Issue 39, 2022

Interfacial Bi–S bonds modulate band alignment for efficient solar water oxidation

Abstract

Introducing suitable interfacial chemical bonds into heterojunctions can increase the charge carrier density, propel the charge separation, and facilitate interfacial charge extraction in photoanodes for photoelectrochemical (PEC) water oxidation. However, tuning chemical bonds at heterojunction interfaces and elucidating their influences on band alignment and the associated evolution of PEC performance remain elusive. Herein, Bi–S bonds were introduced into the interface of a CdIn2S4 (CIS)/Bi2WO6 (BWO) heterojunction. In situ irradiated X-ray photoelectron spectroscopy and electron spin resonance signals confirm that the Bi–S bond transforms the band alignment from type II to the direct Z-scheme, significantly enhancing the carrier separation efficiency. Theoretical calculations show that the Bi–S bond not only acts as an atomic-level charge transfer channel, but also changes the migration pathway and distance within the heterojunction. As a result, the optimized CIS/BWO photoanode exhibits a relatively high PEC performance of 4.25 mA cm−2 at 1.23 V vs. RHE (VRHE) and a low onset potential of 0.30 VRHE. This work presents a new avenue to construct comprehensively improved photoanodes by tuning the interfacial structures at the atomic level.

Graphical abstract: Interfacial Bi–S bonds modulate band alignment for efficient solar water oxidation

Supplementary files

Article information

Article type
Paper
Submitted
15 Aug. 2022
Accepted
17 Sept. 2022
First published
19 Sept. 2022

Nanoscale, 2022,14, 14520-14528

Interfacial Bi–S bonds modulate band alignment for efficient solar water oxidation

W. Xu, N. Fan, S. Xu, L. Meng, B. Xu, M. Zhou, W. Tian and L. Li, Nanoscale, 2022, 14, 14520 DOI: 10.1039/D2NR04454D

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