Z-scheme Photocatalytic CO2 Conversion on Three-Dimensional BiVO4/Carbon-Coated Cu2O Nanowire Arrays under Visible Light

Abstract

Cuprous oxide (Cu2O) is one of the most promising materials for photoreduction of CO2 because of its high conduction band and small band gap, which enable the production of high-potential electrons under visible-light irradiation. However, it is difficult to reduce the CO2 using a Cu2O-based photocatalyst due to fast charge recombination and low photostability. In this work, we enhanced the photocatalytic CO2 conversion activity of Cu2O by hybridization of Cu2O NWAs, carbon layers, and BiVO4 nanoparticles. By construction of a Z-scheme charge flow on a 3-D NWA structure, the BiVO4/carboncoated Cu2O (BVO/C/Cu2O) NWAs show significantly enhanced charge separation and light harvesting property. As a result, CO formation rate of BVO/C/Cu2O was 9.4 and 4.7 times those of Cu2O mesh and Cu2O NWAs, respectively, under visible light irradiation. In addition, the material retained 98% of its initial photocatalytic CO2 conversion performance after five reaction cycles (20 h) because of the protective carbon layer and Z-schematic charge flow. We believe that this work provides a promising photocatalyst system that combines a 3-D NWA structure and a Z-scheme charge flow for efficient and stable CO2 conversion.