Defective high-entropy oxide photocatalyst with high activity for CO2 conversion

TL;DR

This study demonstrates that a defective high-entropy oxide (HEO) photocatalyst exhibits superior activity for converting CO2 into useful chemicals, outperforming traditional catalysts due to its structural defects and strain.

Contribution

The paper introduces a novel defective HEO photocatalyst synthesized via high-pressure torsion, showing enhanced CO2 conversion without co-catalysts, highlighting its potential as a new photocatalytic material.

Findings

HEO shows high photocatalytic activity for CO2 to CO and H2O to H2 conversion.

HEO outperforms conventional photocatalysts like anatase TiO2 and BiVO4.

The activity is linked to structural defects, lattice strain, and charge mobility.

Abstract

High-entropy oxides (HEOs), as a new family of materials with five or more principal cations, have shown promising properties for various applications. In this work and inspired by inherent defective and strained structure of HEOs, photocatalytic CO2 conversion is examined on a dual-phase TiZrNbHfTaO11 synthesized by a two-step high-pressure torsion mechanical alloying and high-temperature oxidation. The HEO, which had various structural defects, showed simultaneous photocatalytic activity for CO2 to CO and H2O to H2 conversion without the addition of a co-catalyst. The photocatalytic activity of this HEO for CO2 conversion was better than conventional photocatalysts such as anatase TiO2 and BiVO4 and similar to P25 TiO2. The high activity of HEO was discussed in terms of lattice defects, lattice strain, light absorbance, band structure, photocurrent generation and charge carrier mobility to activation centers. The current study confirms the high potential of HEOs as a new family of photocatalysts for CO2 conversion.