Constructed Z-Scheme g-C3N4/Ag3VO4/rGO Photocatalysts with Multi-interfacial Electron-Transfer Paths for High Photoreduction of CO2

Z-scheme g-C3N4/Ag3VO4/reduced graphene oxide (rGO) photocatalysts with multi-interfacial electron-transfer paths enhancing CO2 photoreduction under UV-vis light irradiation were successfully prepared by a hydrothermal process. Transmission electron microscope images displayed that the prepared photocatalysts have a unique 2D-0D-2D ternary sandwich structure. Photoelectrochemical characterizations including TPR, electrochemical impedance spectroscopy, photoluminescence, and linear sweep voltammetry explained that the multi-interfacial structure effectively improved the separation and transmission capabilities of photogenerated carriers. Electron spin resonance spectroscopy and band position analysis proved that the electron-transfer mode of g-C3N4/Ag3VO4 meets the Z-scheme mechanism. The introduction of rGO provided more electron-transfer paths for the photocatalysts and enhanced the stability of Ag-based semiconductors. In addition, the π-π conjugation effect between g-C3N4 and rGO further improved the generation and separation efficiency of photogenerated electron-hole pairs. Then, the multiple channels (Ag3VO4 → CN, Ag3VO4 → rGO → CN, and rGO → CN) due to the 2D-0D-2D structure greatly improving the photocatalytic CO2 reduction ability have been discussed in detail.