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

Shunya Yoshino; Tanya Kurutach; Qingshan Liu; Toshiki Yamanaka; Shunsuke Nozawa; Makoto Kobayashi; Hiromu Kumagai; Hideki Kato

doi:10.1039/D3SE01622F

Z-scheme water splitting utilizing CuLi_1/3Ti_2/3O₂ as a hydrogen-evolving photocatalyst with photo-response up to 600 nm†

Shunya Yoshino,^a Tanya Kurutach,^ab Qingshan Liu,^ab Toshiki Yamanaka,^ab Shunsuke Nozawa,^c Makoto Kobayashi,

^d Hiromu Kumagai

^e and Hideki Kato

*^a

Author affiliations

* Corresponding authors

^a Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
E-mail: hideki.kato.e2@tohoku.ac.jp

^b Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan

^c Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan

^d Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan

^e Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan

Abstract

CuLi_1/3Ti_2/3O₂ (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)₃^3+/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)₃^3+/2+ (the system based on interparticle electron transfer), however, the Z-scheme system using the Co(bpy)₃^3+/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.

This article is part of the themed collections: Recent Open Access Articles and Solar Fuels and Chemicals: Photocatalytic Water Splitting and CO2 Reduction

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Article information

DOI: https://doi.org/10.1039/D3SE01622F
Article type: Paper
Submitted: 13 Dec 2023
Accepted: 05 Feb 2024
First published: 05 Feb 2024
This article is Open Access

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Sustainable Energy Fuels, 2024,8, 1260-1268

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Z-scheme water splitting utilizing CuLi_1/3Ti_2/3O₂ 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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