Reducing the surface defects of Ta3N5 photoanode towards enhanced photoelectrochemical water oxidation

Chenyi Shao; Ruotian Chen; Yongle Zhao; Zheng Li; Xu Zong; Can Li

doi:10.1039/D0TA08121C

Reducing the surface defects of Ta₃N₅ photoanode towards enhanced photoelectrochemical water oxidation†

Chenyi Shao,^ab Ruotian Chen,^a Yongle Zhao,^ab Zheng Li,^a Xu Zong

*^a and Can Li

*^a

Author affiliations

* Corresponding authors

^a State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, The Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Zhongshan Road 457, Dalian 116023, P. R. China
E-mail: xzong@dicp.ac.cn, canli@dicp.ac.cn

^b University of Chinese Academy of Sciences, Beijing 100049, P. R. China

Abstract

Tuning the concentration and location of defects in semiconductors has been found to be effective in modifying their photoelectrochemical (PEC) performance. Herein, we present the fabrication of Ta₃N₅ photoanodes with reduced surface defects through the nitridation of a two-step-flame-heating-derived Ta₂O₅ precursor (TSFH-Ta₂O₅). We found that by using TSFH-Ta₂O₅ instead of the one-step-flame-heating-derived Ta₂O₅ (OSFH-Ta₂O₅), the concentrations of low valence Ta species on the surface of Ta₂O₅ and the resulting Ta₃N₅ photoelectrodes are reduced. Moreover, we clarified that low valence Ta species on the Ta₃N₅ surface led to the formation of undesirable surface states, which induces severe Fermi level pinning and aggravates charge recombination. Therefore, TSFH-Ta₃N₅ delivered enhanced charge separation and injection efficiencies for PEC water oxidation reaction. A photocurrent density of 6.8 mA cm⁻² at 1.23 V vs. reversible hydrogen electrode (RHE) was obtained on TSFH-Ta₃N₅ after loading a Co(OH)_x cocatalyst, which is among the highest values reported for planar Ta₃N₅ photoanodes.

This article is part of the themed collection: Journal of Materials Chemistry A HOT Papers

Supplementary files

Article information

DOI: https://doi.org/10.1039/D0TA08121C
Article type: Paper
Submitted: 18 Aug 2020
Accepted: 14 Sep 2020
First published: 22 Oct 2020

Download Citation

J. Mater. Chem. A, 2020,8, 23274-23283

Permissions

Request permissions

Reducing the surface defects of Ta₃N₅ photoanode towards enhanced photoelectrochemical water oxidation

C. Shao, R. Chen, Y. Zhao, Z. Li, X. Zong and C. Li, J. Mater. Chem. A, 2020, 8, 23274 DOI: 10.1039/D0TA08121C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Journal of Materials Chemistry A