Co-reporter:Rong Chen, Cangjie Yang, Weizheng Cai, Hsin-Yi Wang, Jianwei Miao, Liping Zhang, Shengli Chen, and Bin Liu
ACS Energy Letters May 12, 2017 Volume 2(Issue 5) pp:1070-1070
Publication Date(Web):April 18, 2017
DOI:10.1021/acsenergylett.7b00219
Co-reporter:Laiquan Li, Hongbin Yang, Jianwei Miao, Liping Zhang, Hsin-Yi Wang, Zhiping Zeng, Wei HuangXiaochen Dong, Bin Liu
ACS Energy Letters - New in 2016 2017 Volume 2(Issue 2) pp:
Publication Date(Web):January 5, 2017
DOI:10.1021/acsenergylett.6b00681
Carbon-based nanomaterials have been widely studied as promising electrocatalysts for energy conversion and storage. Understanding the oxygen evolution and reduction reactions on carbon-based nanomaterials is of critical importance for development of highly active metal-free electrocatalysts. Here, the adsorption of oxygenated intermediates during oxygen evolution reaction (OER) on carbon nanotubes (CNTs) was examined by ex-situ X-ray photoelectron spectroscopy and in situ electrochemical impedance spectroscopy. The results demonstrate that the carbon atoms on CNTs near the C═O functional groups are active for OER. On the basis of this result, we further revealed the origin of the enhanced intermediate adsorption on surface-oxidized CNTs and the relationship between surface groups and apparent activation energy. Our study gained new understanding of OER on oxygen-doped carbon nanomaterials and provided an effective approach for investigating electrocatalysis on heteroatom-doped carbon electrocatalysts.
Co-reporter:Junyu Zhang;Guangcan Xiao;Fang-Xing Xiao
Materials Chemistry Frontiers 2017 vol. 1(Issue 2) pp:231-250
Publication Date(Web):2017/02/16
DOI:10.1039/C6QM00141F
One-dimensional (1D) TiO2 nanostructures have been regarded as ideal candidates for solar energy conversion due to their unique structural merits including large surface-to-volume ratio, fast and long-distance charge transport, and good physi-co-chemical stability. Over the past few decades, tremendous interest has been devoted to fabricating a large number of 1D TiO2 based heterostructures for extensive photocatalytic applications. In this review article, we provide a comprehensive and systematic discussion on the latest developments of a large variety of 1D TiO2 based composite heterostructures along with their versatile photocatalytic applications in various research fields including nonselective photodegradation of organic pollutants for environmental remediation, photocatalytic selective organic transformation, as well as solar energy conversion for fuel production. Furthermore, future challenges and promising perspectives for this increasingly booming photocatalytic technology are also presented. It is anticipated that this review article will provide enriched and useful information on rational utilization of the outstanding structure and electronic properties of 1D TiO2 nanostructures for a wide range of photocatalytic applications.
Co-reporter:Fang-Xing Xiao
Nanoscale (2009-Present) 2017 vol. 9(Issue 43) pp:17118-17132
Publication Date(Web):2017/11/09
DOI:10.1039/C7NR06697J
Although recent years have witnessed considerable progress in the synthesis of metal clusters, there is still a paucity of reports on photoelectrochemical (PEC) properties of metal cluster/semiconductor systems for solar energy conversion. In this work, highly ordered glutathione (GSH)-protected gold (Au) cluster (Aux@GSH) enwrapped ZnO nanowire array (NW) heterostructures (Aux/ZnO NWs) were designed by a facile, green, simple yet efficient in situ etching-induced electrostatic self-assembly strategy by modulating the intrinsic surface charge properties of building blocks, which renders negatively charged Aux clusters spontaneously and uniformly self-assembles them on positively charged ZnO NWs framework with intimate interfacial integration. It was unraveled that such Aux/ZnO NWs heterostructures demonstrated significantly enhanced PEC water splitting performance in comparison with single ZnO NWs, Au nanoparticles (Au/ZnO NWs) and GSH-capped Agx clusters (Agx/ZnO NWs) decorated ZnO NWs counterparts under both simulated solar and visible light irradiation. The vitally important role of Aux clusters as photosensitizer was unambiguously revealed and the merits of Aux clusters in boosting charge transfer arising from their unique core–shell architecture were highlighted by systematic comparison under identical conditions, based on which Aux cluster-mediated PEC water splitting mechanism is delineated. It is anticipated that our work can highlight the possibility of harnessing metal clusters as efficient light-harvest antennas and open new avenues for rational construction of various highly energy efficient metal cluster/semiconductor heterostructures for widespread photocatalytic and PEC applications.
Co-reporter:Fanan Wang, Yuanmiao Sun, Yanghua He, Linghui Liu, Jinming Xu, Xiaochen Zhao, Guangzhao Yin, Liping Zhang, Shuzhou Li, Qing Mao, Yanqiang Huang, Tao Zhang, Bin Liu
Nano Energy 2017 Volume 37(Volume 37) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.nanoen.2017.04.050
•A carbothermal ammonia reduction strategy for one-pot preparation of transition-metal-based hydrogen evolution reaction electrocatalyst.•Simultaneous incorporation of C and N atoms as well as cooperation of bimetals (Ni and Mo) to tune the bonding strength of M-H.•Highly active electrocatalyst for HER in alkaline medium.•Long time chemical and physical stability under corrosive environment with severe mechanical disturbance.We report a carbothermal ammonia reduction (CAR) strategy for one-pot preparation of highly efficient and durable hydrogen evolution reaction (HER) electrocatalyst composed of earth abundant early transition metals. In this strategy, resin is applied both as the pre-binder and carbon source, and Pluronic F127 as the structure-directing agent. Upon annealing in NH3, the Mo-containing precursor on Ni foam undergoes the CAR, and simultaneously Ni from the substrate diffuses out, resulting in the formation of a quaternary complex structure of molybdenum-nickel bimetallic carbonitride (MoNiNC). The as-prepared electrode showed outstanding HER performance with an overpotential of 150 mV at 50 mA cm−2 and maintained steady hydrogen bubble evolution for continuous 48 h. Our strategy offers a quick and simple way to fabricate earth-abundant HER electrode with highly efficient and durable electrocatalytic performance.Download high-res image (281KB)Download full-size image
Co-reporter:Zhijian Wang;Junmei Wang;Li Li;Jianfeng Zheng;Suping Jia;Jiazang Chen;Zhenping Zhu
Journal of Materials Chemistry A 2017 vol. 5(Issue 38) pp:20131-20135
Publication Date(Web):2017/10/03
DOI:10.1039/C7TA06085H
Water oxidation and reduction over semiconductor-based photocatalysts intrinsically occur at different spatial sites. Modulation of the reaction sites and charge transfer between them are logically important in speeding up the reaction. Here, we demonstrate that divorcing a CdSe–CdS–Pt donor–acceptor system on different surface sites of TiO2 can significantly increase the H2 generation rate. The increase is derived from an effective reset of water oxidation and reduction sites. Widening of the site distance by employing a TiO2 membraniform acceptor effectively decreases the electron–hole recombination especially for a membrane of TiO2 nanotube arrays. The oriented charge transfer characteristic of TiO2 nanotube arrays benefits long-range electron transport, thereby increasing the electron lifetime and reaction rate. When more conductive carbon nanotube arrays serve as an electron acceptor to replace TiO2, the electron transport is greatly improved, resulting in an ultrahigh H2 generation rate of 1270 mmol g−1 h−1. This work provides a basis for the design and construction of highly efficient photocatalysts through rational modulation of reaction sites and charge transport.
Co-reporter:Pei-Yang Gu;Zilong Wang;Fang-Xing Xiao;Zongqiong Lin;Rongbin Song;Qing-Feng Xu;Jian-Mei Lu;Qichun Zhang
Materials Chemistry Frontiers 2017 vol. 1(Issue 3) pp:495-498
Publication Date(Web):2017/03/09
DOI:10.1039/C6QM00113K
Present photoelectrochemical (PEC) cells for water splitting are based on inorganic electrodes. For future large-scale applications, electrodes that are metal-free, of low cost, and with sustainable availability are crucial. Herein, we report a new ambipolar larger azaacene (DQNDN) as a single-active-element-based photocathode in PEC cells with a current density of 0.13 mA cm−2 at −0.13 V versus RHE.
Co-reporter:Jiajian Gao;Chunmiao Jia
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 23) pp:5602-5607
Publication Date(Web):2017/11/27
DOI:10.1039/C7CY01549F
Reduction of CO2 by H2 produced from renewable electricity on a large scale would benefit both carbon recycling as well as H2 storage and transport. Among the various CO2 hydrogenation reaction products, light olefins, such as ethylene and propylene, are very important intermediates in the chemical industry. However, very efficient catalytic systems that are able to drive CO2 hydrogenation reactions selectively to make olefins do not exist although the reactions are thermodynamically favorable. In this study, we demonstrated a selective hydrogenation process to directly convert CO2 to light olefins via a bifunctional catalyst composed of a methanol synthesis (In2O3/ZrO2) catalyst and a methanol-to-olefins (SAPO-34) catalyst. Under typical reaction conditions (e.g., 15 bar, 400 °C, and a space velocity of 12 L gcat−1 h−1), light olefins (ethylene and propylene) with a selectivity of 80–90% in hydrocarbons can be obtained with a CO2 conversion of ∼20%. To the best of our knowledge, this is the highest selectivity reported to date, which significantly surpasses the value obtained over conventional iron or cobalt CO2 Fischer–Tropsch synthesis catalysts (typically less than 50%). Moreover, our designed bifunctional catalyst shows good catalytic stability and can run for 50 h continuously without obvious activity decay. Our study provides an important contribution for CO2 conversion to value-added chemicals.
