal of the American Chemical Society 2014 Volume 136(Issue 15) pp:5745-5749
Publication Date(Web):March 20, 2014
DOI:10.1021/ja500590n
We report a facile synthesis of monodisperse core/shell 5/1.5 nm Au/CuPt nanoparticles by coreduction of platinum acetylacetonate and copper acetylacetonate in the presence of 5 nm Au nanoparticles. The CuPt alloy effect and core/shell interactions make these Au/CuPt nanoparticles a promising catalyst for both oxygen reduction reaction and methanol oxidation reaction in 0.1 M HClO4 solution. Their specific (mass) reduction and oxidation activities reach 2.72 mA/cm2 (1500 mA/mg Pt) at 0.9 V and 0.755 mA/cm2 (441 mA/mg Pt) at 0.8 V (vs reversible hydrogen electrode), respectively. Our studies show that the existence of the Au nanoparticle core not only minimizes the Pt usage but also improves the stability of the Au/CuPt catalyst for fuel cell reactions. The results suggest that the core/shell design is indeed effective for optimizing nanoparticle catalysis. The same concept may be extended to other multimetallic nanoparticle systems, making it possible to tune nanoparticle catalysis for many different chemical reactions.
Co-reporter:Sen Zhang ; Xu Zhang ; Guangming Jiang ; Huiyuan Zhu ; Shaojun Guo ; Dong Su ; Gang Lu
Journal of the American Chemical Society 2014 Volume 136(Issue 21) pp:7734-7739
Publication Date(Web):May 6, 2014
DOI:10.1021/ja5030172
Controlling nanoparticle (NP) surface strain, i.e. compression (or stretch) of surface atoms, is an important approach to tune NP surface chemistry and to optimize NP catalysis for chemical reactions. Here we show that surface Pt strain in the core/shell FePt/Pt NPs with Pt in three atomic layers can be rationally tuned via core structural transition from cubic solid solution [denoted as face centered cubic (fcc)] structure to tetragonal intermetallic [denoted as face centered tetragonal (fct)] structure. The high activity observed from the fct-FePt/Pt NPs for oxygen reduction reaction (ORR) is due to the release of the overcompressed Pt strain by the fct-FePt as suggested by quantum mechanics–molecular mechanics (QM–MM) simulations. The Pt strain effect on ORR can be further optimized when Fe in FePt is partially replaced by Cu. As a result, the fct-FeCuPt/Pt NPs become the most efficient catalyst for ORR and are nearly 10 times more active in specific activity than the commercial Pt catalyst. This structure-induced surface strain control opens up a new path to tune and optimize NP catalysis for ORR and many other chemical reactions.
Co-reporter:Haydar Göksu, Sally Fae Ho, Önder Metin, Katip Korkmaz, Adriana Mendoza Garcia, Mehmet Serdar Gültekin, and Shouheng Sun
ACS Catalysis 2014 Volume 4(Issue 6) pp:1777
Publication Date(Web):April 23, 2014
DOI:10.1021/cs500167k
We report a facile synthesis of monodisperse NiPd alloy nanoparticles (NPs) and their assembly on graphene (G) to catalyze the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of R-NO2 and/or R-CN to R-NH2 in aqueous methanol solutions at room temperature. The 3.4 nm NiPd alloy NPs were prepared by coreduction of nickel(II) acetate and palladium(II) acetlyacetonate by borane-tert-butylamine in oleylamine and deposition on G via a solution phase self-assembly process. G-NiPd showed composition-dependent catalysis on the tandem reaction with G-Ni30Pd70 being the most active. A variety of R-NO2 and/or R-CN derivatives were reduced selectively into R-NH2 via G-Ni30Pd70 catalyzed tandem reaction in 5–30 min reaction time with the conversion yields reaching up to 100%. Our study demonstrates a new approach to G-NiPd-catalyzed dehydrogenation of AB and hydrogenation of R-NO2 and R-CN. The G-NiPd NP catalyst is efficient and reusable, and the reaction can be performed in an environment-friendly process with short reaction times and high yields.Keywords: alloy nanoparticles; dehydrogenation; hydrogenation; nitro/nitrile compounds; primary amines; tandem reaction
Co-reporter:Sally Fae Ho, Adriana Mendoza-Garcia, Shaojun Guo, Kai He, Dong Su, Sheng Liu, Önder Metin and Shouheng Sun
Nanoscale 2014 vol. 6(Issue 12) pp:6970-6973
Publication Date(Web):15 Apr 2014
DOI:10.1039/C4NR01107D
MPd (M = Co, or Cu) nanoparticles (NPs) were synthesized by borane–amine reduction of metal acetylacetonates. The size of the MPd NPs was controlled at 3.5 nm and their compositions were tuned by the molar ratios of the metal precursors. These MPd NPs were active catalysts for electrochemical oxidation of formic acid and the Cu30Pd70 NPs showed the highest mass activity at 1192.9 A gPd−1, much higher than 552.6 A gPd−1 obtained from the 3.5 nm Pd NPs. Our synthesis provides a facile route to MPd NPs, allowing further investigation of MPd NP catalysts for electrochemical oxidation and many other chemical reactions.
Co-reporter:Sen Zhang, Guangming Jiang, Gabriel T. Filsinger, Liheng Wu, Huiyuan Zhu, Jonghun Lee, Zhongbiao Wu and Shouheng Sun
Nanoscale 2014 vol. 6(Issue 9) pp:4852-4856
Publication Date(Web):21 Feb 2014
DOI:10.1039/C4NR00193A
We report a facile halide ion (Cl− or Br−) mediated synthesis of Fe nanoparticles (NPs) by thermal decomposition of Fe(CO)5. The NP structure is controlled to be either amorphous (in the absence of halide ions) or single crystalline bcc (in the presence of halide ions). Through systematic investigation on the synthetic conditions, we have confirmed that the formation of bcc-Fe NPs is facilitated by the strong interactions between halide ions and Fe, which favor thermodynamic growth of Fe over the existing Fe NPs. Compared with the amorphous Fe NPs, the bcc-Fe NPs exhibit much enhanced magnetization values and chemical stability. This halide ion mediated growth may become a general strategy to control the growth of metallic NPs, especially first-row transition metal NPs, in a thermodynamically more stable way, producing single crystalline NPs with much controlled physical and chemical properties for magnetic and catalytic applications.
Co-reporter:Huiyuan Zhu;Aruna Sigdel;Dr. Sen Zhang;Dr. Dong Su;Zheng Xi;Dr. Qing Li; Shouheng Sun
Angewandte Chemie 2014 Volume 126( Issue 46) pp:12716-12720
Publication Date(Web):
DOI:10.1002/ange.201406281
Abstract
Monodisperse 5 nm AuMn nanoparticles were synthesized by hydride reduction of manganese acetylacetonate in the presence of Au nanoparticles. The alloy was formed through fast Mn diffusion into the Au structure. The AuMn nanoparticles were converted to Au-MnO composite particles through air annealing at 170 °C. These Au-MnO particles, especially the core/shell Au/MnO nanoparticles, were active for the electrochemical reduction of H2O2, with a detection limit reaching 8 nM. This highly sensitive electrochemical sensor based on the Au/MnO nanoparticles was used to monitor H2O2 concentrations released from living cells, from which tumorigenic cells were discovered to release higher levels of H2O2 than the non-tumorigenic cells.
Co-reporter:Huiyuan Zhu;Aruna Sigdel;Dr. Sen Zhang;Dr. Dong Su;Zheng Xi;Dr. Qing Li; Shouheng Sun
Angewandte Chemie International Edition 2014 Volume 53( Issue 46) pp:12508-12512
Publication Date(Web):
DOI:10.1002/anie.201406281
Abstract
Monodisperse 5 nm AuMn nanoparticles were synthesized by hydride reduction of manganese acetylacetonate in the presence of Au nanoparticles. The alloy was formed through fast Mn diffusion into the Au structure. The AuMn nanoparticles were converted to Au-MnO composite particles through air annealing at 170 °C. These Au-MnO particles, especially the core/shell Au/MnO nanoparticles, were active for the electrochemical reduction of H2O2, with a detection limit reaching 8 nM. This highly sensitive electrochemical sensor based on the Au/MnO nanoparticles was used to monitor H2O2 concentrations released from living cells, from which tumorigenic cells were discovered to release higher levels of H2O2 than the non-tumorigenic cells.
Co-reporter:Fei Liu;Jinghan Zhu;Wenlong Yang;Yunhe Dong; Yanglong Hou;Chenzhen Zhang;Han Yin; Shouheng Sun
Angewandte Chemie International Edition 2014 Volume 53( Issue 8) pp:2176-2180
Publication Date(Web):
DOI:10.1002/anie.201309723
Abstract
Controlling exchange coupling between hard magnetic and soft magnetic phases is the key to the fabrication of advanced magnets with tunable magnetism and high energy density. Using FePt as an example, control over the magnetism in exchange-coupled nanocomposites of hard magnetic face-centered tetragonal (fct) FePt and soft magnetic Co (or Ni, Fe2C) is shown. The dispersible hard magnetic fct-FePt nanoparticles are first prepared with their coercivity (Hc) reaching 33 kOe. Then core/shell fct-FePt/Co (or Ni, Fe2C) nanoparticles are synthesized by reductive thermal decomposition of the proper metal precursors in the presence of fct-FePt nanoparticles. These core/shell nanoparticles are strongly coupled by exchange interactions and their magnetic properties can be rationally tuned by the shell thickness of the soft phase. This work provides an ideal model system for the study of exchange coupling at the nanoscale, which will be essential for building superstrong magnets for various permanent magnet applications in the future.
Co-reporter:Shouheng Sun
Journal of Inorganic and Organometallic Polymers and Materials 2014 Volume 24( Issue 1) pp:33-38
Publication Date(Web):2014 January
DOI:10.1007/s10904-013-9975-x
This short tutorial review highlights the advance in high temperature solution phase chemical synthesis of monodisperse magnetic nanoparticles (MNPs), especially iron oxide NPs, as contrast enhancement agents for cancer detection by magnetic resonance imaging (MRI). It introduces briefly the unique nanomagnetism of MNPs required for MRI. It then summarizes some typical methods used to prepare monodisperse Fe3O4 and ferrite MFe2O4 MNPs from high temperature organic phase reaction with controlled magnetic properties. It further outlines the chemistry used to make these MNPs biocompatible and target-specific. Finally it presents two examples to demonstrate the MNP control achieved from chemical synthesis for sensitive detection of cancer.
Co-reporter:Qing Li, Nasir Mahmood, Jinghan Zhu, Yanglong Hou, Shouheng Sun
Nano Today 2014 Volume 9(Issue 5) pp:668-683
Publication Date(Web):October 2014
DOI:10.1016/j.nantod.2014.09.002
•The new chemistry used to synthesize high quality graphene, especially liquid phase exfoliation (LPE), is highlighted.•The methodologies developed to dope graphene with heteroatoms to modify and control graphene properties are outlined.•The general approaches to prepare graphene–nanoparticle composites are presented.•The applications of graphene-based nanocomposites in electrochemical energy storage (lithium based batteries and supercapacitors) and conversion devices (fuel cells and electrolyzers) are summarized.Graphene is a two dimensional (2D) planar and hexagonal array of carbon atoms and has been studied extensively as advanced nanomaterials for important technological applications. This review summarizes the recent developments in chemistry, materials and energy applications of graphene, doped graphene and their composites with nanoparticles (NPs). It first highlights the new chemistry used to synthesize high quality graphene. It then outlines the methodologies developed to dope graphene with heteroatoms to modify and control graphene properties. It further describes the general approaches to graphene–NP composites via either direct NP growth onto graphene or self-assembly of the pre-formed NPs on graphene surface. These graphene–NP composites provide some ideal systems for studying synergistic effects between graphene and NPs on catalysis. The review focuses on applications of graphene–NP composites in increasing electrochemical energy storage density and in catalyzing chemical reactions with much desired electrochemical efficiencies.
