Z-scheme π-π stacking MXene/GO/PDI composite aerogels to construct interface electron transport network for photocatalytic CO2 reduction

Converting artificial photosynthesis into value-added chemicals through photocatalytic CO2 reduction reaction (CO2RR) is a sustainable and economical strategy to solve energy and environmental problems. Here, a series of new three-dimensional (3D) MXene/GO/perylene diimide (PDI) composite aerogels were prepared, and an electron transfer network in a π-π stacking form was constructed through self-assembly. The methyl formate (MF) generation rate of the optimized MXene/GO/PDI composite aerogel for photocatalytic CO2RR in methanol is 771.1 μmol g−1 h−1, about 8 fold that of the pure MXene/PDI composite catalyst. The substantially improved performance is attributed to the strong coupling heterogeneous interface established by π-π stacked cross-linking network and the Z-scheme heterojunction constructed between MXene/GO aerogel and PDI. Thus, the transmission of photogenerated electrons is accelerated to improve the oxidation-reduction ability at the interface. A tentative mechanism for selective photocatalysis of methanol to MF over MXene/GO/PDI composite aerogels was put forward. This work provides an efficient strategy to prepare non-precious heterostructure photocatalysts for MF production and other related reactions.