Co-reporter:Fang-Xing Xiao, Mario Pagliaro, Yi-Jun Xu and Bin Liu
Chemical Society Reviews 2016 vol. 45(Issue 11) pp:3088-3121
Publication Date(Web):22 Mar 2016
DOI:10.1039/C5CS00781J
Over the past few decades, layer-by-layer (LbL) assembly of multilayer thin films has garnered considerable interest on account of its ability to modulate nanometer control over film thickness and its extensive choice of usable materials for coating planar and particulate substrates, thus allowing for the fabrication of responsive and functional thin films for their potential applications in a myriad of fields. Herein, we provide elaborate information on the current developments of LbL assembly techniques including different properties, molecular interactions, and assembly methods associated with this promising bottom-up strategy. In particular, we highlight the principle for rational design and fabrication of a large variety of multilayer thin film systems including multi-dimensional capsules or spatially hierarchical nanostructures based on the LbL assembly technique. Moreover, we discuss how to judiciously choose the building block pairs when exerting the LbL assembly buildup which enables the engineering of multilayer thin films with tailor-made physicochemical properties. Furthermore, versatile applications of the diverse LbL-assembled nanomaterials are itemized and elucidated in light of specific technological fields. Finally, we provide a brief perspective and potential future challenges of the LbL assembly technology. It is anticipated that our current review could provide a wealth of guided information on the LbL assembly technique and furnish firm grounds for rational design of LbL assembled multilayer assemblies toward tangible applications.
Co-reporter:Sung-Fu Hung;Fang-Xing Xiao;Ying-Ya Hsu;Nian-Tzu Suen;Hong-Bin Yang;Hao Ming Chen
Advanced Energy Materials 2016 Volume 6( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/aenm.201501339
Plasmonic nanostructures are capable of driving photocatalysis through absorbing photons in the visible region of the solar spectrum. Unfortunately, the short lifetime of plasmon-induced hot carriers and sluggish surface chemical reactions significantly limit their photocatalytic efficiencies. Moreover, the thermodynamically favored excitation mechanism of plasmonic photocatalytic reactions is unclear. The mechanism of how the plasmonic catalyst could enhance the performance of chemical reaction and the limitation of localized surface plasmon resonance devices is proposed. In addition, a design is demonstrated through co-catalyst decorated plasmonic nanoparticles Au/IrOX upon a semiconductor nanowire-array TiO2 electrode that are able to considerably improve the lifetime of plasmon-induced charge-carriers and further facilitate the kinetics of chemical reaction. A thermodynamically favored excitation with improved kinetics of hot carriers is revealed through electrochemical studies and characterization of X-ray absorption spectrum. This discovery provides an opportunity to efficiently manage hot carriers that are generated from metal nanostructures through surface plasmon effects for photocatalysis applications.
Co-reporter:Jiazang Chen; Liping Zhang; Zhenhui Lam; Hua Bing Tao; Zhiping Zeng; Hong Bin Yang; Jianqiang Luo; Lin Ma; Bo Li; Jianfeng Zheng; Suping Jia; Zhijian Wang; Zhenping Zhu
Journal of the American Chemical Society 2016 Volume 138(Issue 9) pp:3183-3189
Publication Date(Web):February 11, 2016
DOI:10.1021/jacs.5b13464
Due to the limited electronic conductivity, the application of many metal oxides that may have attractive (photo)-electrochemical properties has been limited. Regarding these issues, incorporating low-dimensional conducting scaffolds into the electrodes or supporting the metal oxides onto the conducting networks are common approaches. However, some key electronic processes like interfacial charge transfer are far from being consciously concerned. Here we use a carbon-TiO2 contact as a model system to demonstrate the electronic processes occurring at the metal–semiconductor interface. To minimize the energy dissipation for fast transfer of electrons from semiconductor to carbon scaffolds, facilitating electron tunneling while avoiding high energy-consuming thermionic emission is desired, according to our theoretical simulation of the voltammetric behaviors. To validate this, we manage to sandwich ultrathin TiO2 interlayers with heavy electronic doping between the carbon conductors and dopant-free TiO2. The radially graded distribution of the electronic doping along the cross-sectional direction of carbon conductor realized by immobilizing the dopant species on the carbon surface can minimize the energy consumption for contacts to both the carbon and the dopant-free TiO2. Our strategy provides an important requirement for metal oxide electrode design.
Co-reporter:Hua Bing Tao, Liwen Fang, Jiazang Chen, Hong Bin Yang, Jiajian Gao, Jianwei Miao, Shengli Chen, and Bin Liu
Journal of the American Chemical Society 2016 Volume 138(Issue 31) pp:9978-9985
Publication Date(Web):July 21, 2016
DOI:10.1021/jacs.6b05398
A number of important reactions such as the oxygen evolution reaction (OER) are catalyzed by transition metal oxides (TMOs), the surface reactivity of which is rather elusive. Therefore, rationally tailoring adsorption energy of intermediates on TMOs to achieve desirable catalytic performance still remains a great challenge. Here we show the identification of a general and tunable surface structure, coordinatively unsaturated metal cation (MCUS), as a good surface reactivity descriptor for TMOs in OER. Surface reactivity of a given TMO increases monotonically with the density of MCUS, and thus the increase in MCUS improves the catalytic activity for weak-binding TMOs but impairs that for strong-binding ones. The electronic origin of the surface reactivity can be well explained by a new model proposed in this work, wherein the energy of the highest-occupied d-states relative to the Fermi level determines the intermediates’ bonding strength by affecting the filling of the antibonding states. Our model for the first time well describes the reactivity trends among TMOs, and would initiate viable design principles for, but not limited to, OER catalysts.
Co-reporter:Jiazang Chen;Hong Bin Yang;Hua Bing Tao;Liping Zhang;Jianwei Miao;Hsin-Yi Wang;Junze Chen;Hua Zhang
Advanced Functional Materials 2016 Volume 26( Issue 3) pp:456-465
Publication Date(Web):
DOI:10.1002/adfm.201504105
In a photoelectrochemical cell, the most concerned issue in the nanostructured TiO2 electrode is the charge transport, which consists of the internal movement of electrons in TiO2 nanostructures and the intergrain charge transfer. Here, inspired by electrochemical studies on different polymorphs of TiO2, it is proposed to bridge the adjacent building blocks and fence the electron transport highways in TiO2 electrodes by surface rutilization of anatase nanorods. The ultrathin rutilized layer completely coated on the anatase surface has a slightly higher conduction band edge than that of anatase. The obtained surface rutilized anatase nanorods can not only improve the intergrain charge transfer while maintaining fast electron transport within anatase but also minimize the internal energy consumption and protect the electrons in TiO2 electrodes from recombination, which are beneficial to the charge collection and can significantly improve the photovoltaic performance of photoelectrochemical cells.
Co-reporter:Fang He, Gang Chen, Yansong Zhou, Yaoguang Yu, Laiquan Li, Sue Hao and Bin Liu
Journal of Materials Chemistry A 2016 vol. 4(Issue 10) pp:3822-3827
Publication Date(Web):03 Feb 2016
DOI:10.1039/C6TA00497K
A ZIF-8 derived carbon (C-ZIF)/g-C3N4 composite was constructed for the first time through facile thermal condensation of a zeolitic imidazolate framework (ZIF-8) and melamine. The obtained C-ZIF/g-C3N4 composite exhibited an obviously enhanced photocatalytic H2 production rate compared to pure g-C3N4 under visible light irradiation. The 1 wt% C-ZIF/g-C3N4 composite without loading the Pt co-catalyst showed 36.2 times higher H2 evolution rate than that of pure g-C3N4, which is even 2.8 times higher than that of Pt/g-C3N4 (the state-of-the-art g-C3N4-based photocatalyst). It was revealed by photoluminescence spectroscopy, time-resolved fluorescence spectroscopy and electrochemical impedance spectroscopy that the formed C-ZIF and g-C3N4 junction could promote quick charge carrier separation and transfer. The C-ZIF not only acted as an effective electron acceptor, but also functioned as an efficient hydrogen evolution reaction (HER) cocatalyst to promote photocatalytic hydrogen evolution. Our work provides an effective way for the development of metal-free, all carbon-based photocatalysts for H2 evolution.
Co-reporter:Hsin-Yi Wang, Jiazang Chen, Fang-Xing Xiao, Jianwei Zheng and Bin Liu
Journal of Materials Chemistry A 2016 vol. 4(Issue 18) pp:6926-6932
Publication Date(Web):30 Oct 2015
DOI:10.1039/C5TA08202A
Semiconductor nanostructures with specially exposed reactive crystal facets are promising to promote photocatalytic/photoelectrochemical reactions. Here, we demonstrate that the introduction of niobium into TiO2 can modify TiO2 surface chemistry, which in turn influences the growth of TiO2 nanostructures from one-dimensional rutile nanorods at a low niobium doping concentration to two-dimensional anatase nanosheets at a high niobium doping concentration. Additionally, the electronic structure, optical properties, and surface activity for O2 adsorption are substantially influenced for Nb-doped TiO2 by electron donation from the niobium dopant, which significantly enhances the light-induced generation of super oxide radicals (O2−˙), and thus improves the photocatalytic activity of Nb-doped TiO2.
