Issue 6, 2024

Z-scheme water splitting utilizing CuLi1/3Ti2/3O2 as a hydrogen-evolving photocatalyst with photo-response up to 600 nm

Abstract

CuLi1/3Ti2/3O2 (CLTO) is a visible-responsive photocatalyst, whose photo-response reaches up to 600 nm, for H2 evolution using sacrificial electron donors such as methanol and S2−. In this study, utilization of CLTO in Z-scheme water splitting (Z-WS) was investigated. The photocatalytic performance of Cr2O3/M/CLTO as a H2-evolving photocatalyst, which was prepared by sequential photodeposition of cocatalysts (M: Ru, Rh, Pd and Pt) and Cr2O3, was evaluated for Z-WS using BiVO4, an O2-evolving photocatalyst, and a Co(bpy)33+/2+ redox shuttle under visible light. Among the examined samples, Cr2O3/Ru/CLTO produced both H2 and O2 with meaningful rates. Thus, CLTO was first utilized in a visible responsive Z-scheme system for water splitting. The Cr2O3 layer played a significant role in the suppression of backward reactions, such as reduction of Co(bpy)33+. The activity of Cr2O3/Ru/CLTO for Z-WS was remarkably affected by the deposition conditions of the Ru cocatalyst. The activity for Z-WS was remarkably improved when the photodeposition of the Ru cocatalyst was conducted in a methanol solution of RuCl3. Unusually large plate Ru species with 100–200 nm sizes and about 30 nm thickness were present in the highly active sample. Characterization using X-ray photoelectron spectroscopy and X-ray absorption spectroscopy indicated that the Ru cocatalyst was deposited as mainly the oxyhydroxide of Ru. Z-WS also proceeded in the absence of Co(bpy)33+/2+ (the system based on interparticle electron transfer), however, the Z-scheme system using the Co(bpy)33+/2+ electron shuttle showed 10 times higher activity than the interparticle electron transfer system. The external quantum yield and efficiency of solar energy conversion to hydrogen were determined to be 0.5% at 430 nm and 0.029%, respectively.

Graphical abstract: Z-scheme water splitting utilizing CuLi1/3Ti2/3O2 as a hydrogen-evolving photocatalyst with photo-response up to 600 nm

Supplementary files

Article information

Article type
Paper
Submitted
13 12 2023
Accepted
05 2 2024
First published
05 2 2024
This article is Open Access
Creative Commons BY-NC license

Sustainable Energy Fuels, 2024,8, 1260-1268

Z-scheme water splitting utilizing CuLi1/3Ti2/3O2 as a hydrogen-evolving photocatalyst with photo-response up to 600 nm

S. Yoshino, T. Kurutach, Q. Liu, T. Yamanaka, S. Nozawa, M. Kobayashi, H. Kumagai and H. Kato, Sustainable Energy Fuels, 2024, 8, 1260 DOI: 10.1039/D3SE01622F

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