Co-reporter:Yongsheng Yu;Adriana Mendoza-Garcia;Bo Ning
Advanced Materials 2013 Volume 25( Issue 22) pp:3090-3094
Publication Date(Web):
DOI:10.1002/adma.201300595
Co-reporter:Xiaolian Sun;Shaojun Guo;Chun-Shiang Chung;Wenlei Zhu
Advanced Materials 2013 Volume 25( Issue 1) pp:132-136
Publication Date(Web):
DOI:10.1002/adma.201203218
Co-reporter:Yongsheng Yu, Kewei Sun, Yuan Tian, X.-Z. Li, M. J. Kramer, D. J. Sellmyer, J. E. Shield, and Shouheng Sun
Nano Letters 2013 Volume 13(Issue 10) pp:4975-4979
Publication Date(Web):September 16, 2013
DOI:10.1021/nl403043d
We report a one-pot synthesis of urchin-like FePd–Fe3O4 nanocomposites, spherical clusters of FePd nanoparticles (NPs) with spikes of Fe3O4 nanorods (NRs), via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(acac)2. The FePd NPs with sizes between 6 and 9 nm self-aggregate into 60 nm superparticles (SPs), and Fe3O4 NRs grow on the surface of these SPs. Reductive annealing at 500 °C converts the FePd–Fe3O4 into exchange-coupled nanocomposites L10–FePd–Fe with their Hc tunable from 0.8 to 2.6 kOe and Ms controlled from 90 to 190 emu/g. The work provides a general approach to L10–FePd–Fe nanocomposite magnets for understanding exchange coupling at the nanoscale. The concept may be extended to other magnetic nanocomposite systems and may help to build superstrong magnets for magnetic applications.
Co-reporter:Huiyuan Zhu, Sen Zhang, Yu-Xi Huang, Liheng Wu, and Shouheng Sun
Nano Letters 2013 Volume 13(Issue 6) pp:2947-2951
Publication Date(Web):May 7, 2013
DOI:10.1021/nl401325u
Sub-10 nm nanoparticles (NPs) of M(II)-substituted magnetite MxFe3–xO4 (MxFe1–xO•Fe2O3) (M = Mn, Fe, Co, Cu) were synthesized and studied as electrocatalysts for oxygen reduction reaction (ORR) in 0.1 M KOH solution. Loaded on commercial carbon support, these MxFe3–xO4 NPs showed the M(II)-dependent ORR catalytic activities with MnxFe3–xO4 being the most active followed by CoxFe3–xO4, CuxFe3–xO4, and Fe3O4. The ORR activity of the MnxFe3–xO4 was further tuned by controlling x and MnFe2O4 NPs were found to be as efficient as the commercial Pt in catalyzing ORR. The MnFe2O4 NPs represent a new class of highly efficient non-Pt catalyst for ORR in alkaline media.
Co-reporter:Shaojun Guo ; Sen Zhang ; Dong Su
Journal of the American Chemical Society 2013 Volume 135(Issue 37) pp:13879-13884
Publication Date(Web):August 26, 2013
DOI:10.1021/ja406091p
We report a new seed-mediated growth of FePt over 2.5 nm wide FePtM (M = Pd, Au) nanowires (NWs) into core/shell FePtM/FePt NWs with controlled FePt shell thickness from 0.3 to 1.3 nm. These FePtM/FePt NWs show shell thickness and core composition-dependent electrocatalytic activity for oxygen reduction reaction (ORR) in 0.1 M HClO4. These core/shell FePtM/FePt NWs are generally more active and durable than the corresponding alloy NWs. Among FePtM/FePt NWs, FePt NWs, FePtPd NWs, and commercial Pt studied, the FePtPd/FePt NWs (0.8 nm shell) show the specific activity of 3.47 mA·cm–2 and the mass activity of 1.68 A/mg Pt at 0.5 V (vs. Ag/AgCl), superior to all other NWs (less than 1.59 mA/cm2 and 0.82 A/mg Pt for FePtAu/FePt and FePt) as well as the commercial Pt (0.24 mA/cm2 and 0.141 A/mg Pt). The FePtM/FePt (0.8 nm shell) NWs are also stable in the ORR condition and show no activity decrease after 5000 potential sweeps between 0.4 and 0.8 V (vs Ag/AgCl). They are the most efficient nanocatalyst ever reported for ORR.
Co-reporter:Wenlei Zhu ; Ronald Michalsky ; Önder Metin ; Haifeng Lv ; Shaojun Guo ; Christopher J. Wright ; Xiaolian Sun ; Andrew A. Peterson
Journal of the American Chemical Society 2013 Volume 135(Issue 45) pp:16833-16836
Publication Date(Web):October 24, 2013
DOI:10.1021/ja409445p
We report selective electrocatalytic reduction of carbon dioxide to carbon monoxide on gold nanoparticles (NPs) in 0.5 M KHCO3 at 25 °C. Among monodisperse 4, 6, 8, and 10 nm NPs tested, the 8 nm Au NPs show the maximum Faradaic efficiency (FE) (up to 90% at −0.67 V vs reversible hydrogen electrode, RHE). Density functional theory calculations suggest that more edge sites (active for CO evolution) than corner sites (active for the competitive H2 evolution reaction) on the Au NP surface facilitates the stabilization of the reduction intermediates, such as COOH*, and the formation of CO. This mechanism is further supported by the fact that Au NPs embedded in a matrix of butyl-3-methylimidazolium hexafluorophosphate for more efficient COOH* stabilization exhibit even higher reaction activity (3 A/g mass activity) and selectivity (97% FE) at −0.52 V (vs RHE). The work demonstrates the great potentials of using monodisperse Au NPs to optimize the available reaction intermediate binding sites for efficient and selective electrocatalytic reduction of CO2 to CO.
Co-reporter:Huiyuan Zhu ; Sen Zhang ; Shaojun Guo ; Dong Su
Journal of the American Chemical Society 2013 Volume 135(Issue 19) pp:7130-7133
Publication Date(Web):May 1, 2013
DOI:10.1021/ja403041g
To further enhance the catalytic activity and durability of nanocatalysts for the oxygen reduction reaction (ORR), we synthesized a new class of 20 nm × 2 nm ternary alloy FePtM (M = Cu, Ni) nanorods (NRs) with controlled compositions. Supported on carbon support and treated with acetic acid as well as electrochemical etching, these FePtM NRs were converted into core/shell FePtM/Pt NRs. These core/shell NRs, especially FePtCu/Pt NRs, exhibited much improved ORR activity and durability. The Fe10Pt75Cu15 NRs showed a mass current densities of 1.034 A/mgPt at 512 mV vs Ag/AgCl and 0.222 A/mgPt at 557 mV vs Ag/AgCl, which are much higher than those for a commercial Pt catalyst (0.138 and 0.035 A/mgPt, respectively). Our controlled synthesis provides a general approach to core/shell NRs with enhanced catalysis for the ORR or other chemical reactions.
Co-reporter:Jonghun Lee, Sen Zhang, and Shouheng Sun
Chemistry of Materials 2013 Volume 25(Issue 8) pp:1293
Publication Date(Web):February 14, 2013
DOI:10.1021/cm3040517
This review highlights the recent progress in synthesizing some representative metal-oxide nanocrystals (MONCs) with controlled magnetic, electronic, and optical properties for potentially important technological applications. It first introduces the synthesis of MONCs of magnetite (Fe3O4), ferrite (MFe2O4), and hollow Fe3O4 with controlled magnetic properties. It then highlights the potentials of these nanocrystals (NCs) as highly effective contrast enhancement agents for magnetic resonance imaging (MRI) and as efficient nanoplatforms for target specific drug delivery. The review further surveys some typical high-temperature solution-phase approaches to the common semiconductive MONCs of indium tin oxide (ITO, In2O3·xSnO2)/tin oxide (SnO2), zinc oxide (ZnO), titanium oxide (TiO2), and copper oxide (Cu2O or CuO) with controlled band-gap energies and optical properties for optoelectronics, photocatalysis, and sensor applications.Keywords: chemical synthesis; metal oxide; nanocrystals; nanomedicine; optoelectronics; photocatalysis;
Co-reporter:Önder Metin, Xiaolian Sun and Shouheng Sun
Nanoscale 2013 vol. 5(Issue 3) pp:910-912
Publication Date(Web):10 Dec 2012
DOI:10.1039/C2NR33637E
Monodisperse 4 nm AuPd alloy nanoparticles with controlled composition were synthesized by co-reduction of hydrogen tetrachloroaurate(III) hydrate and palladium(II) acetylacetonate with a borane–morpholine complex in oleylamine. These NPs showed high activity (TOF = 230 h−1) and stability in catalyzing formic acid dehydrogenation and hydrogen production in water at 50 °C without any additives.
Co-reporter:Tao Jin, Shaojun Guo, Jing-lin Zuo and Shouheng Sun
Nanoscale 2013 vol. 5(Issue 1) pp:160-163
Publication Date(Web):06 Nov 2012
DOI:10.1039/C2NR33060A
Monodisperse 4.5 nm Pd nanoparticles (NPs) were synthesized by solution phase reduction of palladium acetylacetonate with morpholine borane in a mixture of oleylamine and 1-octadecene. These NPs were assembled on graphene uniformly in the form of a monolayer, and showed much enhanced catalysis for electrooxidation of formic acid. The work demonstrates the great potential of graphene as a support to enhance NP catalysis and stability for important chemical oxidation reactions.
Co-reporter:Dr. Shaojun Guo;Dongguo Li;Huiyuan Zhu;Sen Zhang;Dr. Nenad M. Markovic;Dr. Vojislav R. Stamenkovic; Shouheng Sun
Angewandte Chemie International Edition 2013 Volume 52( Issue 12) pp:3465-3468
Publication Date(Web):
DOI:10.1002/anie.201209871
Co-reporter:Sen Zhang;Dr. Önder Metin;Dr. Dong Su;Dr. Shouheng Sun
Angewandte Chemie International Edition 2013 Volume 52( Issue 13) pp:3681-3684
Publication Date(Web):
DOI:10.1002/anie.201300276
Co-reporter:Dr. Shaojun Guo;Sen Zhang; Shouheng Sun
Angewandte Chemie International Edition 2013 Volume 52( Issue 33) pp:8526-8544
Publication Date(Web):
DOI:10.1002/anie.201207186
Abstract
Advances in chemical syntheses have led to the formation of various kinds of nanoparticles (NPs) with more rational control of size, shape, composition, structure and catalysis. This review highlights recent efforts in the development of Pt and non-Pt based NPs into advanced nanocatalysts for efficient oxygen reduction reaction (ORR) under fuel-cell reaction conditions. It first outlines the shape controlled synthesis of Pt NPs and their shape-dependent ORR. Then it summarizes the studies of alloy and core–shell NPs with controlled electronic (alloying) and strain (geometric) effects for tuning ORR catalysis. It further provides a brief overview of ORR catalytic enhancement with Pt-based NPs supported on graphene and coated with an ionic liquid. The review finally introduces some non-Pt NPs as a new generation of catalysts for ORR. The reported new syntheses with NP parameter-tuning capability should pave the way for future development of highly efficient catalysts for applications in fuel cells, metal-air batteries, and even in other important chemical reactions.
Co-reporter:Dr. Shaojun Guo;Sen Zhang; Shouheng Sun
Angewandte Chemie 2013 Volume 125( Issue 33) pp:8686-8705
Publication Date(Web):
DOI:10.1002/ange.201207186
Abstract
Fortschritte in der chemischen Synthese führen zu einer immer besseren Kontrolle der Größe, Form, Zusammensetzung, Struktur und Katalyseeigenschaften von Nanopartikeln (NPs). Dieser Aufsatz gibt einen Überblick über Platin- und andere Nanopartikel für den Einsatz als Nanokatalysatoren in der Sauerstoffreduktionsreaktion (ORR) unter den Reaktionsbedingungen einer Brennstoffzelle. Zunächst werden die formkontrollierte Synthese von Pt-NPs und der Einfluss der Partikelform auf die katalytischen Eigenschaften in der ORR diskutiert. Anschließend werden NP-Legierungen und Kern-Schale-NPs mit optimierten elektronischen und geometrischen Effekten sowie Pt-NPs auf Graphenträgern oder mit einer Hülle aus einer ionischen Flüssigkeit betrachtet. Schließlich werden einige andere Metall-NPs diskutiert, die eine neue Generation von Katalysatoren für die ORR darstellen. Die vorgestellten Synthesewege ermöglichen eine zielgerichtete Steuerung der Eigenschaften der NPs und bilden eine gute Ausgangsbasis für die Entwicklung hochwirksamer Katalysatoren für Brennstoffzellen, Metall-Luft-Batterien und andere wichtige chemische Reaktionen.