Co-reporter:Hsin-Yi Wang, Han-Yi Chen, Ying-Ya Hsu, Ulrich Stimming, Hao Ming Chen, and Bin Liu
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 42) pp:29186
Publication Date(Web):October 11, 2016
DOI:10.1021/acsami.6b11185
We report that an ultrafast kinetics of reversible metal-ion insertion can be realized in anatase titanium dioxide (TiO2). Niobium ions (Nb5+) were carefully chosen to dope and drive anatase TiO2 into very thin nanosheets standing perpendicularly onto transparent conductive electrode (TCE) and simultaneously construct TiO2 with an ion-conducting surface together with expanded ion diffusion channels, which enabled ultrafast metal ions to diffuse across the electrolyte/solid interface and into the bulk of TiO2. To demonstrate the superior metal-ion insertion rate, the electrochromic features induced by ion intercalation were examined, which exhibited the best color switching speed of 4.82 s for coloration and 0.91 s for bleaching among all reported nanosized TiO2 devices. When performed as the anode for the secondary battery, the modified TiO2 was capable to deliver a highly reversible capacity of 61.2 mAh/g at an ultrahigh specific current rate of 60 C (10.2 A/g). This fast metal-ion insertion behavior was systematically investigated by the well-controlled electrochemical approaches, which quantitatively revealed both the enhanced surface kinetics and bulk ion diffusion rate. Our study could provide a facile methodology to modulate the ion diffusion kinetics for metal oxides.Keywords: doping modulation; lattice expansion; metal-ion diffusion; surface kinetics; TiO2 nanosheets
Co-reporter:Liping Zhang;Ping Cui;Hongbin Yang;Jiazang Chen;Fangxing Xiao;Yuanyuan Guo;Ye Liu;Weina Zhang;Fengwei Huo
Advanced Science 2016 Volume 3( Issue 1) pp:
Publication Date(Web):
DOI:10.1002/advs.201500243
Co-reporter:Fang He, Gang Chen, Jianwei Miao, Zhenxing Wang, Dongmeng Su, Song Liu, Weizheng Cai, Liping Zhang, Sue Hao, and Bin Liu
ACS Energy Letters 2016 Volume 1(Issue 5) pp:969
Publication Date(Web):October 12, 2016
DOI:10.1021/acsenergylett.6b00398
Hollow one-dimensional (1-D) nanostructures have drawn great attention in heterogeneous photocatalysis. Herein, we report that tapered polyacrylonitrile-derived carbon (C-PAN)/g-C3N4 composite nanotubes can be synthesized through a facile sulfur-mediated self-templating method via thermal condensation of polyacrylonitrile (PAN), melamine, and sulfur. The hollow tapered C-PAN/g-C3N4 composite nanotubes exhibit superior photocatalytic H2 evolution performance under visible light irradiation. The 5 wt % C-PAN/g-C3N4 composite nanotubes show a 16.7 times higher photocatalytic H2 evolution rate than that of pure g-C3N4, which is even 4.7 times higher than that of a 5 wt % C-PAN/g-C3N4 nanosheet composite obtained without sulfur. The hollow nanotubular composite structure provides g-C3N4 with higher specific surface area, enhanced light absorption, and better charge carrier separation and transfer, which synergistically contribute to the superior photocatalytic activity. Our work provides a new strategy to develop carbon-based architected photocatalysts.
Co-reporter:Liping Zhang;Rong Chen;Jianqiang Luo;Jianwei Miao;Jiajian Gao
Nano Research 2016 Volume 9( Issue 11) pp:3388-3393
Publication Date(Web):2016 November
DOI:10.1007/s12274-016-1216-5
Hydrogen production from steam or autothermal alcohol reforming has been widely studied, but these methods require high temperatures and emit CO2. Here, we present a new strategy for the simultaneous room-temperature production of hydrogen and other chemicals without the emission of CO2, via the photoelectrochemical reforming of biomass-derived alcohols. The measured hydrogen quantum efficiencies reach around 80% across the entire visible solar spectrum from 450 to 850 nm, achieving an ultrahigh hydrogen production rate of 7.91 μmol/(min·cm2) under AM 1.5G illumination.
Co-reporter:Rong Chen, Gengzhi Sun, Cangjie Yang, Liping Zhang, Jianwei Miao, Huabing Tao, Hongbin Yang, Jiazang Chen, Peng Chen and Bin Liu
Nanoscale Horizons 2016 vol. 1(Issue 2) pp:156-160
Publication Date(Web):02 Dec 2015
DOI:10.1039/C5NH00082C
A facile and scalable co-precipitation method is developed to prepare stable colloidal NiFe-LDH nanoparticles at room temperature. We further scrolled NiFe-LDH nanoparticles into well-aligned multi-walled carbon nanotube (MWCNT) sheets to form binder-free hybrid microfiber electrodes, which showed excellent OER activity, reaching 180 mA cm−2 at a small overpotential of 255 mV with outstanding durability.
Co-reporter:Zilong Wang;Jianwei Miao;Dr. Guankui Long;Dr. Peiyang Gu;Dr. Junbo Li;Dr. Naoki Aratani;Dr. Hiroko Yamada;Dr. Bin Liu;Dr. Qichun Zhang
Chemistry – An Asian Journal 2016 Volume 11( Issue 4) pp:482-485
Publication Date(Web):
DOI:10.1002/asia.201501276
Abstract
The preparation of large azaacenes is very important because of their great potential in organic electronics. In this report, we successfully synthesized and fully characterized two stable pyrene-fused large azaacenes: octaazadecacene and tetraazaoctacene through employing a relatively moderate aromatic unit pyrene as imbedded species in the backbone of azaacenes to ensure large conjugation and stability. The photoelectrochemical (PEC) studies indicate that both azaacenes display n-type semiconductor behavior.
Co-reporter:Hsin-Yi Wang;Dr. Hongbin Yang;Liping Zhang;Dr. Jiazang Chen ;Dr. Bin Liu
ChemNanoMat 2016 Volume 2( Issue 7) pp:660-664
Publication Date(Web):
DOI:10.1002/cnma.201600035
Abstract
The charge-transport behavior of nanostructured titanium dioxide (TiO2) is of great interest because of the wide range of applications. In this work, we demonstrate a facile approach to improve electron transport in TiO2 nanorods (NRs) by introducing niobium (Nb) dopant into the lattice of TiO2. The TiO2-NRs doped with Nb were grown directly on fluorine doped tin oxide (FTO) substrates by a facile hydrothermal method and used directly as the photoanodes for water oxidation. The TiO2 nanorod electrode doped with 0.25 % of Nb showed 65 % improvement in photocurrent as compared with the pristine TiO2 nanorod electrode. Furthermore, by simply changing the light illuminating direction, the improvement of charge transport induced by Nb doping could be easily identified.
Co-reporter:Hsin-Yi Wang, Sung-Fu Hung, Ying-Ya Hsu, Lulu Zhang, Jianwei Miao, Ting-Shan Chan, Qihua Xiong, and Bin Liu
The Journal of Physical Chemistry Letters 2016 Volume 7(Issue 23) pp:4847-4853
Publication Date(Web):November 13, 2016
DOI:10.1021/acs.jpclett.6b02147
The formation of μ-OO peroxide (Co–OO–Co) moieties on spinel Co3O4 electrocatalyst prior to the rise of the electrochemical oxygen evolution reaction (OER) current was identified by in situ spectroscopic methods. Through a combination of independent in situ X-ray absorption, grazing-angle X-ray diffraction, and Raman analysis, we observed a clear coincidence between the formation of μ-OO peroxide moieties and the rise of the anodic peak during OER. This finding implies that a chemical reaction step could be generally ignored before the onset of OER current. More importantly, the tetrahedral Co2+ ions in the spinel Co3O4 could be the vital species to initiate the formation of the μ-OO peroxide moieties.
Co-reporter:Hong Bin Yang;Jianwei Miao;Sung-Fu Hung;Jiazang Chen;Liping Zhang;Xizu Wang;Hua Bing Tao;Rong Chen;Hao Ming Chen;Jiajian Gao;Liming Dai
Science Advances 2016 Volume 2(Issue 4) pp:e1501122
Publication Date(Web):22 Apr 2016
DOI:10.1126/sciadv.1501122
Doping of graphene with nitrogen imparted bifunctional electrocatalytic activities for efficient energy conversion and storage.
Co-reporter:Yibo Yan, Jianwei Miao, Zhihong Yang, Fang-Xing Xiao, Hong Bin Yang, Bin Liu and Yanhui Yang
Chemical Society Reviews 2015 vol. 44(Issue 10) pp:3295-3346
Publication Date(Web):09 Apr 2015
DOI:10.1039/C4CS00492B
Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.
Co-reporter:Hsin-Yi Wang;Ying-Ya Hsu;Rong Chen;Ting-Shan Chan;Hao Ming Chen
Advanced Energy Materials 2015 Volume 5( Issue 10) pp:
Publication Date(Web):
DOI:10.1002/aenm.201500091
Efficient and earth abundant electrocatalysts for high-performance oxygen evolution reaction (OER) are essential for the development of sustainable energy conversion technologies. Here, a new hierarchical Ni–Co oxide nanostructure, composed of small secondary nanosheets grown on primary nanosheet arrays, is synthesized via a topotactic transformation of Ni–Co layered double hydroxide. The Ni3+-rich surface benefits the formation of NiOOH, which is the main redox site as revealed via in situ X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopy. The Ni–Co oxide hierarchical nanosheets (NCO–HNSs) deliver a stable current density of 10 mA cm−2 at an overpotential of ≈0.34 V for OER with a Tafel slope of as low as 51 mV dec−1 in alkaline media. The improvement in the OER activity can be ascribed to the synergy of large surface area offered by the 3D hierarchical nanostructure and the facile formation of NiOOH as the main active sites on the surface of NCO–HNSs to decrease the overpotential and facilitate the catalytic reaction.
