Co-reporter:Gengtao Fu, Ke Wu, Jun Lin, Yawen Tang, Yu Chen, Yiming Zhou, and Tianhong Lu
The Journal of Physical Chemistry C May 16, 2013 Volume 117(Issue 19) pp:9826-9834
Publication Date(Web):April 13, 2013
DOI:10.1021/jp400502y
Well-defined and strikingly monomorphic Pt–Pd alloy nanoflowers (Pt–Pd ANFs) with dominant {111} facets were successfully synthesized through a facile cochemical reduction method in a poly(allylamine hydrochloride) (PAH) based aqueous solution. The detailed morphology, composition, and structure of the Pt–Pd ANFs were investigated by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy dispersive spectrum (EDS), nitrogen adsorption–desorption isotherms (SADI), EDS mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), demonstrating the Pt–Pd ANFs were highly porous and a self-supported structure. The formation mechanism of the Pt–Pd ANFs were investigated by TEM and Fourier transform infrared (FT-IR), indicating that the existence of PAH and rapid growth of crystal nuclei were essential for the formation of the Pt–Pd ANFs. The electrocatalytic activity and stability of the Pt–Pd ANFs for the oxygen reduction reaction (ORR) were investigated by rotating disk electrode voltammetry in 0.1 M HClO4 solution. The electrochemical tests indicated the {111}-enclosed Pt–Pd ANFs exhibited superior ORR activity along with satisfactory stability and methanol-tolerant ability under acidic conditions, which made them promising electrocatalysts for the future.
Co-reporter:Dr. Xinyu Liu;Gengtao Fu; Yawen Tang;Peiliang She ;Tianhong Lu
Chemistry - A European Journal 2014 Volume 20( Issue 2) pp:585-590
Publication Date(Web):
DOI:10.1002/chem.201302834
Abstract
Pt alloy nanostructures show great promise as electrocatalysts for the oxygen reduction reaction (ORR) in fuel cell cathodes. Herein, three-dimensional (3D) Pt-Pd-Co trimetallic network nanostructures (TNNs) with a high degree of alloying are synthesized through a room temperature wet chemical synthetic method by using K2PtCl4/K3Co(CN)6–K2PdCl4/K3Co(CN)6 mixed cyanogels as the reaction precursor in the absence of surfactants and templates. The size, morphology, and surface composition of the Pt-Pd-Co TNNs are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy dispersive spectroscopy (EDS), EDS mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The 3D backbone structure, solid nature, and trimetallic properties of the mixed cyanogels are responsible for the 3D structure and high degree of alloying of the as-prepared products. Compared with commercially available Pt black, the Pt-Pd-Co TNNs exhibit superior electrocatalytic activity and stability towards the ORR, which is ascribed to their unique 3D structure, low hydroxyl surface coverage and alloy properties.
Co-reporter:Pan Li, Yu Ding, Ao Wang, Lin Zhou, Shaohua Wei, Yiming Zhou, Yawen Tang, Yu Chen, Chenxin Cai, and Tianhong Lu
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 6) pp:2255
Publication Date(Web):March 2, 2013
DOI:10.1021/am400152k
In this work, the soluble cobalt phthalocyanine functionalized multiwalled carbon nanotubes (MWCNTs) are synthesized by π–π stacking interaction between tetrakis (3-trifluoromethylphenoxy) phthalocyaninato cobalt(II) (CoPcF) complex and MWCNTs. The physical properties of CoPcF-MWCNTs hybrids are evaluated using spectroscopy (UV–vis, XPS, and Raman) and electron microscopy (TEM and SEM). Subsequently, an amperometric nitrite electrochemical sensor is designed by immobilizing CoPcF-MWCNTs hybrids on the glassy carbon electrode. The immobilized CoPcF complex shows the fast electron transfer rate and excellent electrocatalytic activity for the oxidation of nitrite. Under optimum experimental conditions, the proposed nitrite electrochemical sensor shows the fast response (less than 2 s), wide linear range (9.6 × 10–8 to 3.4 × 10–4 M) and low detection limit (6.2 × 10–8 M) because of the good mass transport, fast electron transfer rate, and excellent electrocatalytic activity.Keywords: carbon nanotubes; cobalt phthalocyanine; electrocatalysis; nitrite; sensor;
Co-reporter:Hailing Liu, Yanyun Cui, Pan Li, Yiming Zhou, Yu Chen, Yawen Tang, Tianhong Lu
Analytica Chimica Acta 2013 Volume 776() pp:24-30
Publication Date(Web):7 May 2013
DOI:10.1016/j.aca.2013.03.040
•The ionotropic crosslinking interactions result in the coacervation of chitosan.•A phosphonate-assisted encapsulation of proteins in chitosan matrix is introduced.•The encapsulated proteins retain their bioactivity.•The encapsulation method can be used to fabricate various chitosan-based biosensors.Based on the polyphosphonate-assisted coacervation of chitosan, a simple and versatile procedure for the encapsulation of proteins/enzymes in chitosan–carbon nanotubes (CNTs) composites matrix was developed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrum (EDS) mapping demonstrated the hemoglobin (Hb) uniformly distributed into chitosan–CNTs composites matrix. Raman measurements indicated the CNTs in composites matrix retained the electronic and structural integrities of the pristine CNTs. Fourier transform infrared (FT-IR), ultraviolet–visible (UV–vis) and circular dichroism (CD) spectroscopy displayed the encapsulated Hb preserved their near-native structure, indicating the polyphosphonate–chitosan–CNTs composites possessed excellent biocompatibility for the encapsulation of proteins/enzymes. Electrochemical measurements indicated the encapsulated Hb could directly exchange electron with the substrate electrode. Moreover, the modified electrode showed excellent bioelectrocatalytic activity for the reduction of hydrogen peroxide. Under optimum experimental conditions, the fabricated electrochemical sensor displayed the fast response (less than 3 s), wide linear range (7.0 × 10−7 to 2.0 × 10−3 M) and low detection limit (4.0 × 10−7 M) for the determination of hydrogen peroxide. This newly developed protocol was simple and mild and would certainly find extensive applications in biocatalysis, biosensors, bioelectronics and biofuel cells.Based on the coacervation of chitosan via the ionotropic crosslinking interaction, proteins/enzymes can be encapsulated in situ into chitosan matrix.
