Construction of 2D-coal-based graphene/2D-bismuth vanadate compound for effective photocatalytic CO2 reduction to CH3OH

Abstract

Scalable and sustainable photocatalytic technology can convert CO2 to valuable hydrocarbons, which requires highly efficient and inexpensive photocatalyst with a broad light absorption range, high stability and fast carrier separation efficiency. Herein, a nanostructure with 2D/2D conformation consisting of BiVO4 and coal-based graphene oxide (CGO) were fabricated by hydrothermal method, which achieves efficient photoreduction of CO2 to CH3OH. Surprisingly, this nanostructure exhibits a significantly enhanced photocurrent density (0.95 mA/cm2), good CO2 adsorption capacity (1.34 cm3/gSTP) and medium stability. Moreover, the optimized 10-CGO/BiVO4 composite shows moderate CO2 conversion activity with a CH3OH production of 537.78 μmol/g h under light irradiation, which is approximately 6.47 times higher than that of BiVO4 nanosheets. The enhanced photocatalytic activity can be attributed to the following three points: broadened visible light absorption ability, unique ultra-thin structure and abundant surface active sites; effective photocarriers separation efficiency and reduced interfacial resistance at their heterojunction between BiVO4 and CGO nanosheets; CGO as co-catalyst with an electron-transfer path coupling with CGO can expedite the separation speed of carriers of photocatalyst, reduce the interface resistance and enrich surface active sites. This work provides inspiration for high performance binary photocatalyst in solar-chemical energy conversion process.