Co-reporter:Hsin-Yi Wang; Sung-Fu Hung; Han-Yi Chen; Ting-Shan Chan; Hao Ming Chen
Journal of the American Chemical Society 2015 Volume 138(Issue 1) pp:36-39
Publication Date(Web):December 28, 2015
DOI:10.1021/jacs.5b10525
Spinel Co3O4, comprising two types of cobalt ions: one Co2+ in the tetrahedral site (Co2+Td) and the other two Co3+ in the octahedral site (Co3+Oh), has been widely explored as a promising oxygen evolution reaction (OER) catalyst for water electrolysis. However, the roles of two geometrical cobalt ions toward the OER have remained elusive. Here, we investigated the geometrical-site-dependent OER activity of Co3O4 catalyst by substituting Co2+Td and Co3+Oh with inactive Zn2+ and Al3+, respectively. Following a thorough in operando analysis by electrochemical impedance spectroscopy and X-ray absorption spectroscopy, it was revealed that Co2+Td site is responsible for the formation of cobalt oxyhydroxide (CoOOH), which acted as the active site for water oxidation.
Co-reporter:Fang-Xing Xiao; Zhiping Zeng
Journal of the American Chemical Society 2015 Volume 137(Issue 33) pp:10735-10744
Publication Date(Web):August 10, 2015
DOI:10.1021/jacs.5b06323
In recent years, enormous attention has been paid to the construction of metal cluster-semiconductor nanocomposites because of the fascinating and unique properties of metal clusters; however, investigations on photoelectrochemical (PEC) and photocatalytic properties of metal cluster-semiconductor systems are still rare. Moreover, to date, intrinsic correlation between metal clusters and bulk metal nanocrystals has yet to be elucidated. In this work, a facile layer-by-layer (LbL) self-assembly strategy has been developed to judiciously and intimately integrate gold nanocrystals (Au) within the interface between gold clusters (Aux) and hierarchically ordered TiO2 nanotube arrays framework, by which imperative roles of Au nanocrystals as electron relay mediator and plasmonic sensitizer for Aux clusters were revealed. In addition, it was found that synergistic interaction between Au nanocrystals and Aux clusters contributed to promising visible-light-driven photocatalytical and PEC performances. It is anticipated that our work could provide a general way for rationally constructing metal and metal clusters codecorated semiconductor heterostructures and, more significantly, bridge the gap between metal clusters and metal nanocrystals for a diverse range of applications.
Co-reporter:Junbo Li, Jianwei Miao, Guankui Long, Jing Zhang, Yongxin Li, Rakesh Ganguly, Yang Zhao, Yi Liu, Bin Liu and Qichun Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 38) pp:9877-9884
Publication Date(Web):27 Aug 2015
DOI:10.1039/C5TC02010G
N-heteroquinones with both quinone and pyrazine as electron-withdrawing moieties can be potential candidates for n-type organic semiconductor materials. Here, two novel soluble N-heteroquinones: 5,9,14,18-tetra-((triisopropylsilyl)ethynyl)-6,8,15,17-tetraazaheptacene-7,16-dione (TAHD) and 6,10,17,21-tetra-((triisopropylsilyl)ethynyl)-7,9,18,20-tetraazanonacene-8,19-dione (TAND) with different lengths have been synthesized and their structures were fully characterized by 1H NMR, 13C NMR, HRMS and single crystal analysis. Our studies showed that the shorter TAHD molecules are planar in the solid state without intermolecular π–π stacking and the main force to stabilize the packing is the C–H–π interaction between (triisopropylsilyl)ethynyl (TIPS) groups and the backbones. Differently, the larger TAND molecules show slightly twisted structures with the anthracene units bent down and up on the two sites and the dihedral angle between the quinone unit and the anthracene unit is 6.7°. Meanwhile, TAND molecules adopt face-to-face two-dimensional (2D) brickwork arrangement, and the distances between π planes are 3.63 and 3.38 nm, respectively, suggesting the existence of π–π interactions. The visible-light-driven photoelectrochemical behaviors showed that both TAHD and TAND are n-type semiconductors. However, TAHD shows unstable photovoltage response and lower photocurrent due to the absence of π–π interaction while TAND shows stable photovoltage response and a relatively high photocurrent. Our results suggested that the length of the linear N-heteroquinones has large effects on their physical properties, crystal packing and photoelectrochemical behaviors.
Co-reporter:Hsin-Yi Wang, Jiazang Chen, Sunny Hy, Linghui Yu, Zhichuan Xu and Bin Liu
Nanoscale 2015 vol. 7(Issue 48) pp:20777-20777
Publication Date(Web):19 Nov 2015
DOI:10.1039/C5NR90200B
Correction for ‘High-surface-area mesoporous TiO2 microspheres via one-step nanoparticle self-assembly for enhanced lithium-ion storage’ by Hsin-Yi Wang et al., Nanoscale, 2014, 6, 14926–14931.
Co-reporter:Fang-Xing Xiao, Zhiping Zeng, Shao-Hui Hsu, Sung-Fu Hung, Hao Ming Chen, and Bin Liu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 51) pp:28105
Publication Date(Web):December 16, 2015
DOI:10.1021/acsami.5b09091
In situ transformation of glutathione-capped gold (Aux) clusters to gold (Au) nanocrystals under simulated solar light irradiation was achieved and utilized as a facile synthetic approach to rationally fabricate Aux/Au/TiO2 ternary and Au/TiO2 binary heterostructures. Synergistic interaction of Aux clusters and Au nanocrystals contributes to enhanced visible-light-driven photocatalysis.Keywords: metal clusters; metal nanocrystals; photocatalysis; TiO2 nanotube arrays; transformation
Co-reporter:Junkuo Gao, Jianwei Miao, Yongxin Li, Rakesh Ganguly, Yang Zhao, Ovadia Lev, Bin Liu and Qichun Zhang
Dalton Transactions 2015 vol. 44(Issue 32) pp:14354-14358
Publication Date(Web):2015/07/07
DOI:10.1039/C5DT01769F
A simple and facile one-step method for the synthesis of an organic dye-functionalized polyoxometalate (POM) hybrid with visible-light photo-response was reported. The POM hybrid was fully characterized via single crystal XRD, powder XRD, FTIR and elemental analysis. The reaction of the organic dye with inorganic salts gave the dye-functionalized POM (MoBB3), in which the POM cluster was formed in situ. The electronic absorption peak of this hybrid was successfully extended beyond 680 nm. Photoelectrochemical measurement indicated that MoBB3 was photoresponsive under visible-light illumination, suggesting that it is an n-type (electron conductive) semiconducting material. This result might offer a method for the design of novel organic dye-functionalized POMs for photoelectric applications.
Co-reporter:Junyu Zhang, Fang-Xing Xiao, Guangcan Xiao and Bin Liu
New Journal of Chemistry 2015 vol. 39(Issue 1) pp:279-286
Publication Date(Web):03 Oct 2014
DOI:10.1039/C4NJ01346H
In recent years increasing efforts have been devoted to synthesizing hybrid semiconductor nanocomposites; however, it still poses a challenge to fabricate well-defined semiconductor based heterostructures. In this work, a well-defined TiO2 nanobelt functionalized with a CdS quantum dot (viz. TiO2 NB–CdS QD) binary nanostructure has been fabricated by an efficient self-assembly approach based on a facile surface charge tuning. A collection of techniques including X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM), transmission scanning electron microscopy (TEM), and X-ray photoelectron spectra (XPS) was utilized to characterize the structure of TiO2 NB–CdS QD binary heterostructure. It was found that the as-constructed TiO2 NB–CdS QD heterostructure exhibits significantly enhanced photocatalytic performance for the degradation of organic pollutants under visible light irradiation in comparison with blank TiO2 NBs and randomly mixed counterparts. The significantly enhanced photocatalytic performance of the TiO2 NB–CdS QD heterostructure can be attributed to the synergistic contribution from the enhanced light absorption intensity of the hybrid nanocomposite and intimate interfacial contact between CdS QD and TiO2 NB ingredients afforded by the electrostatic self-assembly buildup, which remarkably facilitates charge separation and lengthens the lifetime of photogenerated electron–hole pairs under visible light irradiation. Moreover, it was demonstrated that the TiO2 NB–CdS QD heterostructure shows favorable photostability on account of intrinsic protection by a surface ligand of CdS QDs. In addition, the possible photocatalytic mechanism was tentatively proposed and predominant active species during the photocatalytic process were unambiguously determined.