Co-reporter:Lu Zhang, Qi Sui, Tingting Tang, Yu Chen, Yiming Zhou, Yawen Tang, Tianhong Lu
Electrochemistry Communications 2013 Volume 32() pp:43-46
Publication Date(Web):July 2013
DOI:10.1016/j.elecom.2013.03.041
•Pd nanodendrite assemblies (Pd-NDAs) are obtained by a cyanogel-reduction route.•The BET surface area of the Pd-NDAs is measured to be 90.1 m2 g− 1.•Pd-NDAs exhibit enhanced activity and stability for the formic acid oxidation.Well-defined Pd nanodendrite assemblies (Pd-NDAs) with high surface area are successfully synthesized through a facile cyanogel-reduction route in the absence of surfactant. The detailed morphology, composition and structure of the Pd-NDAs are thoroughly investigated by various characterization methods, demonstrating that the Pd-NDAs are highly porous and self-supported structures. Cyclic voltammetry, CO-stripping and chronoamperometry tests show that the Pd-NDAs exhibit superior electrocatalytic activity and stability for the formic acid oxidation under acidic conditions, which make them promising anodic electrocatalysts for the future.Well-defined Pd nanodendrite assemblies with big surface area and high electrocatalytic activity were fabricated though simple cyanogel-reduction method.
Co-reporter:Gengtao Fu, Ke Wu, Xian Jiang, Lin Tao, Yu Chen, Jun Lin, Yiming Zhou, Shaohua Wei, Yawen Tang, Tianhong Lu and Xinghua Xia
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 11) pp:3793-3802
Publication Date(Web):10 Jan 2013
DOI:10.1039/C3CP44191A
The synthesis of Pt nanocrystals with controlled size and morphology has drawn enormous interest due to their particular catalytic activity. We present a facile and green hydrothermal method for synthesizing monodisperse Pt nanocubes (Pt-NCs) with polyallylamine hydrochloride (PAH) as a complex-forming agent, capping agent and facet-selective agent, and formaldehyde as a reductant. The formation mechanism, particle size and surface composition of the Pt-NCs were investigated by Ultraviolet and visible spectroscopy (UV-vis), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), etc. In the proposed PAH–K2PtCl4–HCHO synthesis system, the raw material could be reutilized to re-synthesize the Pt-NCs, and the particle size of the Pt-NCs could be readily controlled by the reduction rate of the PtII species in the PtII–PAH complex. After UV/Ozone and electrochemical cleaning, the residual PAH on the Pt-NC surfaces still strongly influenced the d-band centre of Pt due to the strong N–Pt interaction. The as-prepared 6 nm Pt-NCs showed superior electrocatalytic activity (mass activity and specific activity) and stability towards the oxygen reduction reaction (ORR) in both H2SO4 and HClO4 electrolytes compared to the commercial E-TEK Pt black, owing to the combination of the facets effect and electronic effect.
Co-reporter:Hailing Liu, Yanyun Cui, Pan Li, Yiming Zhou, Xiaoshu Zhu, Yawen Tang, Yu Chen and Tianhong Lu
Analyst 2013 vol. 138(Issue 9) pp:2647-2653
Publication Date(Web):26 Feb 2013
DOI:10.1039/C3AN00113J
A nonenzymatic iron(III) diethylenetriaminepentaacetic acid (FeIII-DETPA) complex based amperometric sensor for the analytical determination of hydrogen peroxide was developed. By combining the electrostatic interaction between the FeIII-DETPA complex and polyallylamine (PAH) functionalized multiwalled carbon nanotubes (MWCNTs) as well as the ionotropic crosslinking interaction between PAH and ethylenediamine-tetramethylene phosphonic acid (EDTMP), the electroactive FeIII-DETPA complex was successfully incorporated within the MWCNT matrix, and firmly immobilized on the Au substrate electrode. The fabricated electrochemical sensor was characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical methods. The influences of solution pH and ionic strength on the electrochemical sensor were investigated. The prepared electrochemical sensor had a fast response to hydrogen peroxide (<3 s) and an excellent linear range of concentration from 1.25 × 10−8 to 4.75 × 10−3 M with a detection limit of 6.3 × 10−9 M under the optimum conditions.
Co-reporter:Gengtao Fu, Xian Jiang, Lin Tao, Yu Chen, Jun Lin, Yiming Zhou, Yawen Tang, and Tianhong Lu
Langmuir 2013 Volume 29(Issue 13) pp:4413-4420
Publication Date(Web):March 12, 2013
DOI:10.1021/la304881m
Polyallylamine (PAH) functionalized Pd icosahedra are synthesized through a simple, one-pot, seedless and hydrothermal growth method. Herein, PAH is used efficiently as a complex-forming agent, capping agent, and facet-selective agent. The strong interaction between PAH and Pd atom sharply changes the electronic structure of Pd atom in the Pd icosahedra. The protective function of PAH layers and enhanced antietching capability of Pd atom are responsible for the formation of the Pd icosahedra. Very importantly, the as-prepared PAH functionalized Pd icosahedra exhibit superior electrocatalytic activity and ethanol tolerant ability toward the oxygen reduction reaction (ORR) compared to the commercially available Pt black in alkaline media. At 0.95 V (vs RHE), the ORR specific kinetic current density at the Pd icosahedra is 4.48 times higher than that at commercial Pt black. The fact demonstrates the appropriate surface modification of the Pd nanoparticles by nonmetallic molecules can be regarded as an effective way to enhance the electrocatalytic activity toward the ORR.