Co-reporter:Önder Metin;Sally Fae Ho;Cemalettin Alp;Hasan Can;Max N. Mankin
Nano Research 2013 Volume 6( Issue 1) pp:10-18
Publication Date(Web):2013 January
DOI:10.1007/s12274-012-0276-4
Co-reporter:Xiaolian Sun, Natalie Frey Huls, Aruna Sigdel, and Shouheng Sun
Nano Letters 2012 Volume 12(Issue 1) pp:246-251
Publication Date(Web):December 1, 2011
DOI:10.1021/nl2034514
Monodisperse 35 nm FeO nanoparticles (NPs) were synthesized and oxidized in a dry air atmosphere into core/shell FeO/Fe3O4 NPs with both FeO core and Fe3O4 shell dimensions controlled by reaction temperature and time. Temperature-dependent magnetic properties were studied on FeO/Fe3O4 NPs obtained from the FeO NPs oxidized at 60 and 100 °C for 30 min. A large exchange bias (shift in the hysteresis loop) was observed in these core/shell NPs. The relative dimensions of the core and shell determine not only the coercivity and exchange field but also the dominant reversal mechanism of the ferrimagnetic Fe3O4 component. This is the first time demonstration of tuning exchange bias and of controlling asymmetric magnetization reversal in FeO/Fe3O4 NPs with antiferromagnetic core and ferrimagnetic shell.
Co-reporter:Vismadeb Mazumder, Miaofang Chi, Max N. Mankin, Yi Liu, Önder Metin, Daohua Sun, Karren L. More, and Shouheng Sun
Nano Letters 2012 Volume 12(Issue 2) pp:1102-1106
Publication Date(Web):January 25, 2012
DOI:10.1021/nl2045588
Monodisperse CoPd nanoparticles (NPs) were synthesized and studied for catalytic formic acid (HCOOH) oxidation (FAO). The NPs were prepared by coreduction of Co(acac)2 (acac = acetylacetonate) and PdBr2 at 260 °C in oleylamine and trioctylphosphine, and their sizes (5–12 nm) and compositions (Co10Pd90 to Co60Pd40) were controlled by heating ramp rate, metal salt concentration, or metal molar ratios. The 8 nm CoPd NPs were activated for HCOOH oxidation by a simple ethanol wash. In 0.1 M HClO4 and 2 M HCOOH solution, their catalytic activities followed the trend of Co50Pd50 > Co60Pd40 > Co10Pd90 > Pd. The Co50Pd50 NPs had an oxidation peak at 0.4 V with a peak current density of 774 A/gPd. As a comparison, commercial Pd catalysts showed an oxidation peak at 0.75 V with peak current density of only 254 A/gPd. The synthesis procedure could also be extended to prepare CuPd NPs when Co(acac)2 was replaced by Cu(ac)2 (ac = acetate) in an otherwise identical condition. The CuPd NPs were less active catalysts than CoPd or even Pd for FAO in HClO4 solution. The synthesis provides a general approach to Pd-based bimetallic NPs and will enable further investigation of Pd-based alloy NPs for electro-oxidation and other catalytic reactions.
Co-reporter:Xiaolian Sun, Shaojun Guo, Yi Liu, and Shouheng Sun
Nano Letters 2012 Volume 12(Issue 9) pp:4859-4863
Publication Date(Web):August 27, 2012
DOI:10.1021/nl302358e
Dumbbell-like PtxPd100–x–Fe3O4 nanoparticles (NPs) were synthesized and studied for electrocatalytic reduction and sensing of H2O2. In 0.1 M phosphate buffered saline (PBS) solution, the 4–10 nm PtxPd100–x–Fe3O4 NPs showed the Pt/Pd composition-dependent catalysis with Pt48Pd52–Fe3O4 NPs having the best activity. The Pt48Pd52–Fe3O4 NPs were tested for H2O2 detection, and their H2O2 detection limit reached 5 nM, which was suitable for monitoring H2O2 generated from Raw 264.7 cells. These dumbbell-like PtPd–Fe3O4 NPs are the most sensitive probe ever reported and can be used to achieve real-time quantitative detection of H2O2 in biological environment for biological and biomedical applications.
Co-reporter:Jonghun Lee ; Sunghwan Lee ; Guanglai Li ; Melissa A. Petruska ; David C. Paine
Journal of the American Chemical Society 2012 Volume 134(Issue 32) pp:13410-13414
Publication Date(Web):July 21, 2012
DOI:10.1021/ja3044807
Monodisperse 11 nm indium tin oxide (ITO) nanocrystals (NCs) were synthesized by thermal decomposition of indium acetylacetonate, In(acac)3, and tin bis(acetylacetonate)dichloride, Sn(acac)2Cl2, at 270 °C in 1-octadecene with oleylamine and oleic acid as surfactants. Dispersed in hexane, these ITO NCs were spin-cast on centimeter-wide glass substrates, forming uniform ITO NC assemblies with root-mean-square roughness of 2.9 nm. The assembly thickness was controlled by ITO NC concentrations in hexane and rotation speeds of the spin coater. Via controlled thermal annealing at 300 °C for 6 h under Ar and 5% H2, the ITO NC assemblies became conductive and transparent with the 146 nm-thick assembly showing 5.2 × 10–3 Ω·cm (Rs = 356 Ω/sq) resistivity and 93% transparency in the visible spectral range—the best values ever reported for ITO NC assemblies prepared from solution phase processes. The stable hexane dispersion of ITO NCs was also readily spin-cast on polyimide (Tg ∼360 °C), and the resultant ITO assembly exhibited a comparable conductivity and transparency to the assembly on a glass substrate. The reported synthesis and assembly provide a promising solution to the fabrication of transparent and conducting ITO NCs on flexible substrates for optoelectronic applications.
Co-reporter:Shaojun Guo
Journal of the American Chemical Society 2012 Volume 134(Issue 5) pp:2492-2495
Publication Date(Web):January 26, 2012
DOI:10.1021/ja2104334
Seven-nanometer FePt nanoparticles (NPs) were synthesized and assembled on graphene (G) by a solution-phase self-assembly method. These G/FePt NPs were a more active and durable catalyst for oxygen reduction reaction (ORR) in 0.1 M HClO4 than the same NPs or commercial Pt NPs deposited on conventional carbon support. The G/FePt NPs annealed at 100 °C for 1 h under Ar + 5% H2 exhibited specific ORR activities of 1.6 mA/cm2 at 0.512 V and 0.616 mA/cm2 at 0.557 V (vs Ag/AgCl). As a comparison, the commercial Pt NPs (2–3 nm) had specific activities of 0.271 and 0.07 mA/cm2 at the same potentials. The G/FePt NPs were also much more stable in the ORR condition and showed nearly no activity change after 10 000 potential sweeps. The work demonstrates that G is indeed a promising support to improve NP activity and durability for practical catalytic applications.
Co-reporter:Sen Zhang ; Shaojun Guo ; Huiyuan Zhu ; Dong Su
Journal of the American Chemical Society 2012 Volume 134(Issue 11) pp:5060-5063
Publication Date(Web):March 1, 2012
DOI:10.1021/ja300708j
Using FePtAu nanoparticles (NPs) as an example, this Communication demonstrates a new structure-control strategy to tune and optimize NP catalysis. The presence of Au in FePtAu facilitates FePt structure transformation from chemically disordered face-centered cubic (fcc) structure to chemically ordered face-centered tetragonal (fct) structure, and further promotes formic acid oxidation reaction (FAOR). The fct-FePtAu NPs have mass activity as high as 2809.9 mA/mg Pt and retain 92.5% of this activity after a 13 h stability test. They become the most efficient NP catalyst ever reported for FAOR. This structure-control strategy can be extended to other multimetallic NP systems, providing a general approach to advanced NP catalysts with desired activity and durability control for practical applications.
Co-reporter:Dongguo Li, Chao Wang, Dusan Tripkovic, Shouheng Sun, Nenad M. Markovic, and Vojislav R. Stamenkovic
ACS Catalysis 2012 Volume 2(Issue 7) pp:1358
Publication Date(Web):May 21, 2012
DOI:10.1021/cs300219j
Colloidal nanoparticles prepared by solution synthesis with robust control over particle size, shape, composition, and structure have shown great potential for catalytic applications. However, such colloidal nanoparticles are usually capped with organic ligands (as surfactants) and cannot be directly used as catalyst. We have studied the effect of surfactant removal on the electrocatalytic performance of Pt nanoparticles made by organic solution synthesis. Various methods were applied to remove the oleylamine surfactant, which included thermal annealing, acetic acid washing, and UV-Ozone irradiation, and the treated nanoparticles were applied as electrocatalysts for the oxygen reduction reaction. It was found that the electrocatalytic performance, including electrochemically active surface area and catalytic activity, was strongly dependent on the pretreatment. Among the methods studied here, low-temperature thermal annealing (∼185 °C) in air was found to be the most effective for surface cleaning without inducing particle size and morphology changes.Keywords: catalysis; nanoparticles; organic solution synthesis; oxygen reduction reaction; surfactant removal;
Co-reporter:Daohua Sun, Vismadeb Mazumder, Önder Metin, and Shouheng Sun
ACS Catalysis 2012 Volume 2(Issue 6) pp:1290
Publication Date(Web):May 15, 2012
DOI:10.1021/cs300211y
Monodisperse 7 nm CoPd nanoparticles (NPs) with controlled compositions were synthesized and studied for their catalyzing methanolysis of ammonia borane (AB). The NPs were prepared by the reduction of cobalt(II) acetylacetonate and palladium(II) bromide in the presence of oleylamine and trioctylphosphine. Deposited on a carbon support without any specific surface treatment, these NPs were active catalysts for methanolysis of AB, and their activities were composition-dependent. Among all CoPd catalysts tested, Co48Pd52 NPs exhibited the highest catalytic activity and stability. Kinetic study showed that the catalytic methanolysis of AB was first-order with respect to catalyst concentration and zero-order with respect to AB concentration. The activation energy for the methanolysis was calculated to be 25.5 kJ mol–1. These CoPd NPs are a promising catalyst for AB methanolysis and for developing a highly efficient hydrogen generation system for power applications.Keywords: ammonia borane; bimetallic nanoparticles; cobalt−palladium alloy; hydrogen generation; methanolysis;
Co-reporter:Pinxian Xi, Kai Cheng, Xiaolian Sun, Zhengzhi Zeng and Shouheng Sun
Chemical Communications 2012 vol. 48(Issue 24) pp:2952-2954
Publication Date(Web):23 Jan 2012
DOI:10.1039/C2CC18122C
Magnetic 8 nm Fe3O4 nanoparticles (NPs) were synthesized and modified with dopamine (DPA) and polyethylene glycol (PEG) diacid. The water soluble Fe3O4–DPA–PEG NPs were then conjugated with the fluorescent Eu(III) complex of tris(dibenzoylmethane)-5-amino-1,10-phenanthroline (BMAP), giving an Fe3O4–DPA–PEG–BMAP–Eu NP conjugate. The conjugate was both colloidally and chemically stable in phosphate buffered solutions and could be used as a probe for magnetic resonance and fluorescent imaging.
