Electrochemical hydrogenation of mixed-phase TiO2 nanotube arrays enables remarkably enhanced photoelectrochemical water splitting performance  

作　　者：Jiaqin Liu Mengjia Dai Jian Wu Ying Hu Qi Zhang Jiewu Cui Yan Wang Hark Hoe Tan Yucheng Wu 

机构地区：[1]Institute of Industry and Equipment Technology, Hefei University of Technology, Hefei 230009, China [2]School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China [3]Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009, China [4]Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT2601, Australia

出　　处：《Science Bulletin》2018年第3期194-202,共9页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(51402078,21702041,and 11674354);the National Basic Research Program of China(2014CB660815);the Fundamental Research Funds for the Central Universities(JZ2016HGTB0711,JZ2016HGTB0719,and JZ2017HGPA0167)

摘　　要：We first report that photoelectrochemical （PEC） performance of electrochemically hydrogenated TiO2 nanotube arrays （TNTAs） as high-efficiency photoanodes for solar water splitting could be well tuned by designing and adjusting the phase structure and composition of TNTAs. Among various TNTAs annealed at different temperature ranging from 300 to 700℃, well-crystallized single anatase （A） phase TNTAs-400 photoanode shows the best photoresponse properties and PEC performance due to the favor- able crystallinity, grain size and tubular structures. After electrochemical hydrogenation （EH）. anatase- rutile （A-R） mixed phase EH-TNTAs-600 photoanode exhibits the highest photoactivity and PEC perfor- mance for solar water splitting. Under simulated solar illumination, EH-TNTAs-600 achieves the best photoconversion efficiency of up to 1.52% and maximum H2 generation rate of 40.4 ~mol h i cm-2, our- stripping other EH-TNTAs photoanodes. Systematic studies reveal that the signigicantly enhanced PEC performance for A-R mixed phaes EH-TNTAs-600 photoanode could be attributed to the synergy of A-R mixed phases and intentionally introduced Ti3~ （oxygen vacancies） which enhances the photoactivity over both UV and visible-light regions, and boosts both charge separation and transfer efficiencies. These findings provide new insight and guidelines for the construction of highly efficient TiO2-based devices for the application of solar water splitting.We first report that photoelectrochemical(PEC)performance of electrochemically hydrogenated TiO_2 nanotube arrays(TNTAs)as high-efficiency photoanodes for solar water splitting could be well tuned by designing and adjusting the phase structure and composition of TNTAs.Among various TNTAs annealed at different temperature ranging from 300 to 700°C,well-crystallized single anatase(A)phase TNTAs-400 photoanode shows the best photoresponse properties and PEC performance due to the favorable crystallinity,grain size and tubular structures.After electrochemical hydrogenation(EH),anataserutile(A-R)mixed phase EH-TNTAs-600 photoanode exhibits the highest photoactivity and PEC performance for solar water splitting.Under simulated solar illumination,EH-TNTAs-600 achieves the best photoconversion efficiency of up to 1.52% and maximum H_2 generation rate of 40.4 mmol h^(-1)cm^(-2),outstripping other EH-TNTAs photoanodes.Systematic studies reveal that the signigicantly enhanced PEC performance for A-R mixed phaes EH-TNTAs-600 photoanode could be attributed to the synergy of A-R mixed phases and intentionally introduced Ti^(3+)(oxygen vacancies)which enhances the photoactivity over both UV and visible-light regions,and boosts both charge separation and transfer efficiencies.These findings provide new insight and guidelines for the construction of highly efficient TiO_2-based devices for the application of solar water splitting.

关 键 词：TNTAs Electrochemical hydrogenation Phase Photoelectrochemistry Hydrogen generation 

分 类 号：O643.3[理学—物理化学]