Co-reporter:Jiangfeng Xu, Xinyu Liu, Yu Chen, Yiming Zhou, Tianhong Lu and Yawen Tang
Journal of Materials Chemistry A 2012 vol. 22(Issue 44) pp:23659-23667
Publication Date(Web):09 Oct 2012
DOI:10.1039/C2JM35649J
Three-dimensional (3D) platinum–cobalt alloy networks nanostructures with a high alloying degree were synthesized through a room temperature wet-chemical synthetic method using the K2PtCl4/K3Co(CN)6 cyanogel as reaction precursor in the absence of surfactants and templates. The size, morphology and surface composition of platinum–cobalt alloy networks nanostructures were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), selected area electron diffraction (SAED), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The 3D backbone structure and double-metallic property of the K2PtCl4/K3Co(CN)6 cyanogel are responsible for the 3D structure and the high alloying degree of the as-prepared products, respectively. Compared to the pure Pt nanoparticles, 3D platinum–cobalt alloy networks nanostructures exhibit superior electrocatalytic activity and stability for the methanol oxidation reaction (MOR), which is ascribed to their unique 3D structure and alloy properties.
Co-reporter:Gengtao Fu, Wei Han, Lifang Yao, Jun Lin, Shaohua Wei, Yu Chen, Yawen Tang, Yiming Zhou, Tianhong Lu and Xinghua Xia
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:17604-17611
Publication Date(Web):09 Jul 2012
DOI:10.1039/C2JM32381H
We report a facile methodology for one-step synthesis of the porous palladium nanospheres (Pd-NSS) using polyallylamine hydrochloride (PAH) as the complex-forming agent and stabilizing agent under mild reaction conditions (35 °C). The size, integrity, nature and composition of the Pd-NSS are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–adsorption experiments, energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), zeta potential, ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infrared spectroscopy (FT-IR), etc. These spectral studies confirm that the PAH functionalized Pd-NSS are three-dimensionally interconnected porous nanostructures with primary nanoparticles as building blocks. Further experiential investigations show that the particle size of the Pd-NSS can be readily controlled by altering the ratio of PdCl2 to PAH during synthesis, and the Pd-NSS possess high catalytic activity and good stability for the Mizoroki–Heck reaction.
Co-reporter:Pan Li, Hailing Liu, Yu Ding, Yi Wang, Yu Chen, Yiming Zhou, Yawen Tang, Haiyan Wei, Chenxin Cai and Tianhong Lu
Journal of Materials Chemistry A 2012 vol. 22(Issue 30) pp:15370-15378
Publication Date(Web):11 Jun 2012
DOI:10.1039/C2JM31350B
A facile noncovalent approach is proposed to graft phosphonate groups onto the surface of single-walled carbon nanotubes (SWNTs) by π–π stacking interactions between naphthalen-1-ylmethylphosphonic acid (NYPA) and SWNTs. Ultraviolet-visible (UV-vis) spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR) spectroscopy and zeta potential analysis confirm the phosphonate groups noncovalently attach on the SWNTs surface, in accordance with the prediction of molecular dynamics (MD) simulations. The phosphonate functionalized SWNTs have good solubility in polar solvent due to the big electrostatic repulsion between phosphonate groups, the strong hydration force of phosphonate groups and the partial debundling of SWNTs. X-ray diffraction (XRD) and Raman spectroscopy measurements demonstrate the water-soluble phosphonate functionalized SWNTs almost completely preserve the electronic and structural integrity of the pristine SWNTs. Meanwhile, the as-prepared phosphonate functionalized SWNTs show good biocompatibility for protein immobilization. Consequently, myoglobin (Mb) proteins immobilized on the phosphonate functionalized SWNTs show excellent bioelectrocatalytic activity towards the reduction of hydrogen peroxide due to the exciting electronic properties of the phosphonate functionalized SWNTs and the fast electron transfer rate of Mb.
Co-reporter:Jiangfeng Xu, Gengtao Fu, Yawen Tang, Yiming Zhou, Yu Chen and Tianhong Lu
Journal of Materials Chemistry A 2012 vol. 22(Issue 27) pp:13585-13590
Publication Date(Web):16 May 2012
DOI:10.1039/C2JM32012F
Three-dimensional platinum nanochain network (Pt-3NCNW) nanostructures are synthesized through a thermal decomposition method using platinum(IV)-complexes as reaction precursors in the absence of surfactants and templates. The size, morphology and surface composition of Pt-3NCNWs are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). These spectral studies confirm the as-papered products are three-dimensionally interconnected network nanostructures with primary Pt nanochains as building blocks, and the Pt nanochains grow from the primary spheric Pt nanoparticles via oriented attachment. Compared to the commercial Pt black catalyst, the Pt-3NCNW nanostructures exhibit superior electrocatalytic activity and stability towards oxygen reduction reactions, which is ascribed to their unique properties such as the few surface defect sites and the low hydroxyl surface coverage on one-dimensional Pt nanochains, as well as fast O2 diffusion in three-dimensional structures.