Co-reporter:Dr. Shaojun Guo;Sen Zhang;Liheng Wu ; Shouheng Sun
Angewandte Chemie International Edition 2012 Volume 51( Issue 47) pp:11770-11773
Publication Date(Web):
DOI:10.1002/anie.201206152
Co-reporter:Dr. Shaojun Guo;Sen Zhang;Liheng Wu ; Shouheng Sun
Angewandte Chemie 2012 Volume 124( Issue 47) pp:11940-11943
Publication Date(Web):
DOI:10.1002/ange.201206152
Co-reporter:Don Ho, Xiaolian Sun, and Shouheng Sun
Accounts of Chemical Research 2011 Volume 44(Issue 10) pp:875
Publication Date(Web):June 10, 2011
DOI:10.1021/ar200090c
Effective medical care requires the concurrent monitoring of medical treatment. The combination of imaging and therapeutics allows a large degree of control over the treatment efficacy and is now commonly referred to as “theranostics”. Magnetic nanoparticles (NPs) provide a unique nanoplatform for theranostic applications because of their biocompatibility, their responses to the external magnetic field, and their sizes which are comparable to that of functional biomolecules. Recent studies of magnetic NPs for both imaging and therapeutic applications have led to greater control over size, surface functionalization, magnetic properties, and specific binding capabilities of the NPs. The combination of the deep tissue penetration of the magnetic field and the ability of magnetic NPs to enhance magnetic resonance imaging sensitivity and magnetic heating efficiency makes magnetic NPs promising candidates for successful future theranostics.In this Account, we review recent advances in the synthesis of magnetic NPs for biomedical applications such as magnetic resonance imaging (MRI) and magnetic fluid hyperthermia (MFH). Our focus is on iron oxide (Fe3O4) NPs, gold-iron oxide (Au–Fe3O4) NPs, metallic iron (Fe) NPs, and Fe-based alloy NPs, such as iron-cobalt (FeCo) and iron-platinum (FePt) NPs. Because of the ease of fabrication and their approved clinical usage, Fe3O4 NPs with controlled sizes and surface chemistry have been studied extensively for MRI and MFH applications. Porous hollow Fe3O4 NPs are expected to have similar magnetic, chemical, and biological properties as the solid Fe3O4 NPs, and their structures offer the additional opportunity to store and release drugs at a target. The Au–Fe3O4 NPs combine both magnetically active Fe3O4 and optically active Au within one nanostructure and are a promising NP platform for multimodal imaging and therapeutics. Metallic Fe and FeCo NPs offer the opportunity for probes with even higher magnetizations. However, metallic NPs are normally very reactive and are subject to fast oxidation in biological solutions. Once they are coated with a layer of polycrystalline Fe3O4 or a graphitic shell, these metallic NPs are more stable and provide better contrast for MRI and more effective heating for MFH. FePt NPs are chemically more stable than Fe and FeCo NPs and have shown great potential as contrast agents for both MRI and X-ray computed tomography (CT) and as robust probes for controlled heating in MFH.
Co-reporter:Chao Wang, Dennis van der Vliet, Karren L. More, Nestor J. Zaluzec, Sheng Peng, Shouheng Sun, Hideo Daimon, Guofeng Wang, Jeffrey Greeley, John Pearson, Arvydas P. Paulikas, Goran Karapetrov, Dusan Strmcnik, Nenad M. Markovic, and Vojislav R. Stamenkovic
Nano Letters 2011 Volume 11(Issue 3) pp:919-926
Publication Date(Web):August 12, 2010
DOI:10.1021/nl102369k
We report the design and synthesis of multimetallic Au/Pt-bimetallic nanoparticles as a highly durable electrocatalyst for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. This system was first studied on well-defined Pt and FePt thin films deposited on a Au(111) surface, which has guided the development of novel synthetic routes toward shape-controlled Au nanoparticles coated with a Pt-bimetallic alloy. It has been demonstrated that these multimetallic Au/FePt3 nanoparticles possess both the high catalytic activity of Pt-bimetallic alloys and the superior durability of the tailored morphology and composition profile, with mass-activity enhancement of more than 1 order of magnitude over Pt catalysts. The reported synergy between well-defined surfaces and nanoparticle synthesis offers a persuasive approach toward advanced functional nanomaterials.
Co-reporter:Lise-Marie Lacroix, Natalie Frey Huls, Don Ho, Xiaolian Sun, Kai Cheng, and Shouheng Sun
Nano Letters 2011 Volume 11(Issue 4) pp:1641-1645
Publication Date(Web):March 18, 2011
DOI:10.1021/nl200110t
We report a facile synthesis of body centered cubic (bcc) Fe nanoparticles (NPs) via the thermal decomposition of iron pentacarbonyl, Fe(CO)5, in the presence of hexadecylammonium chloride. These bcc-Fe NPs exhibit a drastically increased stability and magnetic moment (Ms = 164 A·m2·kg−1Fe) even in physiological solutions, and have much enhanced magnetic imaging contrast (r2 = 220 s−1·mM−1) and heating (SAR = 140 W·g−1Fe) effects. They may serve as robust probes for imaging and therapeutic applications.
Co-reporter:Yi Liu, Chao Wang, Yujie Wei, Leyi Zhu, Dongguo Li, J. Samuel Jiang, Nenad M. Markovic, Vojislav R. Stamenkovic, and Shouheng Sun
Nano Letters 2011 Volume 11(Issue 4) pp:1614-1617
Publication Date(Web):February 28, 2011
DOI:10.1021/nl104548g
Modulation of Pd nanoparticle (NP) crystallinity is achieved by switching the surfactants of different binding strengths. Pd NPs synthesized in the presence of weak binding surfactants such as oleylamine possess polyhedral shapes and a polycrystalline nature. When oleylamine is substituted by trioctylphosphine, a much stronger binding surfactant, the particles become spherical and their crystallinity decreases significantly. Moreover, the Pd NPs reconvert their polycrystalline structure when the surfactant is switched back to oleylamine. Through control experiments and molecular dynamics simulation, we propose that this unusual nanocrystallinity transition induced by surfactant exchange was resulted from a counterbalance between the surfactant binding energy and the nanocrystal adhesive energy. The findings represent a novel postsynthetic approach to tailoring the structure and corresponding functional performance of nanomaterials.
Co-reporter:Shaojun Guo, Sen Zhang, Xiaolian Sun, and Shouheng Sun
Journal of the American Chemical Society 2011 Volume 133(Issue 39) pp:15354-15357
Publication Date(Web):September 6, 2011
DOI:10.1021/ja207308b
We report a facile synthesis of ultrathin (2.5 nm) trimetallic FePtPd alloy nanowires (NWs) with tunable compositions and controlled length (<100 nm). The NWs were made by thermal decomposition of Fe(CO)5 and sequential reduction of Pt(acac)2 (acac = acetylacetonate) and Pd(acac)2 at temperatures from 160 to 240 °C. These FePtPd NWs showed composition-dependent catalytic activity and stability for methanol oxidation reaction. Among FePtPd and FePt NWs as well as Pd, Pt, and PtPd nanoparticles (NPs) studied in 0.2 M methanol and 0.1 M HClO4 solution, the Fe28Pt38Pd34 NWs showed the highest activity, with their mass current density reaching 488.7 mA/mg Pt and peak potential for methanol oxidation decreasing to 0.614 V from 0.665 V (Pt NP catalyst). The NW catalysts were also more stable than the NP catalysts, with the Fe28Pt38Pd34 NWs retaining the highest mass current density (98.1 mA/mg Pt) after a 2 h current–time test at 0.4 V. These trimetallic NWs are a promising new class of catalyst for methanol oxidation reaction and for direct methanol fuel cell applications.
Co-reporter:Yi Liu, Dongguo Li, Vojislav R. Stamenkovic, Stuart Soled, Juan D. Henao, and Shouheng Sun
ACS Catalysis 2011 Volume 1(Issue 12) pp:1719
Publication Date(Web):November 4, 2011
DOI:10.1021/cs200430r
Monodisperse Pt3Sn alloy nanoparticles (NPs) were synthesized by a controlled coreduction of Pt(II) acetylacetonate and Sn(II) acetylacetonate at 180–280 °C in 1-octadecene. In the synthesis, oleylamine was used as a reducing agent, and oleylamine/oleic acid served as surfactants. The sizes of the Pt3Sn NPs were tuned from 4 to 7 nm by controlling the metal salt injection temperatures from 180 to 240 °C. These monodisperse Pt3Sn NPs were highly active for CO and methanol oxidation in 0.1 M HClO4 solutions, and their activity and stability could be further improved by a postsynthesis thermal treatment at 400 °C in Ar + 5% H2 for 1 h. They are promising as a practical catalyst for CO and methanol oxidation reactions in polymer electrolyte membrane fuel cell conditions.Keywords: catalysis; CO oxidation; methanol oxidation; Pt3Sn nanoparticles; synthesis;
Co-reporter:Max N. Mankin, Vismadeb Mazumder, and Shouheng Sun
Chemistry of Materials 2011 Volume 23(Issue 2) pp:132
Publication Date(Web):December 20, 2010
DOI:10.1021/cm101938e
We report a one-pot solution-phase synthesis of Pt nanocubes and nanopods by adjusting the reaction time between 1 and 15 min. The nanocubes were synthesized in 1 min by controlled burst nucleation of Pt in the presence of low boiling point solvents hexane and acetone, while nanopods were obtained in 15 min via the secondary growth of polyhedral particles on the vertices of the existing Pt nanocubes in the presence of N-methylpyrrolidone. The Pt nanostructures were characterized by transmission electron microscopy, powder X-ray diffraction, and cyclic voltammetry. The nanocubes are dominated by (100) facets while the nanopods have more (111) character. The burst nucleation and secondary growth mediated by hexane/acetone and N-methylpyrrolidone may lead to new, or more easily synthesized, morphologies of Pt and other transition metal nanostructures.
Co-reporter:Yi Liu, Miaofang Chi, Vismadeb Mazumder, Karren L. More, Stuart Soled, Juan D. Henao, and Shouheng Sun
Chemistry of Materials 2011 Volume 23(Issue 18) pp:4199
Publication Date(Web):August 19, 2011
DOI:10.1021/cm2014785
PdPt alloy nanoparticles (NPs) are promising catalysts for various chemical reactions because of the presence of powerful catalytic components of Pt and Pd on the surface of one nanostructure. In this paper, we report a facile synthesis of polyhedral PdPt alloy NPs via coreduction of Pd(acac)2 (acac = acetylacetonate) and Pt(acac)2 with morpholine borane in oleylamine at 90 and 180 °C. In the synthesis, the molar ratio of the two metal precursors added in the reaction mixture was carried over to the final PdPt NP product, and compositions of the PdPt NPs were readily tuned from Pd88Pt12 to Pd34Pt66. These PdPt NPs show the composition-dependent catalytic activity for methanol oxidation, with NPs in 40–60 atomic % Pt exhibiting the superior activity and durability.Keywords: bimetallic nanoparticles; methanol oxidation; palladium platinum alloy;
Co-reporter:Hongwang Zhang, Sheng Peng, Chuan-bing Rong, J. Ping Liu, Ying Zhang, M. J. Kramer and Shouheng Sun
Journal of Materials Chemistry A 2011 vol. 21(Issue 42) pp:16873-16876
Publication Date(Web):22 Jun 2011
DOI:10.1039/C1JM11753J
We report a facile synthesis of ferromagnetic SmCo nanoparticles (NPs) via a controlled reduction of SmCo–O NPs. The SmCo–O NPs were prepared by co-precipitation of Co(II) and Sm(III) acetates with hexadecyl-trimethylammonium hydroxide and were embedded in a CaO matrix. The 7 nm SmCo3.6–O NPs were reduced by Ca at 960 °C and converted into ferromagnetic 6 nm SmCo5 NPs with their coercivities reaching 7.2 kOe. The synthesis provides a viable route to ferromagnetic SmCo NPs with controlled compositions and magnetism for high performance permanent magnetic applications.
Co-reporter:Yi Liu, Dongguo Li and Shouheng Sun
Journal of Materials Chemistry A 2011 vol. 21(Issue 34) pp:12579-12587
Publication Date(Web):28 Jun 2011
DOI:10.1039/C1JM11605C
This feature article highlights the recent advances in the synthesis of Pt-based binary alloy and core–shell nanoparticles (NPs) for magnetic, catalytic and biomedical applications. These composite NPs are made by thermal decomposition and reduction of metal precursors in a high boiling point organic solvent with their size, shape, composition and shell thickness controlled by metal precursor concentrations, surfactant concentrations and reaction temperatures. The as-synthesized alloy NPs adopt typically the face centered cubic (fcc) structure and can be further converted into the face centered tetragonal (fct) structure upon high temperature annealing. The NP size, shape, composition and structure dependent magnetism and catalysis are further illustrated. The studies show that the fct structured NPs are ferromagnetic and are promising components for magnetic data storage media, and that the core–shell NPs are better catalysts for fuel cell reactions with much enhanced activity and durability, and that the fcc structured FePt NPs have great potential for multimodality imaging and for therapeutic applications.
