Increasing the Efficiency of Photocatalytic Water Splitting via Introducing Intermediate Bands

Xinbo Ma; Wenjun Chu; Youxi Wang; Zhenyu Li; Jinlong Yang

doi:10.1021/acs.jpclett.2c03221

Increasing the Efficiency of Photocatalytic Water Splitting via Introducing Intermediate Bands

J Phys Chem Lett. 2023 Jan 26;14(3):779-784. doi: 10.1021/acs.jpclett.2c03221. Epub 2023 Jan 18.

Authors

Xinbo Ma¹, Wenjun Chu¹, Youxi Wang¹, Zhenyu Li¹, Jinlong Yang¹

Affiliation

¹ Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui230026, China.

PMID: 36652586
DOI: 10.1021/acs.jpclett.2c03221

Abstract

Photocatalytic water splitting is a potential way to utilize solar energy. To be practically useful, it is important to have a high solar-to-hydrogen (STH) efficiency. In this study, we propose a conceptually new photocatalytic water splitting model based on intermediate bands (IBs). In this new model, introducing IBs within the band gap can significantly increase the STH efficiency limit (from 30.7% to 48.1% without an overpotential and from 13.4% to 36.2% with overpotentials) compared to that in conventional single-band gap photocatalytic water splitting. First-principles calculations indicate that N-doped TiO₂, Bi-doped TiO₂, and P-doped ZnO have suitable IBs that can be used to construct IB photocatalytic water splitting systems. The STH efficiency limits of these three doped systems are 10.0%, 12.0%, and 19.0%, respectively, while those of pristine TiO₂ and ZnO without IB are only 0.9% and 1.6%, respectively. The IB photocatalytic water splitting model proposed in this study opens a new avenue for photocatalytic water splitting design.