Co-reporter:Ke Wu, Xinbiao Mao, Yan Liang, Yu Chen, Yawen Tang, Yiming Zhou, Jun Lin, Chunan Ma, Tianhong Lu
Journal of Power Sources 2012 Volume 219() pp:258-262
Publication Date(Web):1 December 2012
DOI:10.1016/j.jpowsour.2012.07.059
Multiwalled carbon nanotubes (MWCNTs) supported palladium-phosphorus nanoparticles (Pd–P/MWCNTs) catalyst is synthesized by homogeneous precipitation–reduction reaction method using hypohosphite as reducing agent. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis confirm that some P has entered into the crystal lattice of Pd and thus the Pd–P alloy is formed. Transmission electron microscopy (TEM) images reveal that Pd–P nanoparticles are uniformly dispersed on MWCNTs and the average particle size of Pd–P/MWCNTs catalyst is very similar to that of Pd/MWCNTs catalyst prepared by using NaBH4 as reducing agent. Cyclic voltammetric and chronoamperometric experiments show that the electrocatalytic activity and long-term operation stability of Pd–P/MWCNTs catalyst are better than that of Pd/MWCNTs catalyst for ethanol electrooxidation in alkaline media, indicating that the addition of P in Pd nanoparticles can promote the electrocatalytic activity and stability of Pd catalyst for ethanol electrooxidation.Highlights► Pd–P/MWCNTs is synthesized by homogeneous precipitation–reduction reaction method. ► Ultrafine Pd–P nanoparticles are highly dispersed on MWCNTs surface. ► Pd–P/MWCNTs shows excellent electrocatalytic activity for ethanol oxidation.
Co-reporter:Hanjun Sun, Jiangfeng Xu, Gengtao Fu, Xinbiao Mao, Lu Zhang, Yu Chen, Yiming Zhou, Tianhong Lu, Yawen Tang
Electrochimica Acta 2012 Volume 59() pp:279-283
Publication Date(Web):1 January 2012
DOI:10.1016/j.electacta.2011.10.092
Highly dispersed and ultrafine palladium–phosphorus (Pd–P) nanoparticles (NPs) are prepared with a novel phosphorus reduction method. The structural and electronic properties of Pd–P NPs are characterized using Fourier transform infrared (FT-IR), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrooxidation of formic acid on Pd–P NPs are investigated by using cyclic voltammetry, chronoamperometry and CO-stripping measurements. The physical characterizations indicate the doped P element can enhance the content of Pd0 species in Pd NPs, decrease the particle size and improve the dispersion of Pd–P NPs. The electrochemical measurements show the Pd–P NPs have a better catalytic performance for formic acid electrooxidation than Pd NPs.
Co-reporter:Min Zheng, Pan Li, Chen Yang, Hui Zhu, Yu Chen, Yawen Tang, Yiming Zhou and Tianhong Lu
Analyst 2012 vol. 137(Issue 5) pp:1182-1189
Publication Date(Web):06 Jan 2012
DOI:10.1039/C2AN15957K
A fast, simple square wave potential method is developed for the fabrication of a three-dimensional (3D) nanoporous gold (NPG) film. The nanostructures are characterized and confirmed by scanning electronic microscopy (SEM) and cyclic voltammetry (CV). The nanostructures modified with self-assembled monolayers (SAMs) are employed as an electrode substrate to immobilize inorganic iron(III) ion. After immobilization, iron(III) ion undergoes an effective direct electron transfer reaction with a pair of well-defined redox peak at −256 ± 10 mV (pH 7.0). The iron(III) ion modified electrode displays the excellent electrocatalytic performance for reduction of hydrogen peroxide, and thus can be used as an electrochemical sensor for detecting hydrogen peroxide with a low detection limit (1.0 × 10−9 M), a wide linear range (9.0 × 10−7∼5.0 × 10−4 M), as well as good stability, selectivity and reproducibility.
Co-reporter:Yu Pan, Fan Zhang, Ke Wu, Zhaoyang Lu, Yu Chen, Yiming Zhou, Yawen Tang, Tianhong Lu
International Journal of Hydrogen Energy 2012 Volume 37(Issue 4) pp:2993-3000
Publication Date(Web):February 2012
DOI:10.1016/j.ijhydene.2011.11.042
Carbon supported Palladium–Iron bimetallic nanoparticles (Pd–Fe/C) electrocatalyst is synthesized by the direct thermal decomposition method of nontoxic metallic acetate salt. During the preparation of the Pd–Fe/C electrocatalyst, the tedious wash post-treatment of electrocatalyst is effectively avoided due to non-existence of inorganic anion. The physico-chemical properties of the Pd–Fe/C electrocatalyst are characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). These structural analyses reveal that the Pd–Fe/C electrocatalyst possesses the high alloying degree and the small particle size. Electrochemical data indicate that the eletrocatalytic activity of the Pd–Fe/C electrocatalyst for oxygen reduction reaction (ORR) is much higher than that of Pd/C electrocatalyst, which originates from the synergistic effect between Pd atom and Fe atom.Carbon supported Pd–Fe bimetallic nanoparticles with relatively small particle size were prepared by a direct thermal decomposition method of metallic acetate salt. HRTEM images show no obvious lattice fringe is found in Pd–Fe nanoparticles, indicating Fe atom has entered into the Pd crystal lattice and form a single-phase fcc disordered alloyed structure (solid solution).Highlights► A novel direct thermal decomposition method is used to prepare Pd–Fe/C bimetallic electrocatalyst. ► The tedious wash post-treatment of electrocatalyst is effectively avoided due to non-existence of inorganic anion. ► The resulting Pd–Fe/C electrocatalyst shows an excellent electrocatalytic activity for the ORR.