Co-reporter:Rong Chen, Hsin-Yi Wang, Jianwei Miao, Hongbin Yang, Bin Liu
Nano Energy 2015 Volume 11() pp:333-340
Publication Date(Web):January 2015
DOI:10.1016/j.nanoen.2014.11.021
Three-dimensional NiCo2O4 core-shell nanowires made up of NiCo2O4 nanowire core and NiCo2O4 nanoflake shell have been fabricated by a simple two-step wet chemical method on flexible conductive carbon cloth substrate for oxygen evolution reaction (OER). The combination of high surface area, enhanced mass and charge transport as well as three-dimensional conducting pathway enables superior oxygen evolution reaction. Notably, the NiCo2O4 core-shell nanowire electrode exhibits large anodic current and low onset overpotential for OER with an overpotential of~320 mV at a current density of 10 mA/cm2. Furthermore, the NiCo2O4 core-shell nanowire electrode possesses excellent electrocatalytic stability with long hour electrolysis showing no visible degradation, which is highly desirable for a promising OER electrocatalyst.
Co-reporter:Jianwei Miao;Hong Bin Yang;Fang-Xing Xiao;Si Yun Khoo;Jiazang Chen;Zhanxi Fan;Ying-Ya Hsu;Hua Zhang;Hao Ming Chen
Science Advances 2015 Volume 1(Issue 7) pp:e1500259
Publication Date(Web):21 Aug 2015
DOI:10.1126/sciadv.1500259
A flexible cloth-like electrode, which can efficiently split water to produce H2 at neutral pH, is successfully demonstrated.
Co-reporter:Lei Zhang, Hao Bin Wu, Bin Liu and Xiong Wen (David) Lou
Energy & Environmental Science 2014 vol. 7(Issue 3) pp:1013-1017
Publication Date(Web):02 Jan 2014
DOI:10.1039/C3EE43305F
Porous SnO2 microboxes with a high uniformity and well-defined non-spherical hollow structure are prepared via a selective leaching strategy using ZnSn(OH)6 microboxes as the starting material. The selective removal of Zn(II) species by an acid-washing process produces pure SnO2 microboxes with a porous shell. After further wrapping with an elastic carbon matrix, the resultant SnO2@C microboxes exhibit excellent electrochemical performance as an anode material for lithium-ion batteries.
Co-reporter:Fang-Xing Xiao ; Jianwei Miao
Journal of the American Chemical Society 2014 Volume 136(Issue 4) pp:1559-1569
Publication Date(Web):January 6, 2014
DOI:10.1021/ja411651e
In recent years, increasing interest has been devoted to synthesizing graphene–semiconductor nanocomposites as efficient photocatalysts for extensive applications. Unfortunately, it is still challenging to make uniform graphene–semiconductor composite films with controllable film thickness and architecture, which are of paramount importance to meet the application requirements. In this work, stable aqueous dispersion of polymer-modified graphene nanosheets (GNs) was prepared via in situ reduction of exfoliated graphite oxide in the presence of cationic poly(allylamine hydrochloride) (PAH). The resultant water-soluble PAH-modified GNs (GNs-PAH) in conjunction with tailor-made negatively charged CdS quantum dots (QDs) were utilized as nanobuilding blocks for sequential layer-by-layer (LbL) self-assembly of well-defined GNs–CdS QDs hybrid films, in which CdS QDs overspread evenly on the two-dimensional (2D) GNs. It was found that the alternating GNs–CdS QDs multilayered films showed significantly enhanced photoelectrochemical and photocatalytic activities under visible light irradiation as compared to pure CdS QDs and GNs films. The enhancement was attributed to the judicious integration of CdS QDs with GNs in an alternating manner, which maximizes the 2D structural advantage of GNs in GNs–CdS QDs composite films. In addition, photocatalytic and photoelectrochemical mechanisms of the GNs–CdS QDs multilayered films were also discussed. It is anticipated that our work may open new directions for the fabrication of uniform semiconductor/GNs hybrid films for a wide range of applications.
Co-reporter:Jiazang Chen ; Hong Bin Yang ; Jianwei Miao ; Hsin-Yi Wang
Journal of the American Chemical Society 2014 Volume 136(Issue 43) pp:15310-15318
Publication Date(Web):October 7, 2014
DOI:10.1021/ja5080568
In photoelectrochemical cells, there exists a competition between transport of electrons through the porous semiconductor electrode toward the conducting substrate and back-reaction of electrons to recombine with oxidized species on the semiconductor–electrolyte interface, which determines the charge collection efficiency and is strongly influenced by the density and distribution of electronic states in band gap and architectures of the semiconductor electrodes. One-dimensional (1D) anatase TiO2 nanostructures are promising to improve charge transport in photoelectrochemical devices. However, the conventional preparation of 1D anatase nanostructures usually steps via a titanic acid intermediate (e.g., H2Ti3O7), which unavoidably introduces electronic defects into the host lattice, resulting in undesired shielding of the intrinsic role of dimensionality. Here, we manage to promote the 1D growth of anatase TiO2 nanostructures by adjusting the growth kinetics, which allows us to grow single-crystalline anatase TiO2 nanorods through a one-step hydrothermal reaction. The synthesized anatase nanorods possess a lower density of trap states and thus can simultaneously facilitate the diffusion-driven charge transport and suppress the electron recombination. Moreover, the electronically boundary free nanostructures significantly enhance the trap-free charge diffusion coefficient of the anatase nanorods, which enables the emergence of the intrinsic superiority of dimensionality. By virtue of these merits, the anatase nanorods synthesized in this work take obvious advantages over the conventional anatase counterparts in photoelectrochemical systems (e.g., dye-sensitized solar cells) by showing more efficient charge transport and collection and higher energy conversion efficiency.
Co-reporter:Fang-Xing Xiao, Jianwei Miao and Bin Liu
Materials Horizons 2014 vol. 1(Issue 2) pp:259-263
Publication Date(Web):02 Oct 2013
DOI:10.1039/C3MH00097D
A novel self-assembly approach based on electrostatic interactions has been developed for the synthesis of a rutile@anatase TiO2 nanorod (NR)@CdS quantum dots (QDs) ternary core–shell heterostructure, in which an in situ formed monodisperse anatase TiO2 layer was intimately sandwiched between rutile TiO2 NRs and CdS QDs. It has been demonstrated that the well-defined bilayer interface significantly improves the photocatalytic performance of the ternary heterostructure (i.e. rutile@anatase TiO2 NR@CdS QDs), owing predominantly to the appropriate band alignment of the constituent semiconductors, thus facilitating photogenerated electron–hole separation and charge collection under simulated solar light irradiation.
Co-reporter:Junyu Zhang, Fang-Xing Xiao, Guangcan Xiao and Bin Liu
Nanoscale 2014 vol. 6(Issue 19) pp:11293-11302
Publication Date(Web):25 Jul 2014
DOI:10.1039/C4NR03115F
In recent years, tremendous research efforts have been made towards developing graphene (GR)-based nanocomposites for photocatalytic applications. In this work, surface-coarsened TiO2 nanobelts (SC-TNBs) closely enwrapped with monodispersed Ag nanoparticles (NPs) and GR nanosheets (i.e. Ag/GR/SC-TNBs) were fabricated using a facile self-assembly strategy followed by photoreduction. It was found that the as-prepared Ag/GR/SC-TNBs ternary heterostructure exhibited significantly improved photocatalytic performances under irradiation with UV light in comparison with blank SC-TNBs and its binary counterparts owing to the formation of double heterojunctions among the components. The intimate integration of Ag NPs and GR with SC-TNBs achieved by the self-assembly buildup exerts a profound effect on the transfer of photogenerated electrons over the SC-TNBs substrate in which Ag NPs serve as an efficient “electron reservoir” and GR as an electron transporter and collector, thus concurrently prolonging the lifetime of the photogenerated electron–hole pairs and resulting in the remarkably enhanced photoactivity over the Ag/GR/SC-TNBs ternary nanocomposite. In addition, the underlying photocatalytic mechanism was elucidated and the primary active species were determined.
Co-reporter:Hsin-Yi Wang, Jiazang Chen, Sunny Hy, Linghui Yu, Zhichuan Xu and Bin Liu
Nanoscale 2014 vol. 6(Issue 24) pp:14926-14931
Publication Date(Web):09 Oct 2014
DOI:10.1039/C4NR04729J
Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m2 g−1 were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity.
Co-reporter:Fang-Xing Xiao, Sung-Fu Hung, Hua Bing Tao, Jianwei Miao, Hong Bin Yang and Bin Liu
Nanoscale 2014 vol. 6(Issue 24) pp:14950-14961
Publication Date(Web):09 Oct 2014
DOI:10.1039/C4NR04886E
Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure–property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron–hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D–1D hybrid nanocomposites for extensive photocatalytic applications.
Co-reporter:Hong Bin Yang, Yong Qiang Dong, Xizu Wang, Si Yun Khoo, and Bin Liu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 2) pp:1092
Publication Date(Web):December 24, 2013
DOI:10.1021/am404638e
Solution processable inverted bulk heterojunction (BHJ) polymer solar cells (PSCs) are promising alternatives to conventional silicon solar cells because of their low cost roll-to-roll production and flexible device applications. In this work, we demonstrated that Cs2CO3 functionalized graphene quantum dots (GQDs–Cs2CO3) could be used as efficient electron-selective layers in inverted PSCs. Compared with Cs2CO3 buffered devices, the GQDs–Cs2CO3 buffered devices show 56% improvement in power conversion efficiency, as well as 200% enhancement in stability, due to the better electron-extraction, suppression of leakage current, and inhibition of Cs+ ion diffusion at the buffer/polymer interface by GQDs–Cs2CO3. This work provides a thermal-annealing-free, solution-processable method for fabricating electron-selective layer in inverted PSCs, which should be beneficial for the future development of high performance all-solution-processed or roll-to-roll processed PSCs.Keywords: cathode buffer; cesium carbonate; graphene; polymer solar cells; quantum dots; stability;
Co-reporter:Gang Li, Jianwei Miao, Jun Cao, Jia Zhu, Bin Liu and Qichun Zhang
Chemical Communications 2014 vol. 50(Issue 57) pp:7656-7658
Publication Date(Web):28 May 2014
DOI:10.1039/C4CC02908A
Photoelectrochemical studies demonstrated that 1,4,6,8,11,13-hexazapentacene (HAP) exhibited active n-type semiconductor behavior under visible light (λ > 400 nm) illumination.
