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

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

doi:10.1016/j.scib.2017.12.023

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

Sci Bull (Beijing). 2018 Feb 15;63(3):194-202. doi: 10.1016/j.scib.2017.12.023. Epub 2017 Dec 24.

Authors

Jiaqin Liu¹, Mengjia Dai², Jian Wu², Ying Hu², Qi Zhang², Jiewu Cui³, Yan Wang³, Hark Hoe Tan⁴, Yucheng Wu⁵

Affiliations

¹ Institute of Industry and Equipment Technology, Hefei University of Technology, Hefei 230009, China; Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009, China; Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia. Electronic address: jqliu@hfut.edu.cn.
² Institute of Industry and Equipment Technology, Hefei University of Technology, Hefei 230009, China; Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009, China.
³ School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China; 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, ACT 2601, Australia.
⁵ School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China; Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009, China. Electronic address: ycwu@hfut.edu.cn.

PMID: 36659005
DOI: 10.1016/j.scib.2017.12.023

Abstract

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 °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), anatase-rutile (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 H₂ generation rate of 40.4 µmol 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 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.

Keywords: Electrochemical hydrogenation; Hydrogen generation; Phase; Photoelectrochemistry; TNTAs.