Co-reporter:Pinxian Xi, Kai Cheng, Xiaolian Sun, Zhengzhi Zeng and Shouheng Sun
Journal of Materials Chemistry A 2011 vol. 21(Issue 31) pp:11464-11467
Publication Date(Web):03 Dec 2010
DOI:10.1039/C0JM03119D
A fluorescent ruthenium (Ru) complex is coupled to magnetic Fe3O4 nanoparticles (NPs) via3-(3,4-dihydroxyphenyl) propanoic acid (DHPPA) and O,O′-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (PPG-PEG-PPG-diamine). The resultant Ru–Fe3O4 NP conjugate shows excellent colloidal, photochemical and magnetic stability, and is promising as a dual functional probe for biological imaging applications.
Co-reporter:Rui Hao, Jing Yu, Yanglong Hou and Shouheng Sun
Chemical Communications 2011 vol. 47(Issue 32) pp:9095-9097
Publication Date(Web):04 Jul 2011
DOI:10.1039/C1CC12759D
A general one-pot protocol is reported to prepare hollow or porous manganese (Mn) oxide, phosphate, sulfide nanoparticles (NPs) via a controlled ion transfer process.
Co-reporter:Haruo Imagawa ; Akihiko Suda ; Kae Yamamura
The Journal of Physical Chemistry C 2011 Volume 115(Issue 5) pp:1740-1745
Publication Date(Web):January 18, 2011
DOI:10.1021/jp109878j
Monodisperse polyhedral nanoparticles (NPs) and nanorods (NRs) of cerium dioxide, CeO2, were synthesized by thermal decomposition of ammonium cerium(IV) nitrate, (NH4)2Ce(NO3)6, at 180 °C in an organic solution of oleylamine (OAm) and/or oleic acid (OA). The 4 nm CeO2 NPs were synthesized in diphenyl ether solution of OAm and OA with the molar ratio of Ce/OAm/OA = 1:3:3, while the 6 nm CeO2 NPs were made in 1-octadecene solution of OAm with Ce/OAm = 1:6. The NRs were formed in 1-octadecene with Ce/OAm/OA = 1:3:1.5. The CeO2 NPs were assembled on γ-Al2O3 via polyvinylpyrrolidone and were annealed at 500 °C under air to remove organic coating. They were well-dispersed on Al2O3 and showed the increased oxygen storage capacity compared to the physical mixture of aggregated CeO2 and γ-Al2O3 powder. The reported CeO2 NPs are promising for oxygen storage and release applications.
Co-reporter:Daohua Sun, Vismadeb Mazumder, Önder Metin, and Shouheng Sun
ACS Nano 2011 Volume 5(Issue 8) pp:6458
Publication Date(Web):July 18, 2011
DOI:10.1021/nn2016666
Monodisperse 8 nm CoPd nanoparticles (NPs) with controlled compositions were synthesized by the reduction of cobalt acetylacetonate and palladium bromide in the presence of oleylamine and trioctylphosphine. These NPs were active catalysts for hydrogen generation from the hydrolysis of ammonia borane (AB), and their activities were composition dependent. Among the 8 nm CoPd catalysts tested for the hydrolysis of AB, the Co35Pd65 NPs exhibited the highest catalytic activity and durability. Their hydrolysis completion time and activation energy were 5.5 min and 27.5 kJ mol–1, respectively, which were comparable to the best Pt-based catalyst reported. The catalytic performance of the CoPd/C could be further enhanced by a preannealing treatment at 300 °C under air for 15 h with the hydrolysis completion time reduced to 3.5 min. This high catalytic performance of Co35Pd65 NP catalyst makes it an exciting alternative in pursuit of practical implementation of AB as a hydrogen storage material for fuel cell applications.Keywords: ammonia borane hydrolysis; bimetallic nanoparticles; cobalt−palladium alloy catalyst; heterogeneous catalysis; hydrogen storage
Co-reporter:Chao Wang, Yujie Wei, Hongyuan Jiang and Shouheng Sun
Nano Letters 2010 Volume 10(Issue 6) pp:2121-2125
Publication Date(Web):May 25, 2010
DOI:10.1021/nl100661v
The effect of mechanical disturbance on one-dimensional nanocrystal growth in solution phase is investigated by controlled growth of Au nanowires with and without stirring. While a static growth leads to straight, single-crystal Au nanowires, the mechanic disturbance by stirring tends to bend the nanowire growth, yielding nanowire kinks abundant in various types of crystal defects including dislocations, twin boundaries, and grain boundaries. Mechanical modeling and analysis is introduced to elucidate the nanowire growth mechanisms in these two conditions. The provided fundamental understanding of crystal defect formation at nanoscale could be applied to guide the development of advanced nanomaterials with shape control and unique mechanical properties.
Co-reporter:Vismadeb Mazumder ; Miaofang Chi ; Karren L. More
Journal of the American Chemical Society 2010 Volume 132(Issue 23) pp:7848-7849
Publication Date(Web):May 24, 2010
DOI:10.1021/ja1024436
We report a unique synthesis of core/shell Pd/FePt nanoparticles (NPs) and their catalysis of the oxygen reduction reaction (ORR). The uniform FePt shell is formed by controlled nucleation of Fe(CO)5 in the presence of a Pt salt and Pd NPs at designated reaction temperatures. The Pd/FePt NPs show FePt shell-dependent catalytic properties, and those having a 1 nm FePt shell exhibit a drastic increase in durability and activity (15 times more active with a 140 mV gain in onset potential in comparison with those having a 3 nm coating). These Pd/FePt NPs are promising new catalysts for practical fuel cell applications.
Co-reporter:Önder Metin ; Vismadeb Mazumder ; Saim Özkar
Journal of the American Chemical Society 2010 Volume 132(Issue 5) pp:1468-1469
Publication Date(Web):January 15, 2010
DOI:10.1021/ja909243z
Monodisperse nickel nanoparticles are prepared from the reduction of Ni(acac)2 with borane tributylamine in the presence of oleylamine and oleic acid. Without any special treatment to remove the surfactants, the as-synthesized Ni nanoparticles supported on the Ketjen carbon support exhibit high catalytic activity in hydrogen generation from the hydrolysis of the ammonia−borane (H3NBH3) complex with a total turnover frequency value of 8.8 mol of H2·(mol of Ni)−1·min−1. Such catalysis based on Ni nanoparticles represents a promising step toward the practical development of the H3NBH3 complex as a feasible hydrogen storage medium for fuel cell applications.
Co-reporter:Chao Wang ; Wende Tian ; Yong Ding ; Yu-qiang Ma ; Zhong Lin Wang ; Nenad M. Markovic ; Vojislav R. Stamenkovic ; Hideo Daimon
Journal of the American Chemical Society 2010 Volume 132(Issue 18) pp:6524-6529
Publication Date(Web):April 16, 2010
DOI:10.1021/ja101305x
Rational synthesis of Pt−Aun nanoparticles (NPs) has been achieved by overgrowing Au on Pt with n, the number of Pt−Au heterojunctions in each particle, controlled from 1 to 4, and the corresponding NPs in pear-, peanut-, or clover-like morphology. Monte Carlo simulation reveals that the morphology control can be correlated to a thermodynamic equilibrium of the Au coherence energy, the overall particle surface energy, and the heterogeneous Pt−Au interfacial energy in the composite system, which is manipulated by the seeding particle size and solvent polarity. The developed synthetic strategy together with the provided fundamental understanding of heterogeneous nucleation and heterostructure growth could have great potential toward the rational synthesis of composite nanomaterials with morphology control for advanced catalytic and other functional applications.
Co-reporter:Jaemin Kim ; Youngmin Lee
Journal of the American Chemical Society 2010 Volume 132(Issue 14) pp:4996-4997
Publication Date(Web):March 18, 2010
DOI:10.1021/ja1009629
We report the structure-controlled synthesis of FePt/MgO NPs and their catalysis for oxygen reduction reaction (ORR) in 0.5 M H2SO4 solution. The synthesis yields fcc-FePt/MgO and fct-FePt/MgO NPs with the MgO coating being readily removed for catalytic studies. The fct-FePt NPs show higher activity and durability than the fcc-FePt in the ORR condition. The results indicate that the fully ordered fct-FePt could serve as a practical Pt-based catalyst for fuel cell applications.
Co-reporter:Vismadeb Mazumder;Youngmin Lee
Advanced Functional Materials 2010 Volume 20( Issue 8) pp:1224-1231
Publication Date(Web):
DOI:10.1002/adfm.200902293
Abstract
This review focuses on the recent advances in the synthesis of nanoparticle (NP) catalysts of Pt-, Pd- and Au-based NPs as well as composite NPs. First, new developments in the synthesis of single-component Pt, Pd and Au NPs are summarized. Then the chemistry used to make alloy and composite NP catalysts aiming to enhance their activity and durability for fuel cell reactions is outlined. The review next introduces the exciting new research push in developing CoN/C and FeN/C as non-Pt catalysts. Examples of size-, shape- and composition-dependent catalyses for oxygen reduction at cathode and formic acid oxidation at anode are highlighted to illustrate the potentials of the newly developed NP catalysts for fuel cell applications.
Co-reporter:Youngmin Lee, Aviva Loew and Shouheng Sun
Chemistry of Materials 2010 Volume 22(Issue 3) pp:755
Publication Date(Web):June 24, 2009
DOI:10.1021/cm9013046
Polycrystalline Au nanoparticles (NPs) of 3, 6, and 8 nm were synthesized via solution phase reaction of HAuCl4·3H2O with tert-butylamine borane and oleylamine in tetrahydronaphthalene. The sizes of the Au NPs were tuned by varying the reaction temperatures (40−3 °C). For polycrystalline Au NPs made at room temperature or above, smaller NPs showed more positive onset potential in catalyzing oxygen reduction reaction (ORR) in 0.5 M KOH media. However the most active Au NPs were the 8 nm ones that were synthesized at 3 °C. We rationalized the ORR activity of these Au NPs by the ease of oleylamine surfactant removal and the degree of disorder in the polycrystalline structure. This was further confirmed by the low activity observed from the same Au NPs passivated with hexadecanethiol, or from the Au NPs with higher degree of crystallinity made from the etching of the composite Au−Fe3O4 NPs.
Co-reporter:Chao Wang, Hongfeng Yin, Sheng Dai and Shouheng Sun
Chemistry of Materials 2010 Volume 22(Issue 10) pp:3277
Publication Date(Web):April 26, 2010
DOI:10.1021/cm100603r
Heterogeneous dumbbell-like nanoparticles represent an important type of composite nanomaterial that has attracted growing interest. Here we report a general approach to noble metal−metal oxide dumbbell nanoparticles based on seed-mediated growth. Metal oxides are grown over the presynthesized noble metal seeds by thermal decomposition of metal carbonyl followed by oxidation in air. The as-synthesized dumbbell nanoparticles have intrinsic epitaxial linkage between the metal and the oxide, providing enhanced heterojunction interactions. Moreover, the properties of one component are readily modified by the other in these nanoparticles, as demonstrated by the enhanced catalytic activity toward CO oxidation of such dumbbell nanoparticles in comparison with their counterparts prepared by conversional methods. The heterojunction effects provided in such nanostructures thus offer another degree of freedom for tailoring material properties. The developed synthetic strategy could also be generalized to other systems and thus represent a general approach to heterogeneous nanomaterials for various functional applications.
Co-reporter:Kai Cheng, Shouheng Sun
Nano Today 2010 Volume 5(Issue 3) pp:183-196
Publication Date(Web):June 2010
DOI:10.1016/j.nantod.2010.04.002
This paper reviews recent advances in the synthesis of porous hollow nanoparticles (PHNPs) of iron oxide and Au for biomedical applications. It first summarizes the synthesis and characterization of various PHNPs of iron oxide and Au. It then outlines the common chemistry applied to make these PHNPs biocompatible and target-specific. Finally the review presents several representative examples to highlight the applications of these PHNPs for drug delivery and for hyperthermia cancer therapy.