Co-reporter:Junkuo Gao, Jianwei Miao, Pei-Zhou Li, Wen Yuan Teng, Ling Yang, Yanli Zhao, Bin Liu and Qichun Zhang
Chemical Communications 2014 vol. 50(Issue 29) pp:3786-3788
Publication Date(Web):04 Feb 2014
DOI:10.1039/C3CC49440C
Here, we report a new Ti(IV)-based porous metal–organic framework (MOF) (NTU-9), which displayed strong absorption in the visible region with a bandgap of 1.72 eV. The electronic structure and bandgap were further investigated by DFT calculations. Photoelectrochemical studies indicated that NTU-9 is photoactive under visible light illumination (λ > 400 nm) and acts as a p-type semiconductor. The results demonstrated that Ti(IV)-based MOFs could be promising visible-light photocatalysts for energy conversion and environmental remediation.
Co-reporter:Bin Liu, Cheng-Hao Wu, Jianwei Miao, and Peidong Yang
ACS Nano 2014 Volume 8(Issue 11) pp:11739
Publication Date(Web):November 3, 2014
DOI:10.1021/nn5051954
The generation of chemical fuels via direct solar-to-fuel conversion from a fully integrated artificial photosynthetic system is an attractive approach for clean and sustainable energy, but so far there has yet to be a system that would have the acceptable efficiency, durability and can be manufactured at a reasonable cost. Here, we show that a semiconductor mesh made from all inorganic nanowires can achieve unassisted solar-driven, overall water-splitting without using any electron mediators. Free-standing nanowire mesh networks could be made in large scales using solution synthesis and vacuum filtration, making this approach attractive for low cost implementation.Keywords: artificial photosynthesis; BiVO4; Rh-SrTiO3; semiconductor nanowire; solar water splitting;
Co-reporter:Hong Bin Yang, Jianwei Miao, Sung-Fu Hung, Fengwei Huo, Hao Ming Chen, and Bin Liu
ACS Nano 2014 Volume 8(Issue 10) pp:10403
Publication Date(Web):September 30, 2014
DOI:10.1021/nn503751s
Sunlight is an ideal source of energy, and converting sunlight into chemical fuels, mimicking what nature does, has attracted significant attention in the past decade. In terms of solar energy conversion into chemical fuels, solar water splitting for hydrogen production is one of the most attractive renewable energy technologies, and this achievement would satisfy our increasing demand for carbon-neutral sustainable energy. Here, we report corrosion-resistant, nanocomposite photoelectrodes for spontaneous overall solar water splitting, consisting of a CdS quantum dot (QD) modified TiO2 photoanode and a CdSe QD modified NiO photocathode, where cadmium chalcogenide QDs are protected by a ZnS passivation layer and gas evolution cocatalysts. The optimized device exhibited a maximum efficiency of 0.17%, comparable to that of natural photosynthesis with excellent photostability under visible light illumination. Our device shows spontaneous overall water splitting in a nonsacrificial environment under visible light illumination (λ > 400 nm) through mimicking nature’s “Z-scheme” process. The results here also provide a conceptual layout to improve the efficiency of solar-to-fuel conversion, which is solely based on facile, scalable solution-phase techniques.Keywords: photoelectrochemical cell; quantum dots; semiconductor; water splitting;
Co-reporter:Qian Zhang, Hsin-Yi Wang, Xinli Jia, Bin Liu and Yanhui Yang
Nanoscale 2013 vol. 5(Issue 16) pp:7175-7183
Publication Date(Web):07 Jun 2013
DOI:10.1039/C3NR02030D
Metal oxides are of paramount importance in heterogeneous catalysis as either supports or active phases. Controlled synthesis of one-dimensional (1D) metal oxide nanostructures has received enormous attention in heterogeneous catalysis due to the possibility of tailoring the properties of metal oxides by tuning their shapes, sizes, and compositions. This feature article highlights recent advances in shape controlled synthesis of 1D metal oxide nanostructures and their applications in heterogeneous catalysis, with the aim of introducing new insights into the heterogeneous catalyst design.
Co-reporter:Fang-Xing Xiao, Jianwei Miao, Hsin-Yi Wang and Bin Liu
Journal of Materials Chemistry A 2013 vol. 1(Issue 39) pp:12229-12238
Publication Date(Web):12 Aug 2013
DOI:10.1039/C3TA12856C
In recent years, much attention has been focused on the preparation of CdS–TiO2 nanotube array (CdS–TNTA) hybrid nanomaterials. Nevertheless, it is still challenging to synthesize hierarchically ordered CdS–TNTA heterostructures as efficient photocatalysts via a facile and simple approach. In this work, tailor-made negatively charged CdS quantum dots (QDs) are evenly deposited on a hierarchical framework of TiO2 nanotube arrays, consisting of periodically ordered nanorings on the surface and nanotubes underneath, by modulating the surface charge properties of the constituents. It has been demonstrated that the CdS–nanoporous TiO2 nanotube array (CdS–NP-TNTA) hybrid nanostructures exhibit promising visible-light photoactivity towards the photooxidation of organic dye pollutants and the photocatalytic reduction of nitrophenol derivatives as a result of the monodisperse deposition of CdS QDs on the well-defined NP-TNTA scaffold. Photoelectrochemical investigations have shown the significantly enhanced separation efficiency of photogenerated electron–hole charge carriers in the CdS–NP-TNTA heterostructure under visible light irradiation. Furthermore, the self-assembled CdS–NP-TNTA heterostructure demonstrates improved photostability. Our work should provide a new paradigm to prepare hierarchically ordered narrow band-gap semiconductor/one-dimensional semiconductor nanomaterials for efficient visible light-driven photocatalysis.
Co-reporter:Jianwei Miao, Hong Bin Yang, Si Yun Khoo and Bin Liu
Nanoscale 2013 vol. 5(Issue 22) pp:11118-11124
Publication Date(Web):29 Aug 2013
DOI:10.1039/C3NR03425A
Efficient hydrogen production from photoelectrochemical (PEC) water splitting is a promising route to solve the approaching energy crisis. Herein, we report a facile all-electrochemical approach to fabricate well-aligned ZnO–CdSe core–shell nanorod arrays with excellent uniformity on transparent indium tin oxide (ITO) substrates. The shell thickness of the core–shell nanorods can be tuned precisely by adjusting the charge density passing through the working electrode during the deposition of CdSe quantum dots (QDs). The optimized ZnO–CdSe nanorod arrays showed excellent PEC performance with a significant saturated photocurrent density of 14.9 mA cm−2 at 0.8 V (vs. RHE) under AM 1.5 illumination, which is, to the best of our knowledge, the highest value ever reported for similar nanostructures, owing to the favourable band alignment and good distribution of CdSe QDs on ZnO nanorods. Our results demonstrate that the electrochemically deposited ZnO–CdSe nanorod arrays can be utilized as efficient photoanodes in PEC water splitting cells.
Co-reporter:Hong Bin Yang, Yong Qian Dong, Xizu Wang, Si Yun Khoo, Bin Liu, Chang Ming Li
Solar Energy Materials and Solar Cells 2013 Volume 117() pp:214-218
Publication Date(Web):October 2013
DOI:10.1016/j.solmat.2013.05.060
•The application of Graphene quantum dots (GQDs) in PSCs was investigated.· GQDs additive enhanced the exciton dissociation and suppressed charge recombination.· The PCE of GQDs-Cs2CO3 based device showed 22 % enhancement from 2.59% to 3.17%.· This work provides a new application of GQDs in organic electronic devices.Graphene quantum dots (GQDs) are an emerging class of nanomaterials with unique photonic and electric properties. In this study, GQDs were prepared by a facile, inexpensive and high-yield hydrothermal method and were further used as a cathode buffer additive for inverted polymer solar cells due to a wide band gap (~3.3 eV) and well-matched energy level between GQDs–cesium carbonate (GQDs–Cs2CO3) modified indium tin oxide (3.8 eV) and high occupied molecular orbit of [6,6]-phenyl-C61-butyric acid methyl ester (3.7 eV). In comparison to inverted polymer solar cells using cesium carbonate (Cs2CO3) buffer layer, the power conversion efficiency of GQDs–Cs2CO3 based device showed 22% enhancement from 2.59% to 3.17% as a result of enhanced exciton dissociation and suppressed free charge recombination at cathode/polymer active layer interface by GQDs. This work provides a new application of GQDs in organic electronic devices.
Co-reporter:Shiming Zhang, Bin Liu and Shengli Chen
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 42) pp:18482-18490
Publication Date(Web):10 Sep 2013
DOI:10.1039/C3CP53760A
A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption–desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe–N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe–N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.