Co-reporter:Jiangfeng Xu, Xingyu Wu, Gengtao Fu, Xinyu Liu, Yu Chen, Yiming Zhou, Yawen Tang, Tianhong Lu
Electrochimica Acta 2012 80() pp: 233-239
Publication Date(Web):
DOI:10.1016/j.electacta.2012.07.005
Co-reporter:Guojie Zhang;Lu Zhang;Liping Shen;Dr. Yu Chen;Yiming Zhou;Dr. Yawen Tang;Tianhong Lu
ChemPlusChem 2012 Volume 77( Issue 10) pp:936-940
Publication Date(Web):
DOI:10.1002/cplu.201200163
Abstract
An inorganic polymeric hydrogel, which is formed irreversibly in water through interaction between K2PdIICl4 and K4FeII(CN)6, is synthesized. The palladium nanostructures take the form of three-dimensional (3D) networks and are obtained in a facile manner by simple reduction of the hydrogel using NaBH4. The size, morphology, and surface composition of these 3D palladium networks are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The electrochemical properties are investigated in detail by cyclic voltammetry, chronoamperometry, and CO stripping tests. Such 3D nanostructures exhibit a large electroactive surface area, excellent electrochemical stability, and high electrocatalytic activity toward electrooxidation of formic acid.
Co-reporter:Fan Zhang;Lu Zhang;Junfei Xing;Yawen Tang;Dr. Yu Chen;Yiming Zhou;Tianhong Lu;Dr. Xinghua Xia
ChemPlusChem 2012 Volume 77( Issue 10) pp:914-922
Publication Date(Web):
DOI:10.1002/cplu.201200137
Abstract
The sulphydryl-functionalized multiwalled carbon nanotubes (MWCNT-SH) are synthesized by π–π stacking interaction between 2-naphthalenethiol (NAT) and multiwalled carbon nanotubes (MWCNT). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy confirm sulphydryl groups attach on MWCNT surface. Meanwhile, the phosphate-functionalized gold nanoparticles (AuP–NPs) are obtained by using an improved phosphorus reduction method. On the basis of the AuS bond interaction between MWCNT-SH and AuP–NPs, the all-solid-state multilayered nanostructures of MWCNT/AuP–NPs are readily formed onto an electrode surface by using the layer-by-layer (LBL) self-assembly method. Transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV/Vis), scanning electron microscopy (SEM), and cyclic voltammetry (CV) are used to characterize the film assembly process. Electrochemical investigations demonstrate that the assembled nanostructures films possess excellent electrocatalytic activity toward hydrazine oxidation as a result of the “clean” surface of AuP–NPs, and thus can be used as an electrochemical sensor for hydrazine detection with the wide linear range (6.0×10−7 to 9.0×10−3 M) and the low detection limit (2.0×10−7 M). This demonstration offers a new route to synthesis of CNTs/metal–NPs multilayered films, which is believed to be useful for the fundamental investigations of CNTs/metal–NPs nanohybrids and their possible applications.
Co-reporter:Jiayue Zhao, Mengna Zhu, Min Zheng, Yawen Tang, Yu Chen, Tianhong Lu
Electrochimica Acta 2011 Volume 56(Issue 13) pp:4930-4936
Publication Date(Web):1 May 2011
DOI:10.1016/j.electacta.2011.03.014
Pd nanoparticle catalysts supported by multiwall carbon nanotubes (Pd/MWNTs) prepared using a complexation–reduction method are used in this study for the electrochemical determination of hydrazine. The physico-chemical properties of the Pd/MWNT catalyst were characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and scanning electron microscopy physico-chemical (SEM). These structural analyses reveal that the Pd/MWNTs-modified glassy carbon electrode possesses a three-dimensional network structure in which the Pd nanoparticles, with an average size of 5 nm, are uniformly distributed on the surface of the MWNTs. After Nafion solution was coated on the surface of the Pd/MWNT layer, the resulting Pd/MWNT–Nafion modified electrode retained the three-dimensional network structure. Electrochemical measurements show that the oxidation peak current of hydrazine decreases with increasing pH. Under optimum conditions, the Pd/MWNT–Nafion-based hydrazine sensor exhibits a broad linear calibration range (2.5–700 μM) and a low detection limit of 1.0 μM for hydrazine.Highlights► Pd/MWNTs catalyst with high activity is prepared by simple complexing−reduction method. ► Electrochemical measurements display that solution pH affects the oxidation of hydrazine. ► Pd/MWNTs−Nafion based hydrazine sensor displays a wide linear calibration range.
Co-reporter:Yan Liang, Mengna Zhu, Juan Ma, Yawen Tang, Yu Chen, Tianhong Lu
Electrochimica Acta 2011 Volume 56(Issue 12) pp:4696-4702
Publication Date(Web):30 April 2011
DOI:10.1016/j.electacta.2011.03.019
The highly dispersed and ultrafine carbon-supported Pd nanoparticles (Pd/C) catalyst is synthesized by using an improved precipitation–reduction method, which involves in PdII → PdO·H2O → Pd0 reaction path. In the method, palladium oxide hydrate (PdO·H2O) nanoparticles (NPs) with high dispersion is obtained easily by adjusting solution pH in the presence of 1,4-butylenediphosphonic acid (H2O3P-(CH2)4-PO3H2, BDPA). After NaBH4 reduction, the resulting Pd/C catalyst possesses high dispersion and small particle size. As a result, the electrochemical measurements indicate that the resulting Pd/C catalyst exhibits significantly high electrochemical active surface area and high electrocatalytic performance for formic acid electrooxidation compared with that prepared by general NaBH4 reduction method.Highlights► The dispersion of PdO·H2O nanoparticles on the carbon surface is the vital premise for preparation of Pd/C catalyst with high dispersion. ► PdO·H2O nanoparticles with high dispersion and small particle size can easily be obtained in the presence of 1,4-butylenediphosphonic acid (H2O3P-(CH2)4-PO3H2), which results in the formation of Pd/C catalyst with high dispersion. ► Electrochemical measurements indicate that the Pd/C catalyst prepared by the precipitation−reduction method exhibits high electrochemical active surface area and electrocatalytic performance for formic acid electrooxidation.
