光をつかった水素製造に酸化鉄を利用 ―チタンドープによる光触媒活性のメカニズムを解明―

2026-08-24 東北大学

図1. チタンドーピング量を変えた酸化鉄とロジウムドープチタン酸ストロンチウムを組み合わせたZスキーム型光触媒の水分解に対する活性

＜関連情報＞

• https://www.tohoku.ac.jp/japanese/2026/08/press20260824-01-Fe2O3.html
• https://pubs.acs.org/aaemcq/article/9/16/10519/5250124/Z-Scheme-Water-Splitting-Utilizing-Fe2O3-as-an

Fe2O3を酸素発生光触媒として利用したZスキーム型水分解 Z-Scheme Water Splitting Utilizing Fe2O3 as an Oxygen-Evolving Photocatalyst

Tomoomi Miyashita;Shunya Yoshino;Makoto Kobayashi;Hideki Kato
ACS Applied Energy Materials  Published:August 07, 2026
DOI:https://doi.org/10.1021/acsaem.6c01486

Abstract

Fe₂O₃ is a widely studied material as a photoanode and O₂ evolution photocatalyst responsive to visible light. Although Z-scheme systems employing Fe₂O₃-based photocatalysts have been reported, the kind of combined H₂-evolving photocatalyst is limited to C₃N₄. In this study, we demonstrated water splitting by the Z-scheme systems utilizing Ti-doped Fe₂O₃ (Fe₂O₃:Ti) and Rh-doped SrTiO₃ (SrTiO₃:Rh). Z-scheme water splitting (Z-WS) was achieved by the interparticle electron transfer from Fe₂O₃:Ti to SrTiO₃:Rh. Ti doping was essential to achieve Z-WS. Doping Ti into Fe₂O₃ increased the carrier density, causing improvement of electronic conductivity and enhancement of charge separation through band bending. These factors remarkably improved the photoelectrochemical property, resulting in achievement of Z-WS. The Ru/SrTiO₃:Rh-Fe₂O₃:Ti system was active for water splitting even without cocatalyst modification of Fe₂O₃:Ti. The activity was improved by the IrO_x deposition, while modification with MnO_x, FeO_x, CoO_x, and RhO_x decreased activity. The impregnation method involving heat treatment at 500–600 °C and the adsorption method followed by heat treatment at 500 °C were found to be an appropriate condition for IrO_x deposition through systematic characterization. The external quantum yield of the present system was determined to be 0.23% at 430 nm.