Co-reporter:Jianwei Miao and Bin Liu
RSC Advances 2013 vol. 3(Issue 4) pp:1222-1226
Publication Date(Web):15 Nov 2012
DOI:10.1039/C2RA22312K
Anatase TiO2 microspheres with a high percentage (>90%) of exposed high-reactivity {001} facets were synthesized using hydrofluoric acid generated in situ through hydrolysis of titanium tetrafluoride (TiF4) as a capping and stabilizing agent without introducing any additional hydrofluoric acid under hydrothermal conditions. The as-prepared TiO2 microspheres show excellent photocatalytic activity in the degradation of toxic organic contaminants as well as production of hydrogen in water under UV light irradiation.
Co-reporter:Bin Liu
Nanoscale 2012 vol. 4(Issue 22) pp:7194-7198
Publication Date(Web):21 Sep 2012
DOI:10.1039/C2NR32439C
I report a facile wet-chemical method for the synthesis of one-dimensional copper hydroxide nitrate nanostructures in 2-propanol under solvothermal conditions. Single-crystalline nearly monodispersed copper hydroxide nitrate nanorods and nanobelts with selected breadths in the range of 100 nm to 1 μm have been successfully prepared by a solvothermal method through controlling the experimental parameters, including initial concentrations of reagents, reaction temperature, solvent and reaction time. The resultant nanorods and nanobelts were characterized using FESEM, TEM, XRD, FTIR and TGA techniques. Upon thermal calcination, the copper hydroxide nitrate nanorods and nanobelts self-assemble into one-dimensional arrays (rods, belts or tubes) of copper oxide nanoparticles. The as-prepared copper hydroxide nitrate nanorods and nanobelts were tested as ion exchangers for removal of long-lived radioactive anions such as 129I− and 99TcO4−. The copper hydroxide nitrate nanorods or nanobelts were over two times more active in the removal of anion species than copper hydroxide nitrate nanoplatelets.
Co-reporter:Jiajian Gao, Chunmiao Jia, Liping Zhang, Hongming Wang, Yanhui Yang, Sung-Fu Hung, Ying-Ya Hsu, Bin Liu
Journal of Catalysis (September 2016) Volume 341() pp:82-90
Publication Date(Web):1 September 2016
DOI:10.1016/j.jcat.2016.06.009
•Fe-, Co-, Ni-, and Cu-doped α-MnO2 nanowires were synthesized by a one-step hydrothermal method.•All doped MnO2 nanowires exhibited much enhanced CO oxidation activity.•The Cu-doped MnO2 nanowires had a maximum TOF of 9.1 × 10−3 s−1 at 70 °C.•Cu-doped MnO2 could maintain 50 h without obvious deactivation with 2% water moisture.•Cu doping makes the formation of oxygen vacancies easier in MnO2.Replacing a small fraction of cations in a host metal oxide with a different cation (also known as doping) provides a useful strategy for improving the catalytic activity. Here, we report transition metal (Fe, Co, Ni, and Cu)-doped α-MnO2 nanowires synthesized by a one-step hydrothermal method as CO oxidation catalysts. The as-prepared catalysts displayed morphology, crystal structure, and specific surface area similar to those of the pure MnO2 nanowires. A catalytic activity test showed that all doped MnO2 nanowires exhibited much enhanced CO oxidation activity, with the Cu-doped ones being the most active (TOF of 9.1 × 10−3 s−1 at 70 °C). The Cu-doped MnO2 nanowires showed nearly 100% conversion of CO at 100 °C at an hourly gas space velocity of 36,000 mL g−1 h−1, which could last for 50 h without obvious deactivation even in the presence of 2% water vapor. Density functional theory calculations suggested that Cu doping could make the formation of oxygen vacancies in MnO2, which is the rate-determining step for CO oxidation reaction, easier than for Fe-, Co-, and Ni-doped and pristine MnO2. Our work demonstrates a facile and promising strategy for improving the catalytic activity for oxide-based catalysts, which should be applicable for a variety of different chemical reactions.Download high-res image (138KB)Download full-size image
Co-reporter:Hong Bin Yang, Yong Qian Dong, Xizu Wang, Si Yun Khoo, Bin Liu, Chang Ming Li
Solar Energy Materials and Solar Cells (October 2013) Volume 117() pp:214-218
Publication Date(Web):1 October 2013
DOI:10.1016/j.solmat.2013.05.060
•The application of Graphene quantum dots (GQDs) in PSCs was investigated.· GQDs additive enhanced the exciton dissociation and suppressed charge recombination.· The PCE of GQDs-Cs2CO3 based device showed 22 % enhancement from 2.59% to 3.17%.· This work provides a new application of GQDs in organic electronic devices.Graphene quantum dots (GQDs) are an emerging class of nanomaterials with unique photonic and electric properties. In this study, GQDs were prepared by a facile, inexpensive and high-yield hydrothermal method and were further used as a cathode buffer additive for inverted polymer solar cells due to a wide band gap (~3.3 eV) and well-matched energy level between GQDs–cesium carbonate (GQDs–Cs2CO3) modified indium tin oxide (3.8 eV) and high occupied molecular orbit of [6,6]-phenyl-C61-butyric acid methyl ester (3.7 eV). In comparison to inverted polymer solar cells using cesium carbonate (Cs2CO3) buffer layer, the power conversion efficiency of GQDs–Cs2CO3 based device showed 22% enhancement from 2.59% to 3.17% as a result of enhanced exciton dissociation and suppressed free charge recombination at cathode/polymer active layer interface by GQDs. This work provides a new application of GQDs in organic electronic devices.
Co-reporter:Jianwei Miao, Bin Liu
Journal of Energy Chemistry (May 2016) Volume 25(Issue 3) pp:371-374
Publication Date(Web):1 May 2016
DOI:10.1016/j.jechem.2016.02.013
Cadmium selenide (CdSe)-sensitized upright-standing mesoporous zinc oxide (ZnO) nanosheets were prepared via a chemical bath deposition followed by annealing and electrochemical deposition of CdSe quantum dots (QDs). The CdSe QDs absorb visible photons under sunlight illumination, promoting electrons from the valence band to the conduction band of CdSe, which then quickly transfer to ZnO followed by the external load to the Pt counter electrode for water reduction. The as-prepared CdSe/ZnO nanosheets show promising photoelectrochemical activities for hydrogen generation.Cadmium selenide-sensitized upright-standing ZnO nanosheets can be fabricated using a facile all solution-phase approach. As a photoanode, the CdSe-sensitized ZnO nanosheets demonstrated significantly enhanced performance in photoelectrochemical hydrogen production. Download full-size image
Co-reporter:Junyu Zhang, Fang-Xing Xiao, Guangcan Xiao, Bin Liu
Applied Catalysis A: General (5 July 2016) Volume 521() pp:50-56
Publication Date(Web):5 July 2016
DOI:10.1016/j.apcata.2015.10.046
Co-reporter:Hsin-Yi Wang, Jiazang Chen, Fang-Xing Xiao, Jianwei Zheng and Bin Liu
Journal of Materials Chemistry A 2016 - vol. 4(Issue 18) pp:NaN6932-6932
Publication Date(Web):2015/10/30
DOI:10.1039/C5TA08202A
Semiconductor nanostructures with specially exposed reactive crystal facets are promising to promote photocatalytic/photoelectrochemical reactions. Here, we demonstrate that the introduction of niobium into TiO2 can modify TiO2 surface chemistry, which in turn influences the growth of TiO2 nanostructures from one-dimensional rutile nanorods at a low niobium doping concentration to two-dimensional anatase nanosheets at a high niobium doping concentration. Additionally, the electronic structure, optical properties, and surface activity for O2 adsorption are substantially influenced for Nb-doped TiO2 by electron donation from the niobium dopant, which significantly enhances the light-induced generation of super oxide radicals (O2−˙), and thus improves the photocatalytic activity of Nb-doped TiO2.
Co-reporter:Shiming Zhang, Bin Liu and Shengli Chen
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 42) pp:NaN18490-18490
Publication Date(Web):2013/09/10
DOI:10.1039/C3CP53760A
A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption–desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe–N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe–N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.
Co-reporter:Junbo Li, Jianwei Miao, Guankui Long, Jing Zhang, Yongxin Li, Rakesh Ganguly, Yang Zhao, Yi Liu, Bin Liu and Qichun Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 38) pp:NaN9884-9884
Publication Date(Web):2015/08/27
DOI:10.1039/C5TC02010G
N-heteroquinones with both quinone and pyrazine as electron-withdrawing moieties can be potential candidates for n-type organic semiconductor materials. Here, two novel soluble N-heteroquinones: 5,9,14,18-tetra-((triisopropylsilyl)ethynyl)-6,8,15,17-tetraazaheptacene-7,16-dione (TAHD) and 6,10,17,21-tetra-((triisopropylsilyl)ethynyl)-7,9,18,20-tetraazanonacene-8,19-dione (TAND) with different lengths have been synthesized and their structures were fully characterized by 1H NMR, 13C NMR, HRMS and single crystal analysis. Our studies showed that the shorter TAHD molecules are planar in the solid state without intermolecular π–π stacking and the main force to stabilize the packing is the C–H–π interaction between (triisopropylsilyl)ethynyl (TIPS) groups and the backbones. Differently, the larger TAND molecules show slightly twisted structures with the anthracene units bent down and up on the two sites and the dihedral angle between the quinone unit and the anthracene unit is 6.7°. Meanwhile, TAND molecules adopt face-to-face two-dimensional (2D) brickwork arrangement, and the distances between π planes are 3.63 and 3.38 nm, respectively, suggesting the existence of π–π interactions. The visible-light-driven photoelectrochemical behaviors showed that both TAHD and TAND are n-type semiconductors. However, TAHD shows unstable photovoltage response and lower photocurrent due to the absence of π–π interaction while TAND shows stable photovoltage response and a relatively high photocurrent. Our results suggested that the length of the linear N-heteroquinones has large effects on their physical properties, crystal packing and photoelectrochemical behaviors.