Co-reporter:Önder Metin;Saim Özkar
Nano Research 2010 Volume 3( Issue 9) pp:676-684
Publication Date(Web):2010 September
DOI:10.1007/s12274-010-0031-7
Monodisperse Ni nanoparticles (NPs) have been synthesized by the reduction of nickel(II) acetylacetonate with the borane-tributylamine complex in a mixture of oleylamine and oleic acid. These Ni NPs are an active catalyst for the hydrolysis of the ammonia-borane (AB, H3N·BH3) complex under ambient conditions and their activities are dependent on the chemical nature of the oxide support that they were deposited on. Among various oxides (SiO2, Al2O3, and CeO2) tested, SiO2 was found to enhance Ni NP catalytic activity due to the etching of the 3.2 nm Ni NPs giving Ni(II) ions and the subsequent reduction of Ni(II) that led to the formation of 1.6 nm Ni NPs on the SiO2 surface. The kinetics of the hydrolysis of AB catalyzed by Ni/SiO2 was shown to be dependent on catalyst and substrate concentration as well as temperature. The Ni/SiO2 catalyst has a turnover frequency (TOF) of 13.2 mol H2·(mol Ni)−1 · min−1—the best ever reported for the hydrolysis of AB using a nickel catalyst, an activation energy of 34 kJ/mol ± 2 kJ/mol and a total turnover number of 15,400 in the hydrolysis of AB. It is a promising candidate to replace noble metals for catalyzing AB hydrolysis and for hydrogen generation under ambient conditions.
Co-reporter:Youngmin Lee;MiguelAngel Garcia Dr.;NatalieA. FreyHuls Dr.
Angewandte Chemie International Edition 2010 Volume 49( Issue 7) pp:1271-1274
Publication Date(Web):
DOI:10.1002/anie.200906130
Co-reporter:Baodui Wang;Jun Hai;Zengchen Liu;Qin Wang;Zhengyin Yang
Angewandte Chemie International Edition 2010 Volume 49( Issue 27) pp:4576-4579
Publication Date(Web):
DOI:10.1002/anie.201001373
Co-reporter:Vismadeb Mazumder;Dr. Miaofang Chi;Dr. Karren L. More; Shouheng Sun
Angewandte Chemie International Edition 2010 Volume 49( Issue 49) pp:9368-9372
Publication Date(Web):
DOI:10.1002/anie.201003903
Co-reporter:Youngmin Lee;MiguelAngel Garcia Dr.;NatalieA. FreyHuls Dr.
Angewandte Chemie 2010 Volume 122( Issue 7) pp:1293-1296
Publication Date(Web):
DOI:10.1002/ange.200906130
Co-reporter:Vismadeb Mazumder;Dr. Miaofang Chi;Dr. Karren L. More; Shouheng Sun
Angewandte Chemie 2010 Volume 122( Issue 49) pp:9558-9562
Publication Date(Web):
DOI:10.1002/ange.201003903
Co-reporter:Natalie A. Frey, Sheng Peng, Kai Cheng and Shouheng Sun
Chemical Society Reviews 2009 vol. 38(Issue 9) pp:2532-2542
Publication Date(Web):23 Jun 2009
DOI:10.1039/B815548H
This tutorial review summarizes the recent advances in the chemical synthesis and potential applications of monodisperse magnetic nanoparticles. After a brief introduction to nanomagnetism, the review focuses on recent developments in solution phase syntheses of monodisperse MFe2O4, Co, Fe, CoFe, FePt and SmCo5 nanoparticles. The review further outlines the surface, structural, and magnetic properties of these nanoparticles for biomedicine and magnetic energy storage applications.
Co-reporter:Jaemin Kim;Chuanbing Rong;J. Ping Liu
Advanced Materials 2009 Volume 21( Issue 8) pp:906-909
Publication Date(Web):
DOI:10.1002/adma.200801620
Co-reporter:Chao Wang, Hideo Daimon and Shouheng Sun
Nano Letters 2009 Volume 9(Issue 4) pp:1493-1496
Publication Date(Web):March 4, 2009
DOI:10.1021/nl8034724
Monodisperse dumbbell-like Pt−Fe3O4 nanoparticles are synthesized by epitaxial growth of Fe onto Pt nanoparticles followed by Fe oxidation. The nanoparticle size in the structure is tunable from 2 to 8 nm for Pt and 6 to 20 nm for Fe3O4. Pt nanoparticles in the Pt−Fe3O4 structure show a 20-fold increase in mass activity toward oxygen reduction reaction compared with the single component Pt nanoparticles and the commercial 3 nm Pt particles. The work proves that it is possible to maximize catalytic activity of the Pt nanoparticle catalyst through the control not only of Pt size and shape but also of its interaction with Fe3O4 nanoparticles.
Co-reporter:Chao Wang, Yujie Wei, Hongyuan Jiang and Shouheng Sun
Nano Letters 2009 Volume 9(Issue 12) pp:4544-4547
Publication Date(Web):2017-2-22
DOI:10.1021/nl903077t
Mechanical property of dumbbell-like Au−Fe3O4 nanoparticles (NPs) is investigated from a synthetic point of view by overgrowing Au2 on the Au1−Fe3O4 NPs. The competitive growth of Au2 on the preformed Au1−Fe3O4 NPs induced an interesting “tug-of-war” between Au2 and Fe3O4 in the formed Au2−Au1−Fe3O4 ternary nanostructure. An interpretation of the observed phenomena is proposed based on a mechanical analysis of the stress and strain distribution across the nanoparticle, which is further verified by control experiments with particle size tuned.
Co-reporter:Kai Cheng ; Sheng Peng ; Chenjie Xu
Journal of the American Chemical Society 2009 Volume 131(Issue 30) pp:10637-10644
Publication Date(Web):July 2, 2009
DOI:10.1021/ja903300f
We report a new approach to cisplatin storage and release using porous hollow nanoparticles (PHNPs) of Fe3O4. We prepared the PHNPs by controlled oxidation of Fe NPs at 250 °C followed by acid etching. The opening pores (∼2−4 nm) facilitated the cisplatin diffusion into the cavity of the hollow structure. The porous shell was stable in neutral or basic physiological conditions, and cisplatin escape from the cavity through the same pores was a diffusion-controlled slow process with t1/2 = 16 h. However, in low pH (<6) conditions, the pores were subject to acidic etching, resulting in wider pore gaps and faster release of cisplatin with t1/2 < 4 h. Once coupled with Herceptin to the surface, the cisplatin-loaded hollow NPs could target to breast cancer SK-BR-3 cells with IC50 reaching 2.9 μM, much lower than 6.8 μM needed for free cisplatin. Our model experiments indicate that the low pH-responsive PHNPs of Fe3O4 can be exploited as a cisplatin delivery vehicle for target-specific therapeutic applications.
Co-reporter:Yi Liu;Sheng Peng;Yong Ding;Chuanbing Rong;Jaemin Kim;J. Ping Liu;Zhong Lin Wang
Advanced Functional Materials 2009 Volume 19( Issue 19) pp:3146-3150
Publication Date(Web):
DOI:10.1002/adfm.200900900
Abstract
Fe3BO5 nanorods with diameters from 4 nm to 16 nm and length from 43 nm to 60 nm are synthesized by a facile thermal decomposition of iron acetylacetonate and t-butylamine borane (TBAB). TBAB is used to control the 1D growth and the aspect ratio of the nanorods. These Fe3BO5 nanorods are antiferromagnetic with TN = 174 K, which is higher than that of bulk Fe3BO5 (114 K).
Co-reporter:Zhichuan Xu, Chengmin Shen, Yanglong Hou, Hongjun Gao and Shouheng Sun
Chemistry of Materials 2009 Volume 21(Issue 9) pp:1778
Publication Date(Web):April 14, 2009
DOI:10.1021/cm802978z
Co-reporter:Chao Wang, Hongfeng Yin, Ryan Chan, Sheng Peng, Sheng Dai and Shouheng Sun
Chemistry of Materials 2009 Volume 21(Issue 3) pp:433
Publication Date(Web):January 21, 2009
DOI:10.1021/cm802753j
Co-reporter:Kaylie L. Young, Chenjie Xu, Jin Xie and Shouheng Sun
Journal of Materials Chemistry A 2009 vol. 19(Issue 35) pp:6400-6406
Publication Date(Web):01 Jul 2009
DOI:10.1039/B902373A
Monodisperse Fe3O4nanoparticles (NPs) originally synthesized with a hydrophobic oleylamine capping ligand were made water soluble and conjugated to the anticancer drug Methotrexate (MTX) using a new chemistry based on the readily available linker trichloro-s-triazine (TsT). This new linker is much more versatile than those that currently exist for attaching biomolecules to magnetic NPs. The MTX-conjugated NPs were found to be stable under physiological conditions for over 72 hours and MTX was shown to maintain its anticancer activity after conjugation to the NP surface. Through cell viability studies and intracellular uptake studies, MTX-conjugated NPs were shown to have targeting specificity for a tumor cell line (9L rat glioma) over a healthy cell line (Cultured Pulmonary Artery Endothelial). Additionally the MTX-conjugated NPs were visualized inside 9L cells using fluorescence microscopy to help elucidate their path within a cell after internalization.
Co-reporter:Chenjie Xu and Shouheng Sun
Dalton Transactions 2009 (Issue 29) pp:5583-5591
Publication Date(Web):01 May 2009
DOI:10.1039/B900272N
Superparamagnetic nanoparticles (NPs) have been attractive for medical diagnostics and therapeutics due to their unique magnetic properties and their ability to interact with various biomolecules of interest. The solution phase based chemical synthesis provides a near precise control on NP size, and monodisperse magnetic NPs with standard deviation in diameter of less than 10% are now routinely available. Upon controlled surface functionalization and coupling with fragments of DNA strands, proteins, peptides or antibodies, these NPs can be well-dispersed in biological solutions and used for drug delivery, magnetic separation, magnetic resonance imaging contrast enhancement and magnetic fluid hyperthermia. This Perspective reviews the common syntheses and controlled surface functionalization of monodisperse Fe3O4-based superparamagnetic NPs. It further outlines the exciting application potentials of these NPs in magnetic resonance imaging and drug delivery.
Co-reporter:Chao Wang;Sheng Peng;Lise-Marie Lacroix
Nano Research 2009 Volume 2( Issue 5) pp:380-385
Publication Date(Web):2009/05/01
DOI:10.1007/s12274-009-9037-4
We report the synthesis of high magnetic moment CoFe nanoparticles via the diffusion of Co and Fe in core/shell structured Co/Fe nanoparticles. In an organic solution, Co nanoparticles were coated with a layer of Fe to form a Co/Fe core/shell structure. Further raising the solution temperature led to inter-diffusion of Co and Fe and formation of CoFe alloy nanoparticles. These nanoparticles have high saturation magnetization of up to 192 emu/g CoFe and can be further stabilized by thermal annealing at 600 °C.
Co-reporter:Zhichuan Xu, Chengmin Shen, Shouheng Sun and H.-J. Gao
The Journal of Physical Chemistry C 2009 Volume 113(Issue 34) pp:15196-15200
Publication Date(Web):August 5, 2009
DOI:10.1021/jp905396r
Au nanowires were produced at the interface of air/water by immersing a Au coated platinum tip into the growth solution containing CTAB, HAuCl4, and ascorbic acid. The Au coating layer is composed of 10−30 nm Au islands and these Au islands initiated the growth of Au crystals, which further produced Au nanowires via the template effect of the aligned cationic surfactant CTAB monolayer at the interface.
Co-reporter:Chao Wang Dr.
Chemistry – An Asian Journal 2009 Volume 4( Issue 7) pp:1028-1034
Publication Date(Web):
DOI:10.1002/asia.200900002
Co-reporter:Jaemin Kim, Chuanbing Rong, Youngmin Lee, J. Ping Liu and Shouheng Sun
Chemistry of Materials 2008 Volume 20(Issue 23) pp:7242-7245
Publication Date(Web):November 6, 2008
DOI:10.1021/cm8024878
This paper reports an improved synthesis of hard magnetic fct-FePt nanoparticles (NPs) from reductive annealing of fcc-FePt/Fe3O4/MgO NPs followed by MgO removal. The fcc-FePt/Fe3O4 NPs are made by a one-pot reaction of Pt(acac)2 with Fe(CO)5 in the presence of oleic acid and oleylamine and are coated with a layer of MgO via the thermal decomposition of Mg(acac)2. The MgO coating prevents FePt from sintering under high temperature reductive annealing conditions. The fct-FePt NPs obtained from the 650 °C annealing of the fcc-FePt/Fe3O4/MgO NPs show a coercivity value of 2 T at 300 K, suitable for various nanomagnetic applications.
