Criteria for Efficient Photocatalytic Water Splitting Revealed by Studying Carrier Dynamics in a Model Al-doped SrTiO3 Photocatalyst

Ronghua Li; Tsuyoshi Takata; Beibei Zhang; Chao Feng; Qianbao Wu; Chunhua Cui; Zemin Zhang; Kazunari Domen; Yanbo Li

doi:10.1002/anie.202313537

Criteria for Efficient Photocatalytic Water Splitting Revealed by Studying Carrier Dynamics in a Model Al-doped SrTiO₃ Photocatalyst

Angew Chem Int Ed Engl. 2023 Dec 4;62(49):e202313537. doi: 10.1002/anie.202313537. Epub 2023 Nov 3.

Authors

Ronghua Li¹, Tsuyoshi Takata², Beibei Zhang¹, Chao Feng¹, Qianbao Wu¹, Chunhua Cui¹, Zemin Zhang³, Kazunari Domen^{2

4}, Yanbo Li¹

Affiliations

¹ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China.
² Research Initiative for Supra-Materials (RISM), Shinshu University, Nagano, 380-8553, Japan.
³ School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China.
⁴ Office of University Professors, The University of Tokyo, Tokyo, 113-8656, Japan.

PMID: 37857989
DOI: 10.1002/anie.202313537

Abstract

Overall water splitting (OWS) using semiconductor photocatalysts is a promising method for solar fuel production. Achieving a high quantum efficiency is one of the most important prerequisites for photocatalysts to realize high solar-to-fuel efficiency. In a recent study (Nature 2020, 58, 411-414), a quantum efficiency of almost 100 % has been achieved in an aluminum-doped strontium titanate (SrTiO₃ : Al) photocatalyst. Herein, using the SrTiO₃ : Al as a model photocatalyst, we reveal the criteria for efficient photocatalytic water splitting by investigating the carrier dynamics through a comprehensive photoluminescence study. It is found that the Al doping suppresses the generation of Ti³⁺ recombination centers in SrTiO₃ , the surface band bending facilitates charge separation, and the in situ photo-deposited Rh/Cr₂ O₃ and CoOOH co-catalysts render efficient charge extraction. By suppressing photocarrier recombination and establishing a facile charge separation and extraction mechanism, high quantum efficiency can be achieved even on photocatalysts with a very short (sub-ns) intrinsic photocarrier lifetime, challenging the belief that a long carrier lifetime is a fundamental requirement. Our findings could provide guidance on the design of OWS photocatalysts toward more efficient solar-to-fuel conversion.

Keywords: Carrier Dynamics; Overall Water Splitting; Photoluminescence; SrTiO3 Photocatalyst.

Abstract

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