Co-reporter:Pei-Yang Gu, Zilong Wang, Fang-Xing Xiao, Zongqiong Lin, Rongbin Song, Qing-Feng Xu, Jian-Mei Lu, Bin Liu and Qichun Zhang
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 3) pp:NaN498-498
Publication Date(Web):2016/08/23
DOI:10.1039/C6QM00113K
Present photoelectrochemical (PEC) cells for water splitting are based on inorganic electrodes. For future large-scale applications, electrodes that are metal-free, of low cost, and with sustainable availability are crucial. Herein, we report a new ambipolar larger azaacene (DQNDN) as a single-active-element-based photocathode in PEC cells with a current density of 0.13 mA cm−2 at −0.13 V versus RHE.
Co-reporter:Junkuo Gao, Jianwei Miao, Pei-Zhou Li, Wen Yuan Teng, Ling Yang, Yanli Zhao, Bin Liu and Qichun Zhang
Chemical Communications 2014 - vol. 50(Issue 29) pp:NaN3788-3788
Publication Date(Web):2014/02/04
DOI:10.1039/C3CC49440C
Here, we report a new Ti(IV)-based porous metal–organic framework (MOF) (NTU-9), which displayed strong absorption in the visible region with a bandgap of 1.72 eV. The electronic structure and bandgap were further investigated by DFT calculations. Photoelectrochemical studies indicated that NTU-9 is photoactive under visible light illumination (λ > 400 nm) and acts as a p-type semiconductor. The results demonstrated that Ti(IV)-based MOFs could be promising visible-light photocatalysts for energy conversion and environmental remediation.
Co-reporter:Junyu Zhang, Guangcan Xiao, Fang-Xing Xiao and Bin Liu
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 2) pp:NaN250-250
Publication Date(Web):2016/09/16
DOI:10.1039/C6QM00141F
One-dimensional (1D) TiO2 nanostructures have been regarded as ideal candidates for solar energy conversion due to their unique structural merits including large surface-to-volume ratio, fast and long-distance charge transport, and good physi-co-chemical stability. Over the past few decades, tremendous interest has been devoted to fabricating a large number of 1D TiO2 based heterostructures for extensive photocatalytic applications. In this review article, we provide a comprehensive and systematic discussion on the latest developments of a large variety of 1D TiO2 based composite heterostructures along with their versatile photocatalytic applications in various research fields including nonselective photodegradation of organic pollutants for environmental remediation, photocatalytic selective organic transformation, as well as solar energy conversion for fuel production. Furthermore, future challenges and promising perspectives for this increasingly booming photocatalytic technology are also presented. It is anticipated that this review article will provide enriched and useful information on rational utilization of the outstanding structure and electronic properties of 1D TiO2 nanostructures for a wide range of photocatalytic applications.
Co-reporter:Gang Li, Jianwei Miao, Jun Cao, Jia Zhu, Bin Liu and Qichun Zhang
Chemical Communications 2014 - vol. 50(Issue 57) pp:NaN7658-7658
Publication Date(Web):2014/05/28
DOI:10.1039/C4CC02908A
Photoelectrochemical studies demonstrated that 1,4,6,8,11,13-hexazapentacene (HAP) exhibited active n-type semiconductor behavior under visible light (λ > 400 nm) illumination.
Co-reporter:Junkuo Gao, Jianwei Miao, Yongxin Li, Rakesh Ganguly, Yang Zhao, Ovadia Lev, Bin Liu and Qichun Zhang
Dalton Transactions 2015 - vol. 44(Issue 32) pp:NaN14358-14358
Publication Date(Web):2015/07/07
DOI:10.1039/C5DT01769F
A simple and facile one-step method for the synthesis of an organic dye-functionalized polyoxometalate (POM) hybrid with visible-light photo-response was reported. The POM hybrid was fully characterized via single crystal XRD, powder XRD, FTIR and elemental analysis. The reaction of the organic dye with inorganic salts gave the dye-functionalized POM (MoBB3), in which the POM cluster was formed in situ. The electronic absorption peak of this hybrid was successfully extended beyond 680 nm. Photoelectrochemical measurement indicated that MoBB3 was photoresponsive under visible-light illumination, suggesting that it is an n-type (electron conductive) semiconducting material. This result might offer a method for the design of novel organic dye-functionalized POMs for photoelectric applications.
Co-reporter:Fang He, Gang Chen, Yansong Zhou, Yaoguang Yu, Laiquan Li, Sue Hao and Bin Liu
Journal of Materials Chemistry A 2016 - vol. 4(Issue 10) pp:NaN3827-3827
Publication Date(Web):2016/02/03
DOI:10.1039/C6TA00497K
A ZIF-8 derived carbon (C-ZIF)/g-C3N4 composite was constructed for the first time through facile thermal condensation of a zeolitic imidazolate framework (ZIF-8) and melamine. The obtained C-ZIF/g-C3N4 composite exhibited an obviously enhanced photocatalytic H2 production rate compared to pure g-C3N4 under visible light irradiation. The 1 wt% C-ZIF/g-C3N4 composite without loading the Pt co-catalyst showed 36.2 times higher H2 evolution rate than that of pure g-C3N4, which is even 2.8 times higher than that of Pt/g-C3N4 (the state-of-the-art g-C3N4-based photocatalyst). It was revealed by photoluminescence spectroscopy, time-resolved fluorescence spectroscopy and electrochemical impedance spectroscopy that the formed C-ZIF and g-C3N4 junction could promote quick charge carrier separation and transfer. The C-ZIF not only acted as an effective electron acceptor, but also functioned as an efficient hydrogen evolution reaction (HER) cocatalyst to promote photocatalytic hydrogen evolution. Our work provides an effective way for the development of metal-free, all carbon-based photocatalysts for H2 evolution.
Co-reporter:Fang-Xing Xiao, Mario Pagliaro, Yi-Jun Xu and Bin Liu
Chemical Society Reviews 2016 - vol. 45(Issue 11) pp:NaN3121-3121
Publication Date(Web):2016/03/22
DOI:10.1039/C5CS00781J
Over the past few decades, layer-by-layer (LbL) assembly of multilayer thin films has garnered considerable interest on account of its ability to modulate nanometer control over film thickness and its extensive choice of usable materials for coating planar and particulate substrates, thus allowing for the fabrication of responsive and functional thin films for their potential applications in a myriad of fields. Herein, we provide elaborate information on the current developments of LbL assembly techniques including different properties, molecular interactions, and assembly methods associated with this promising bottom-up strategy. In particular, we highlight the principle for rational design and fabrication of a large variety of multilayer thin film systems including multi-dimensional capsules or spatially hierarchical nanostructures based on the LbL assembly technique. Moreover, we discuss how to judiciously choose the building block pairs when exerting the LbL assembly buildup which enables the engineering of multilayer thin films with tailor-made physicochemical properties. Furthermore, versatile applications of the diverse LbL-assembled nanomaterials are itemized and elucidated in light of specific technological fields. Finally, we provide a brief perspective and potential future challenges of the LbL assembly technology. It is anticipated that our current review could provide a wealth of guided information on the LbL assembly technique and furnish firm grounds for rational design of LbL assembled multilayer assemblies toward tangible applications.
Co-reporter:Yibo Yan, Jianwei Miao, Zhihong Yang, Fang-Xing Xiao, Hong Bin Yang, Bin Liu and Yanhui Yang
Chemical Society Reviews 2015 - vol. 44(Issue 10) pp:NaN3346-3346
Publication Date(Web):2015/04/09
DOI:10.1039/C4CS00492B
Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.
Co-reporter:Fang-Xing Xiao, Jianwei Miao, Hsin-Yi Wang and Bin Liu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 39) pp:NaN12238-12238
Publication Date(Web):2013/08/12
DOI:10.1039/C3TA12856C
In recent years, much attention has been focused on the preparation of CdS–TiO2 nanotube array (CdS–TNTA) hybrid nanomaterials. Nevertheless, it is still challenging to synthesize hierarchically ordered CdS–TNTA heterostructures as efficient photocatalysts via a facile and simple approach. In this work, tailor-made negatively charged CdS quantum dots (QDs) are evenly deposited on a hierarchical framework of TiO2 nanotube arrays, consisting of periodically ordered nanorings on the surface and nanotubes underneath, by modulating the surface charge properties of the constituents. It has been demonstrated that the CdS–nanoporous TiO2 nanotube array (CdS–NP-TNTA) hybrid nanostructures exhibit promising visible-light photoactivity towards the photooxidation of organic dye pollutants and the photocatalytic reduction of nitrophenol derivatives as a result of the monodisperse deposition of CdS QDs on the well-defined NP-TNTA scaffold. Photoelectrochemical investigations have shown the significantly enhanced separation efficiency of photogenerated electron–hole charge carriers in the CdS–NP-TNTA heterostructure under visible light irradiation. Furthermore, the self-assembled CdS–NP-TNTA heterostructure demonstrates improved photostability. Our work should provide a new paradigm to prepare hierarchically ordered narrow band-gap semiconductor/one-dimensional semiconductor nanomaterials for efficient visible light-driven photocatalysis.
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