Co-reporter:Chenjie Xu, Glenn A. Tung and Shouheng Sun
Chemistry of Materials 2008 Volume 20(Issue 13) pp:4167
Publication Date(Web):June 4, 2008
DOI:10.1021/cm8008418
Co-reporter:Hongfeng Yin, Chao Wang, Haoguo Zhu, Steven H. Overbury, Shouheng Sun and Sheng Dai
Chemical Communications 2008 (Issue 36) pp:4357-4359
Publication Date(Web):25 Jul 2008
DOI:10.1039/B807591C
Highly active Au catalysts with a dumbbell-like heterostructure for CO oxidation were prepared through colloidal deposition method; both activities and stabilities were investigated under different experimental conditions.
Co-reporter:Sheng Peng, Jin Xie, Shouheng Sun
Journal of Solid State Chemistry 2008 Volume 181(Issue 7) pp:1560-1564
Publication Date(Web):July 2008
DOI:10.1016/j.jssc.2008.03.024
Monodispersed cobalt nanoparticles (NPs) with controllable size (8–14 nm) have been synthesized using thermal decomposition of dicobaltoctacarbonyl in organic solvent. The as-synthesized high magnetic moment (125 emu/g) Co NPs are dispersible in various organic solvents, and can be easily transferred into aqueous phase by surface modification using phospholipids. However, the modified hydrophilic Co NPs are not stable as they are quickly oxidized, agglomerated in buffer. Co NPs are stabilized by coating the MFe2O4 (M=Fe, Mn) ferrite shell. Core/shell structured bimagnetic Co/MFe2O4 nanocomposites are prepared with tunable shell thickness (1–5 nm). The Co/MFe2O4 nanocomposites retain the high magnetic moment density from the Co core, while gaining chemical and magnetic stability from the ferrite shell. Compared to Co NPs, the nanocomposites show much enhanced stability in buffer solution at elevated temperatures, making them promising for biomedical applications.The 10 nm/3 nm Co/MFe2O4 (M=Fe, Mn) bimagnetic core/shell nanocomposites are synthesized from the surface coating of ferrite shell over 10 nm Co nanoparticle seeds. The nanocomposites show much enhanced chemical and magnetic stability in solid state, organic solution and aqueous phase, and are promising for biomedical applications.
Co-reporter:Sheng Peng;Youngmin Lee;Chao Wang;Hongfeng Yin;Sheng Dai
Nano Research 2008 Volume 1( Issue 3) pp:229-234
Publication Date(Web):2008 September
DOI:10.1007/s12274-008-8026-3
Monodisperse Au nanoparticles (NPs) have been synthesized at room temperature via a burst nucleation of Au upon injection of the reducing agent t-butylamine-borane complex into a 1, 2, 3, 4-tetrahydronaphthalene solution of HAuCl4·3H2O in the presence of oleylamine. The as-synthesized Au NPs show size-dependent surface plasmonic properties between 520 and 530 nm. They adopt an icosahedral shape and are polycrystalline with multiple-twinned structures. When deposited on a graphitized porous carbon support, the NPs are highly active for CO oxidation, showing 100% CO conversion at −45 °C.
Co-reporter:Chenjie Xu;Jin Xie;Nathan Kohler;EdwardG. Walsh;Y. Eugene Chin
Chemistry – An Asian Journal 2008 Volume 3( Issue 3) pp:548-552
Publication Date(Web):
DOI:10.1002/asia.200700301
Abstract
Functionalization of monodisperse superparamagnetic magnetite (Fe3O4) nanoparticles for cell specific targeting is crucial for cancer diagnostics and therapeutics. Targeted magnetic nanoparticles can be used to enhance the tissue contrast in magnetic resonance imaging (MRI), to improve the efficiency in anticancer drug delivery, and to eliminate tumor cells by magnetic fluid hyperthermia. Herein we report the nucleus-targeting Fe3O4 nanoparticles functionalized with protein and nuclear localization signal (NLS) peptide. These NLS-coated nanoparticles were introduced into the HeLa cell cytoplasm and nucleus, where the particles were monodispersed and non-aggregated. The success of labeling was examined and identified by fluorescence microscopy and MRI. The work demonstrates that monodisperse magnetic nanoparticles can be readily functionalized and stabilized for potential diagnostic and therapeutic applications.
Co-reporter:Chao Wang;Hideo Daimon;Taigo Onodera;Tetsunori Koda
Angewandte Chemie International Edition 2008 Volume 47( Issue 19) pp:3588-3591
Publication Date(Web):
DOI:10.1002/anie.200800073
Co-reporter:Chao Wang;Hideo Daimon;Taigo Onodera;Tetsunori Koda
Angewandte Chemie 2008 Volume 120( Issue 19) pp:3644-3647
Publication Date(Web):
DOI:10.1002/ange.200800073
Co-reporter:Y. Hou;Z. Xu;C. Rong;S. Peng;S. Sun;J. P. Liu
Advanced Materials 2007 Volume 19(Issue 20) pp:3349-3352
Publication Date(Web):25 SEP 2007
DOI:10.1002/adma.200700891
SmCo5magnets are synthesized by the facile Ca reduction of core/shell-structured Co/Sm2O3nanoparticles, as schematically illustrated in the figure. The magnets exhibit coercivities reaching 24 kOe at 100 K and 8 kOe at room temperature. The synthesis represents an important first step towards the fabrication of SmCo-based exchange-spring nanocomposites for high-performance permanent magnet applications.
Co-reporter:J. Xie;C. Xu;Y. Hou;N. Kohler;S. Sun
Advanced Materials 2007 Volume 19(Issue 20) pp:3163-3166
Publication Date(Web):17 OCT 2007
DOI:10.1002/adma.200701975
A dopamine-PEG based ligand is synthesized and used to stabilize monodisperse 9 nm Fe3O4 nanoparticles in physiological conditions and against non-specific uptake by macrophage cells. Such stable nanoparticles can be used to enhance the efficiency in target-specific drug delivery and to increase the signal-to-noise ratio in magnetic resonance imaging (MRI).
Co-reporter:Chenjie Xu
Polymer International 2007 Volume 56(Issue 7) pp:
Publication Date(Web):28 FEB 2007
DOI:10.1002/pi.2251
Magnetic nanoparticles that are superparamagnetic with high saturation moment have great potential for biomedical applications. Solution-phase syntheses have recently been applied to make various kinds of monodisperse magnetic nanoparticles with standard deviation in diameter of less than 10%. However, the surface of these nanoparticles is coated with a layer of hydrocarbon molecules due to the use of lipid-like carboxylic acid and amine in the syntheses. Surface functionalization leads to the formation of water-soluble nanoparticles that can be further modified with various biomolecules. Such functionalization has brought about several series of monodisperse magnetic nanoparticle systems that have shown promising applications in protein or DNA separation, detection and magnetic resonance imaging contrast enhancement. The goal of this mini review is to summarize the recent progress in the synthesis and surface modification of monodisperse magnetic nanoparticles and their applications in biomedicine. Copyright © 2007 Society of Chemical Industry
Co-reporter:Sheng Peng
Angewandte Chemie 2007 Volume 119(Issue 22) pp:
Publication Date(Web):27 APR 2007
DOI:10.1002/ange.200700677
Die kontrollierte Oxidation amorpher Nanopartikel mit Fe-Kern und Fe3O4-Schale in Lösung führt zu monodispersen hohlen Fe3O4-Nanopartikeln, die sich zu Übergittern anordnen (siehe TEM-Bild). Dieses Verfahren eröffnet einen allgemeinen Zugang zu hohlen Eisenoxid- und Kern(Fe)-Schale(Fe3O4)-Hohlraum-Nanopartikeln für mögliche Anwendungen in der Katalyse und in elektromagnetischen Hochfrequenz-Funktionseinheiten.
Co-reporter:Yanglong Hou Dr.;Zhichuan Xu
Angewandte Chemie International Edition 2007 Volume 46(Issue 33) pp:
Publication Date(Web):23 JUL 2007
DOI:10.1002/anie.200701694
Shaping up for conversion: Monodisperse FeO nanoparticles were synthesized by reductive decomposition of iron(III) acetylacetonate with oleic acid (OA) and oleylamine (OAm). The nanoparticle sizes were tunable from 14 to 100 nm and their shapes were controlled to be either spherical or truncated octahedral (see images). The FeO nanoparticles were converted into diverse FexOy nanoparticles, which have potential in magnetic and catalytic applications.
Co-reporter:Chao Wang;Yanglong Hou Dr.;Jaemin Kim
Angewandte Chemie International Edition 2007 Volume 46(Issue 33) pp:
Publication Date(Web):22 JUN 2007
DOI:10.1002/anie.200702001
Length made to order: Controlled reduction of [Pt(acac)2] and decomposition of [Fe(CO)5] in a mixture of oleylamine and octadecene leads to the facile synthesis of FePt nanowires and nanorods with diameters of 2–3 nm (see TEM image). The length of the nanowires/nanorods is tunable from greater than 200 nm down to 20 nm by simply controlling the volume ratio of oleylamine and octadecene.
Co-reporter:Sheng Peng
Angewandte Chemie International Edition 2007 Volume 46(Issue 22) pp:
Publication Date(Web):27 APR 2007
DOI:10.1002/anie.200700677
Controlled oxidation of amorphous core–shell Fe–Fe3O4 nanoparticles in a simple solution-phase process affords monodisperse hollow Fe3O4 nanoparticles. Self-assembly of the monodisperse hollow Fe3O4 nanoparticles leads to superlattice arrays (see TEM image). The synthesis offers a general approach to hollow iron oxide and core–shell–void Fe–Fe3O4 nanoparticles that may have potential applications in catalysis and high-frequency electromagnetic devices.
Co-reporter:Chao Wang;Yanglong Hou Dr.;Jaemin Kim
Angewandte Chemie 2007 Volume 119(Issue 33) pp:
Publication Date(Web):22 JUN 2007
DOI:10.1002/ange.200702001
Länge auf Bestellung: Die kontrollierte Reduktion von [Pt(acac)2] und Zersetzung von [Fe(CO)5] in einer Mischung aus Oleylamin und Octadecen ermöglicht eine einfache Synthese von FePt-Nanodrähten und -Nanostäbchen mit Durchmessern von 2 bis 3 nm (siehe TEM-Bild). Die Länge der Nanodrähte/Nanostäbchen lässt sich einfach über das Volumenverhältnis von Oleylamin und Octadecen von mehr als 200 nm bis herunter zu 20 nm einstellen.
Co-reporter:Yanglong Hou Dr.;Zhichuan Xu
Angewandte Chemie 2007 Volume 119(Issue 33) pp:
Publication Date(Web):23 JUL 2007
DOI:10.1002/ange.200701694
In Form gebracht: Monodisperse FeO-Nanopartikel wurden durch reduktives Zersetzen von Eisen(III)-acetylacetonat mit Ölsäure (OA) und Oleylamin (OAm) hergestellt. Die Größe der Nanopartikel konnte zwischen 14 und 100 nm und ihre Form als kugelförmig oder gekappt-oktaedrisch (siehe Bilder) eingestellt werden. Die FeO-Nanopartikel wurden in eine Vielzahl von FexOy-Nanopartikeln überführt, die für magnetische und katalytische Anwendungen interessant sind.
Co-reporter:Chenjie Xu;Jin Xie;Don Ho;Chao Wang;Nathan Kohler Dr.;EdwardG. Walsh ;JeffreyR. Morgan ;Y.Eugene Chin
Angewandte Chemie 2007 Volume 120( Issue 1) pp:179-182
Publication Date(Web):
DOI:10.1002/ange.200704392
Co-reporter:Chenjie Xu;Jin Xie;Don Ho;Chao Wang;Nathan Kohler Dr.;EdwardG. Walsh ;JeffreyR. Morgan ;Y.Eugene Chin
Angewandte Chemie International Edition 2007 Volume 47( Issue 1) pp:173-176
Publication Date(Web):
DOI:10.1002/anie.200704392
Co-reporter:S. Sun
Advanced Materials 2006 Volume 18(Issue 4) pp:393-403
Publication Date(Web):24 JAN 2006
DOI:10.1002/adma.200501464
This paper reviews recent advances in chemical synthesis, self-assembly, and potential applications of monodisperse binary FePt nanoparticles. After a brief introduction to nanomagnetism and conventional processes of fabricating FePt nanoparticles, the paper focuses on recent developments in solution-phase syntheses of monodisperse FePt nanoparticles and their self-assembly into nanoparticle superlattices. The paper further outlines the surface, structural, and magnetic properties of the FePt nanoparticles and gives examples of three potential applications in data storage, permanent magnetic nanocomposites, and biomedicine.
