Visible-light photocatalytic oxygen production on a high-entropy oxide by multiple-heterojunction introduction

TL;DR

This study demonstrates that high-entropy oxides with multiple heterojunctions can effectively produce oxygen from water under visible light, offering a new strategy for visible-light photocatalysis.

Contribution

The paper introduces a novel approach of incorporating multiple heterojunctions into high-entropy oxides to enable visible-light-driven photocatalytic oxygen production.

Findings

Successful synthesis of Ti-Zr-Nb-Ta-W-O high-entropy oxide with multiple heterojunctions.

Achieved visible-light-driven oxygen evolution without co-catalysts.

High photocatalytic activity attributed to broad visible-light absorption and efficient charge separation.

Abstract

High-entropy oxides (HEOs), as multi-component ceramics with high configurational entropy, have been of recent interest due to their attractive properties including photocatalytic activity for H2 production and CO2 conversion. However, the photocatalytic activity of HEOs is still limited to ultraviolet light. In this study, to achieve visible-light-driven photocatalysis, 10 different heterojunctions were simultaneously introduced in the Ti-Zr-Nb-Ta-W-O system. The oxide, which was synthesized by a high-pressure torsion method and oxidation, successfully produced oxygen from water under visible light without co-catalyst addition. The photocatalytic performance was attributed to high visible-light absorption, narrow bandgap, appropriate band structure, presence of multiple heterojunctions and accordingly easy electron-hole separation and slow recombination. These results not only show the potential of high-entropy oxides as new visible-light-active photocatalysts, but also introduce the multiple-heterojunction introduction as a strategy to achieve photocatalysis under visible light.