In-situ growth of Z-Scheme Ag/PPy/BiVO4 core–shell structure for efficient CO2 photoreduction into hydrocarbon fuels

Photocatalytic reduction of CO2 to hydrocarbons (e.g., CH4) or CO under mild conditions, providing a feasible and promising method for the environmental remediation and utilization of carbon resources. However, since CO2-to-CO is a two–electron process, and even CO2-to-CH4 is an eight-electron reaction, it is a challenging task to achieve CO2 activation with an extremely short effective charge lifetime. In this paper, a synergistic effect strategy is used to prepare Ag nanoparticles modified PPy/BiVO4 Z-Scheme composites for synergizing the charge separation and surface catalytic processes in CO2 reduction reaction. With the joint efforts of synergy, the optimal photocatalyst achieves an efficient CO2 reduction yield (5.92 μmol·g−1·h−1) with an exceptionally high CO selectivity of 85.8% and the corresponding O2 evolution. Based on the result analysis, it can be clearly proved that the excellent CO2 reduction performance relies on the Z–Scheme charge transfer mechanism between PPy/BiVO4 composites interface and the strong catalytic effect of Ag nanoparticles on CO2. Furthermore, the detailed processes of deoxygenation and proton acquisition during CO2 reduction is revealed by in-situ DRIFTS and NAP-XPS. This paper demonstrates a strategy for designing efficient photocatalysts toward reduction of CO2 to higher value-added chemicals, and highlights the importance of catalysis and charge separation to the synergy of key steps in catalytic reactions.