Co-reporter:Juan Ma, Yigang Ji, Hanjun Sun, Yu Chen, Yawen Tang, Tianhong Lu, Junwei Zheng
Applied Surface Science 2011 Volume 257(Issue 24) pp:10483-10488
Publication Date(Web):1 October 2011
DOI:10.1016/j.apsusc.2011.07.007
Abstract
A highly dispersed and ultrafine carbon supported Pd nanoparticles (Pd/C) catalyst is synthesized by a facile homogeneous precipitation-reduction reaction method. Under the appropriate pH conditions, [PdCl4]2− species in PdCl2 solution are slowly transformed into the insoluble palladium oxide hydrate (PdO·H2O) precipitation by heat treatment due to a slow hydrolysis reaction, which results in the generation of carbon supported PdO·H2O nanoparticles (PdO·H2O/C) sample with the high dispersion and small particle size. Consequently, a highly dispersed and ultrafine Pd/C catalyst can be synthesized by PdO·H2O → Pd0 in situ reduction reaction path in the presence of NaBH4. As a result, the resulting Pd/C catalyst possesses a significantly electrocatalytic performance for formic acid electrooxidation, which is attributed to the uniformly sized and highly dispersed nanostructure.
Co-reporter:Yu Chen, Yiming Zhou, Yawen Tang, Tianhong Lu
Journal of Power Sources 2010 Volume 195(Issue 13) pp:4129-4134
Publication Date(Web):1 July 2010
DOI:10.1016/j.jpowsour.2010.01.054
A series of carbon-supported bimetallic Pt-Ru catalysts with high alloying degree and different Pt/Ru atomic ratio have been prepared by a chemical reduction method in the H2O/ethanol/tetrahydrofuran (THF) mixture solvent. The structural and electronic properties of catalysts are characterized using X-ray reflection (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). The electrooxidation of formic acid on these Pt-Ru nanoparticles are investigated by using cyclic voltammetry, chronoamperometry and CO-stripping measurements. The results of electrochemical measurements illustrate that the alloying degree and Pt/Ru atomic ratio of Pt-Ru catalyst play an important role in the electrocatalytic activity of the Pt-Ru/C catalyst for formic acid electrooxidation due to the bifunctional mechanism and the electronic effect. Since formic acid is an intermediate in the methanol electrooxidation on Pt electrode in acidic electrolyte, the observation provides an additional fundamental understanding of the structure–activity relationship of Pt-Ru catalyst for methanol electrooxidation.
Co-reporter:Yu Chen, Chen Yang, Feng-Bin Wang
Electrochimica Acta 2010 Volume 55(Issue 12) pp:3951-3956
Publication Date(Web):30 April 2010
DOI:10.1016/j.electacta.2010.02.047
Binary thiolates self-assembled monolayers (SAMs) on gold have been prepared efficiently by using an electrochemical oxidation combining with replacement reaction method. The electrochemical results show that both the SAMs of mercaptoacetic acid (MAA) and 1-dodecanethiol (DT) on gold surface are oxidized at certain anodic potentials (noting: it is not oxidative redeposition of alkanethiolate monolayers on gold surface), and the degree of electrochemical oxidation of single thiolates-SAMs is function of the polarization potential and polarization time. Therefore, formation of binary MAA–DT thiolates-SAMs can be achieved if MAA or DT is present in solution after the electrochemical oxidation of DT or MAA SAMs on gold electrode. In this case, the ratio of MAA to DT on the binary thiolates-SAMs can be easily controlled by controlling polarization potential and/or polarization time. The present approach enables us to prepare homogeneously binary SAMs with different composition, and assess the electrochemical oxidation stability of single thiolates-SAMs by means of cyclic voltammetry measurements of redox probe.
Co-reporter:Min Zheng, Yue Zhou, Yu Chen, Yawen Tang, Tianhong Lu
Electrochimica Acta 2010 Volume 55(Issue 16) pp:4789-4798
Publication Date(Web):30 June 2010
DOI:10.1016/j.electacta.2010.03.037
Electrochemical oxidation of dopamine (DA) generally leads to electrode passivation due to accumulation of reaction products. Addition of ethylenediamine-tetramethylene phosphonic acid (EDTMP) to the supporting electrolyte can decrease the formal potential (E0′E0′) of DA oxidation and enhance the antifouling capability of bare Au electrode due to the strong interaction between EDTMP and DA. Subsequently, an EDTMP modified zirconia films electrode is synthesized by using self-assembly method. The electrochemical measurements reveal the modified electrode possesses the excellent antifouling capability for DA oxidation and long-termed stability. In addition, the EDTMP modified zirconia films electrode can be used as a functional interface to sensitively and selectively detect DA in the presence of highly concentrated ascorbic acid (AA) due to the electrostatic interactions between the negatively charged phosphonic acid groups with DA.
Co-reporter:Fan Zhang, Yue Zhou, Yu Chen, Zhongwen Shi, Yawen Tang, Tianhong Lu
Journal of Colloid and Interface Science 2010 Volume 351(Issue 2) pp:421-426
Publication Date(Web):15 November 2010
DOI:10.1016/j.jcis.2010.07.063
In the preparation and storage of gold nanoparticles (Au-NPs) in colloidal form, the stability of the colloid is of utmost importance. We report a novel strategy for the synthesis of the phosphonic acid-functionalized gold nanoparticles (Au-NPs) with the high colloid stability by using ethylenediamine-tetramethylene phosphonic acid (EDTMP) as the reducing agent and its oxidation product as the stabilizing agent. The resultant phosphonic acid-functionalized Au-NPs show a remarkable colloidal stability, which likely arises from strong electrostatic effect of negatively charged phosphonate groups and the extremely hydrophilic property of phosphonate groups. Through the present method, the scope of reducing and stabilizing agents for preparation of phosphonic acid-functionalized Au-NPs extend from the PO3H2-terminated thiols to the aminopolyphosphonates.Graphical abstractThe phosphonic acid-functionalized gold nanoparticles (Au-NPs) with the high colloid stability was synthesized by using ethylenediamine-tetramethylene phosphonic acid as the reducing agent and its oxidation product as the stabilizing agent.Research highlights► The phosphonic acid-functionalized gold nanoparticles possess high colloid stability. ► EDTMP is used as the reducing agent and its oxidation product act as the stabilizing agent. ► The particle size can be controlled by simple adjusting the feeding ratio of EDTMP/Au.
