Efficient Electron Transfer in g-C3N4/TiO2 Heterojunction for Enhanced Photocatalytic CO2 Reduction

Abstract

Excessive emissions of carbon dioxide have led to the greenhouse effect and global warming. Reducing carbon dioxide into high-value-added chemicals through solar energy is a promising approach. Herein, a g-C3N4/TiO2 heterojunction photocatalyst with efficient electron transfer is designed for photocatalytic CO2 reduction. The CH4 (18.32 µmol·h−1·g−1) and CO (25.35 µmol·h−1·g−1) evolution rates of g-C3N4/TiO2 are higher than those of g-C3N4 and TiO2. The enhanced photocatalytic CO2 reduction performance is attributed to the efficient charge carrier transfer in the g-C3N4/TiO2 heterojunction. The electron transfer route was verified by in situ irradiated X-ray photoelectron spectroscopy (XPS). The photocatalytic CO2 reduction mechanism on g-C3N4/TiO2 was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). This work provides a strategy for designing a polymer/metallic oxide heterojunction with efficient electron transfer for enhanced photocatalytic CO2 reduction.