Research progress over Cu2O/n-type semiconductor composites in photocatalysis

Abstract

Photocatalysis is a feasible technology to solve energy shortage and environmental pollution by using solar energy. Semiconductor photocatalysts with low cost, high stability and environmental friendliness are demonstrated advantages for the production of solar fuel, CO2 reduction, and degradation of pollutants. Among them, Cu2O presents numerous potential for photocatalysis because of its narrow bandgap and high activity under visible light. However, the rapid recombination of photoinduced electron-hole pairs and the instability of Cu2O under light irradiation limit its photocatalytic performance. In order to solve the above issues, researchers prefer to incorporate Cu2O with n-type semiconductors to design p-n heterojunction composites, thus regulating the band structure, promoting the separation and transfer of electrons and holes, and accelerating the redox reaction onto the surface. In this manuscript, the preparation methods of Cu2O/n-type semiconductor composites such as hydrothermal method, electrodeposition method, and in situ method are concluded, the photocatalytic applications including CO2 reduction, hydrogen production, and degradation are presented, and the catalytic mechanism like Z-scheme, p-n heterojunction, etc. are discussed, respectively. This review also proposes that there are still challenges in broadening the photocatalytic application of Cu2O/n-type semiconductor composites.