Co-reporter:Yawen Tang, Shuang Cao, Yu Chen, Tianhong Lu, Yiming Zhou, Lude Lu, Jianchun Bao
Applied Surface Science 2010 Volume 256(Issue 13) pp:4196-4200
Publication Date(Web):15 April 2010
DOI:10.1016/j.apsusc.2010.01.124
Abstract
The carbon-supported Pd–Fe catalyst (Pd–Fe/C) is prepared in the H2O/tetrahydrofuran (THF) mixture solvent under the low temperature. The homemade Pd–Fe/C catalyst contains two forms of iron species, alloying and non-alloying Fe. The alloying Fe species is hardly dissolved in 0.5 M H2SO4 solution, while the non-alloying Fe species is easily dissolved in 0.5 M H2SO4 solution. The electrochemical measurements show the electrocatalytic activity of the Pd–Fe/C catalyst with the acid treatment for the oxygen reduction is higher than that of the Pd–Fe/C catalyst without the acid treatment, illustrating that the non-alloying Fe species suppresses the electrocatalytic activity of the Pd–Fe/C catalyst. In contrast, the alloying Fe species promotes the electrocatalytic activity of the Pd–Fe/C catalyst for the oxygen reduction, which is likely attributed to the change of the electron structure of Pd atom and/or bond length of Pd–Pd in the Pd–Fe/C catalyst.
Co-reporter:Yu Chen, Guojie Zhang, Juan Ma, Yiming Zhou, Yawen Tang, Tianhong Lu
International Journal of Hydrogen Energy 2010 Volume 35(Issue 19) pp:10109-10117
Publication Date(Web):October 2010
DOI:10.1016/j.ijhydene.2010.07.170
Single-wall carbon nano-tubes (SWNTs), multi-wall carbon nano-tubes (MWNTs) and Vulcan XC-72 carbon (XC-72) are used as supporting carbon materials to prepare Pt/XC-72, Pt/SWNTs and Pt/MWNTs catalysts in tetrahydrofuran/water/ethanol mixture solution. Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the type of supporting carbon material affects significantly the morphology and the electronic structure of supported Pt nano-particles (NPs). Electrochemical measurements indicate that the Pt/SWNTs catalyst exhibited the highest current density, the lowest onset oxidation potential and the best stability for methanol electro-oxidation among the three samples, indicating SWNTs are an ideal anode catalyst supporting material for the practical application of direct methanol fuel cells.
Co-reporter:Min Zheng, Yu Chen, Yiming Zhou, Yawen Tang, Tianhong Lu
Talanta 2010 Volume 81(Issue 3) pp:1076-1080
Publication Date(Web):15 May 2010
DOI:10.1016/j.talanta.2010.01.063
The surface coverage of 3-mercaptopropylphosphonic acid (HS–CH2CH2CH2–PO3H2, MPPA) self-assembled monolayers (SAMs) on gold surface can be controlled by the dissociation degree of phosphonic acid groups (–PO3H2) in the bulk solution and adsorption time of MPPA molecules under the basic condition. Electrochemical measurements show that the low-density MPPA-SAMs modified gold electrode enhances significantly the kinetics of electron transfer of dopamine (DA), and improves the antifouling capability of modified electrode towards DA oxidation. The present results offer crucial information for design and optimization of the electrochemical sensors for DA determination.
Co-reporter:Pan Li, Hailing Liu, Yu Ding, Yi Wang, Yu Chen, Yiming Zhou, Yawen Tang, Haiyan Wei, Chenxin Cai and Tianhong Lu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 30) pp:NaN15378-15378
Publication Date(Web):2012/06/11
DOI:10.1039/C2JM31350B
A facile noncovalent approach is proposed to graft phosphonate groups onto the surface of single-walled carbon nanotubes (SWNTs) by π–π stacking interactions between naphthalen-1-ylmethylphosphonic acid (NYPA) and SWNTs. Ultraviolet-visible (UV-vis) spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR) spectroscopy and zeta potential analysis confirm the phosphonate groups noncovalently attach on the SWNTs surface, in accordance with the prediction of molecular dynamics (MD) simulations. The phosphonate functionalized SWNTs have good solubility in polar solvent due to the big electrostatic repulsion between phosphonate groups, the strong hydration force of phosphonate groups and the partial debundling of SWNTs. X-ray diffraction (XRD) and Raman spectroscopy measurements demonstrate the water-soluble phosphonate functionalized SWNTs almost completely preserve the electronic and structural integrity of the pristine SWNTs. Meanwhile, the as-prepared phosphonate functionalized SWNTs show good biocompatibility for protein immobilization. Consequently, myoglobin (Mb) proteins immobilized on the phosphonate functionalized SWNTs show excellent bioelectrocatalytic activity towards the reduction of hydrogen peroxide due to the exciting electronic properties of the phosphonate functionalized SWNTs and the fast electron transfer rate of Mb.