Co-reporter:Chenjie Xu, Shouheng Sun
Advanced Drug Delivery Reviews (May 2013) Volume 65(Issue 5) pp:732-743
Publication Date(Web):1 May 2013
DOI:10.1016/j.addr.2012.10.008
Magnetic nanoparticles (MNPs) based on iron oxide, especially magnetite (Fe3O4), have been explored as sensitive probes for magnetic resonance imaging and therapeutic applications. Such application potentials plus the need to achieve high efficiency and sensitivity have motivated the search for new forms of superparamagnetic NPs with additional chemical and physical functionalities. This review summarizes the latest development of high moment MNPs, multifunctional MNPs, and porous hollow MNPs for biosensing, molecular imaging, and drug delivery applications.Download high-res image (213KB)Download full-size image
Co-reporter:Liheng Wu; Qing Li; Cheng Hao Wu; Huiyuan Zhu; Adriana Mendoza-Garcia; Bo Shen; Jinghua Guo
Journal of the American Chemical Society () pp:
Publication Date(Web):May 27, 2015
DOI:10.1021/jacs.5b04142
Monodisperse cobalt (Co) nanoparticles (NPs) were synthesized and stabilized against oxidation via reductive annealing at 600 °C. The stable Co NPs are active for catalyzing the oxygen evolution reaction (OER) in 0.1 M KOH, producing a current density of 10 mA/cm2 at an overpotential of 0.39 V (1.62 V vs RHE, no iR-correction). Their catalysis is superior to the commercial Ir catalyst in both activity and stability. These Co NPs are also assembled into a monolayer array on the working electrode, allowing the detailed study of their intrinsic OER activity. The Co NPs in the monolayer array show 15 times higher turnover frequency (2.13 s–1) and mass activity (1949 A/g) than the NPs deposited on conventional carbon black (0.14 s–1 and 126 A/g, respectively) at an overpotential of 0.4 V. These stable Co NPs are a promising new class of noble-metal-free catalyst for water splitting.
Co-reporter:Pinxian Xi, Kai Cheng, Xiaolian Sun, Zhengzhi Zeng and Shouheng Sun
Chemical Communications 2012 - vol. 48(Issue 24) pp:NaN2954-2954
Publication Date(Web):2012/01/23
DOI:10.1039/C2CC18122C
Magnetic 8 nm Fe3O4 nanoparticles (NPs) were synthesized and modified with dopamine (DPA) and polyethylene glycol (PEG) diacid. The water soluble Fe3O4–DPA–PEG NPs were then conjugated with the fluorescent Eu(III) complex of tris(dibenzoylmethane)-5-amino-1,10-phenanthroline (BMAP), giving an Fe3O4–DPA–PEG–BMAP–Eu NP conjugate. The conjugate was both colloidally and chemically stable in phosphate buffered solutions and could be used as a probe for magnetic resonance and fluorescent imaging.
Co-reporter:Zhong-Peng Lv, Tao Wang, Jing-Yuan Ge, Zhong-Zhi Luan, Di Wu, Jing-Lin Zuo and Shouheng Sun
Journal of Materials Chemistry A 2017 - vol. 5(Issue 29) pp:NaN7206-7206
Publication Date(Web):2017/06/30
DOI:10.1039/C7TC01021D
We report a solution phase based assembly method to tune the transport mechanism and magnetoresistance (MR) of Fe3O4 nanoparticles (NPs). The NP topological arrangement is altered by the NP coating of tetrathiafulvalene carboxylic acid (TTFCOOH) or its dicarboxylic analogue (TTF(COOH)2). Consequently, the transport mechanism of the assembly switches from tunneling to Mott hopping. The MR ratios of the Fe3O4 NP assemblies can be further tuned by the polarity of the solvent used in the ligand exchange process. The TTF(COO)2-coated Fe3O4 NP assembly has a 5% room temperature MR ratio, which is the highest value among all TTF-COO-Fe3O4 NP assemblies reported so far.
Co-reporter:Kaylie L. Young, Chenjie Xu, Jin Xie and Shouheng Sun
Journal of Materials Chemistry A 2009 - vol. 19(Issue 35) pp:NaN6406-6406
Publication Date(Web):2009/07/01
DOI:10.1039/B902373A
Monodisperse Fe3O4nanoparticles (NPs) originally synthesized with a hydrophobic oleylamine capping ligand were made water soluble and conjugated to the anticancer drug Methotrexate (MTX) using a new chemistry based on the readily available linker trichloro-s-triazine (TsT). This new linker is much more versatile than those that currently exist for attaching biomolecules to magnetic NPs. The MTX-conjugated NPs were found to be stable under physiological conditions for over 72 hours and MTX was shown to maintain its anticancer activity after conjugation to the NP surface. Through cell viability studies and intracellular uptake studies, MTX-conjugated NPs were shown to have targeting specificity for a tumor cell line (9L rat glioma) over a healthy cell line (Cultured Pulmonary Artery Endothelial). Additionally the MTX-conjugated NPs were visualized inside 9L cells using fluorescence microscopy to help elucidate their path within a cell after internalization.
Co-reporter:Pinxian Xi, Kai Cheng, Xiaolian Sun, Zhengzhi Zeng and Shouheng Sun
Journal of Materials Chemistry A 2011 - vol. 21(Issue 31) pp:NaN11467-11467
Publication Date(Web):2010/12/03
DOI:10.1039/C0JM03119D
A fluorescent ruthenium (Ru) complex is coupled to magnetic Fe3O4 nanoparticles (NPs) via3-(3,4-dihydroxyphenyl) propanoic acid (DHPPA) and O,O′-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (PPG-PEG-PPG-diamine). The resultant Ru–Fe3O4 NP conjugate shows excellent colloidal, photochemical and magnetic stability, and is promising as a dual functional probe for biological imaging applications.
Co-reporter:Hongwang Zhang, Sheng Peng, Chuan-bing Rong, J. Ping Liu, Ying Zhang, M. J. Kramer and Shouheng Sun
Journal of Materials Chemistry A 2011 - vol. 21(Issue 42) pp:NaN16876-16876
Publication Date(Web):2011/06/22
DOI:10.1039/C1JM11753J
We report a facile synthesis of ferromagnetic SmCo nanoparticles (NPs) via a controlled reduction of SmCo–O NPs. The SmCo–O NPs were prepared by co-precipitation of Co(II) and Sm(III) acetates with hexadecyl-trimethylammonium hydroxide and were embedded in a CaO matrix. The 7 nm SmCo3.6–O NPs were reduced by Ca at 960 °C and converted into ferromagnetic 6 nm SmCo5 NPs with their coercivities reaching 7.2 kOe. The synthesis provides a viable route to ferromagnetic SmCo NPs with controlled compositions and magnetism for high performance permanent magnetic applications.
Co-reporter:Yi Liu, Dongguo Li and Shouheng Sun
Journal of Materials Chemistry A 2011 - vol. 21(Issue 34) pp:NaN12587-12587
Publication Date(Web):2011/06/28
DOI:10.1039/C1JM11605C
This feature article highlights the recent advances in the synthesis of Pt-based binary alloy and core–shell nanoparticles (NPs) for magnetic, catalytic and biomedical applications. These composite NPs are made by thermal decomposition and reduction of metal precursors in a high boiling point organic solvent with their size, shape, composition and shell thickness controlled by metal precursor concentrations, surfactant concentrations and reaction temperatures. The as-synthesized alloy NPs adopt typically the face centered cubic (fcc) structure and can be further converted into the face centered tetragonal (fct) structure upon high temperature annealing. The NP size, shape, composition and structure dependent magnetism and catalysis are further illustrated. The studies show that the fct structured NPs are ferromagnetic and are promising components for magnetic data storage media, and that the core–shell NPs are better catalysts for fuel cell reactions with much enhanced activity and durability, and that the fcc structured FePt NPs have great potential for multimodality imaging and for therapeutic applications.
Co-reporter:Chenjie Xu and Shouheng Sun
Dalton Transactions 2009(Issue 29) pp:NaN5591-5591
Publication Date(Web):2009/05/01
DOI:10.1039/B900272N
Superparamagnetic nanoparticles (NPs) have been attractive for medical diagnostics and therapeutics due to their unique magnetic properties and their ability to interact with various biomolecules of interest. The solution phase based chemical synthesis provides a near precise control on NP size, and monodisperse magnetic NPs with standard deviation in diameter of less than 10% are now routinely available. Upon controlled surface functionalization and coupling with fragments of DNA strands, proteins, peptides or antibodies, these NPs can be well-dispersed in biological solutions and used for drug delivery, magnetic separation, magnetic resonance imaging contrast enhancement and magnetic fluid hyperthermia. This Perspective reviews the common syntheses and controlled surface functionalization of monodisperse Fe3O4-based superparamagnetic NPs. It further outlines the exciting application potentials of these NPs in magnetic resonance imaging and drug delivery.
Co-reporter:Natalie A. Frey, Sheng Peng, Kai Cheng and Shouheng Sun
Chemical Society Reviews 2009 - vol. 38(Issue 9) pp:NaN2542-2542
Publication Date(Web):2009/06/23
DOI:10.1039/B815548H
This tutorial review summarizes the recent advances in the chemical synthesis and potential applications of monodisperse magnetic nanoparticles. After a brief introduction to nanomagnetism, the review focuses on recent developments in solution phase syntheses of monodisperse MFe2O4, Co, Fe, CoFe, FePt and SmCo5 nanoparticles. The review further outlines the surface, structural, and magnetic properties of these nanoparticles for biomedicine and magnetic energy storage applications.
Co-reporter:Hongfeng Yin, Chao Wang, Haoguo Zhu, Steven H. Overbury, Shouheng Sun and Sheng Dai
Chemical Communications 2008(Issue 36) pp:NaN4359-4359
Publication Date(Web):2008/07/25
DOI:10.1039/B807591C
Highly active Au catalysts with a dumbbell-like heterostructure for CO oxidation were prepared through colloidal deposition method; both activities and stabilities were investigated under different experimental conditions.
Co-reporter:Rui Hao, Jing Yu, Yanglong Hou and Shouheng Sun
Chemical Communications 2011 - vol. 47(Issue 32) pp:NaN9097-9097
Publication Date(Web):2011/07/04
DOI:10.1039/C1CC12759D
A general one-pot protocol is reported to prepare hollow or porous manganese (Mn) oxide, phosphate, sulfide nanoparticles (NPs) via a controlled ion transfer process.
Co-reporter:Jonghun Lee ; Melissa A. Petruska
The Journal of Physical Chemistry C () pp:
Publication Date(Web):
DOI:10.1021/jp502361d
In a solution-phase synthesis of nanocrystals (NCs), organic surfactants play an important role in size and shape control as well as in facilitating the stable dispersion of NCs in solvents. However, in order to use these NCs for electrical applications, the surfactants must be removed effectively. Here we report that monodisperse indium tin oxide (ITO) NCs were synthesized and stabilized with oleate/oleylamine ligands, and these long-chain surfactants were readily substituted with tetrabutylammonium hydroxide (TBAOH), forming a stable methanol dispersion. Uniform assemblies of ITO NCs were made by spin-coating the ITO–TBAOH NC dispersions with an assembly thickness controllable from 68 to 260 nm by the NC solution concentration. An annealing treatment at 120 °C and 300 °C under Ar + 5% H2 for 1 h effectively removed the TBAOH, and the ITO NC assemblies showed high transparency (>88%) and low resistivity (2.6 × 10–3 Ω·cm). Our new approach to surface modification of ITO NCs with a volatile surfactant followed by film deposition is an effective strategy for fabricating ITO NC films by a solution process with desired transparency and conductivity for transparent electrode applications.