Co-reporter:Jiangfeng Xu, Xinyu Liu, Yu Chen, Yiming Zhou, Tianhong Lu and Yawen Tang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 44) pp:NaN23667-23667
Publication Date(Web):2012/10/09
DOI:10.1039/C2JM35649J
Three-dimensional (3D) platinum–cobalt alloy networks nanostructures with a high alloying degree were synthesized through a room temperature wet-chemical synthetic method using the K2PtCl4/K3Co(CN)6 cyanogel as reaction precursor in the absence of surfactants and templates. The size, morphology and surface composition of platinum–cobalt alloy networks nanostructures were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), selected area electron diffraction (SAED), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The 3D backbone structure and double-metallic property of the K2PtCl4/K3Co(CN)6 cyanogel are responsible for the 3D structure and the high alloying degree of the as-prepared products, respectively. Compared to the pure Pt nanoparticles, 3D platinum–cobalt alloy networks nanostructures exhibit superior electrocatalytic activity and stability for the methanol oxidation reaction (MOR), which is ascribed to their unique 3D structure and alloy properties.
Co-reporter:Gengtao Fu, Ke Wu, Xian Jiang, Lin Tao, Yu Chen, Jun Lin, Yiming Zhou, Shaohua Wei, Yawen Tang, Tianhong Lu and Xinghua Xia
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 11) pp:NaN3802-3802
Publication Date(Web):2013/01/10
DOI:10.1039/C3CP44191A
The synthesis of Pt nanocrystals with controlled size and morphology has drawn enormous interest due to their particular catalytic activity. We present a facile and green hydrothermal method for synthesizing monodisperse Pt nanocubes (Pt-NCs) with polyallylamine hydrochloride (PAH) as a complex-forming agent, capping agent and facet-selective agent, and formaldehyde as a reductant. The formation mechanism, particle size and surface composition of the Pt-NCs were investigated by Ultraviolet and visible spectroscopy (UV-vis), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), etc. In the proposed PAH–K2PtCl4–HCHO synthesis system, the raw material could be reutilized to re-synthesize the Pt-NCs, and the particle size of the Pt-NCs could be readily controlled by the reduction rate of the PtII species in the PtII–PAH complex. After UV/Ozone and electrochemical cleaning, the residual PAH on the Pt-NC surfaces still strongly influenced the d-band centre of Pt due to the strong N–Pt interaction. The as-prepared 6 nm Pt-NCs showed superior electrocatalytic activity (mass activity and specific activity) and stability towards the oxygen reduction reaction (ORR) in both H2SO4 and HClO4 electrolytes compared to the commercial E-TEK Pt black, owing to the combination of the facets effect and electronic effect.
Co-reporter:Gengtao Fu, Wei Han, Lifang Yao, Jun Lin, Shaohua Wei, Yu Chen, Yawen Tang, Yiming Zhou, Tianhong Lu and Xinghua Xia
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:NaN17611-17611
Publication Date(Web):2012/07/09
DOI:10.1039/C2JM32381H
We report a facile methodology for one-step synthesis of the porous palladium nanospheres (Pd-NSS) using polyallylamine hydrochloride (PAH) as the complex-forming agent and stabilizing agent under mild reaction conditions (35 °C). The size, integrity, nature and composition of the Pd-NSS are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–adsorption experiments, energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), zeta potential, ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infrared spectroscopy (FT-IR), etc. These spectral studies confirm that the PAH functionalized Pd-NSS are three-dimensionally interconnected porous nanostructures with primary nanoparticles as building blocks. Further experiential investigations show that the particle size of the Pd-NSS can be readily controlled by altering the ratio of PdCl2 to PAH during synthesis, and the Pd-NSS possess high catalytic activity and good stability for the Mizoroki–Heck reaction.
Co-reporter:Jiangfeng Xu, Gengtao Fu, Yawen Tang, Yiming Zhou, Yu Chen and Tianhong Lu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 27) pp:NaN13590-13590
Publication Date(Web):2012/05/16
DOI:10.1039/C2JM32012F
Three-dimensional platinum nanochain network (Pt-3NCNW) nanostructures are synthesized through a thermal decomposition method using platinum(IV)-complexes as reaction precursors in the absence of surfactants and templates. The size, morphology and surface composition of Pt-3NCNWs are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). These spectral studies confirm the as-papered products are three-dimensionally interconnected network nanostructures with primary Pt nanochains as building blocks, and the Pt nanochains grow from the primary spheric Pt nanoparticles via oriented attachment. Compared to the commercial Pt black catalyst, the Pt-3NCNW nanostructures exhibit superior electrocatalytic activity and stability towards oxygen reduction reactions, which is ascribed to their unique properties such as the few surface defect sites and the low hydroxyl surface coverage on one-dimensional Pt nanochains, as well as fast O2 diffusion in three-dimensional structures.
Co-reporter:Gengtao Fu ; Ke Wu ; Jun Lin ; Yawen Tang ; Yu Chen ; Yiming Zhou ;Tianhong Lu
The Journal of Physical Chemistry C () pp:
Publication Date(Web):April 13, 2013
DOI:10.1021/jp400502y
Well-defined and strikingly monomorphic Pt–Pd alloy nanoflowers (Pt–Pd ANFs) with dominant {111} facets were successfully synthesized through a facile cochemical reduction method in a poly(allylamine hydrochloride) (PAH) based aqueous solution. The detailed morphology, composition, and structure of the Pt–Pd ANFs were investigated by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy dispersive spectrum (EDS), nitrogen adsorption–desorption isotherms (SADI), EDS mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), demonstrating the Pt–Pd ANFs were highly porous and a self-supported structure. The formation mechanism of the Pt–Pd ANFs were investigated by TEM and Fourier transform infrared (FT-IR), indicating that the existence of PAH and rapid growth of crystal nuclei were essential for the formation of the Pt–Pd ANFs. The electrocatalytic activity and stability of the Pt–Pd ANFs for the oxygen reduction reaction (ORR) were investigated by rotating disk electrode voltammetry in 0.1 M HClO4 solution. The electrochemical tests indicated the {111}-enclosed Pt–Pd ANFs exhibited superior ORR activity along with satisfactory stability and methanol-tolerant ability under acidic conditions, which made them promising electrocatalysts for the future.
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