Organic half-metal derived erythroid-like BiVO4/hm-C4N3 Z-Scheme photocatalyst: Reduction sites upgrading and rate-determining step modulation for overall CO2 and H2O conversion

Photocatalytic overall CO2 and H2O conversion has been very challenging. Herein, a hierarchical erythroid-like BiVO4/hm-C4N3 direct Z-Scheme heterojunction is developed through elaborate template inducement and in-situ polymerization. The superior CO2 capture, activation and charge deliver features are all integrated in reduction site of the Z-Scheme system. The overall photocatalytic CO2 and H2O conversion to CO and O2 are achieved without any sacrificial reagent and co-catalyst. In particular, the optimized BiVO4/hm-C4N3 presents a CO production rate of 40.8 mu mol g-1 h-1 with a selectivity beyond 97 %. DFT calculation and in-situ DRIFTS spectra indicate that the dehydration of *COOH to CO is the rate-determining step. The supplement of proton by H2O oxidation from BiVO4 and the prolonged lifetime of electrons simultaneously contribute to the remarkable decreased reaction barrier. This work provides a new strategy to develop organic half-metal based photocatalyst, and may pave a new way to the target of artificial photosynthesis.

Automated summary

The study developed a hierarchical erythroid-like BiVO4/hm-C4N3 direct Z-Scheme heterojunction, achieving overall photocatalytic CO2 and H2O conversion to CO and O2 without any sacrificial reagent and co-catalyst. The optimized catalyst demonstrated high CO production rate and selectivity.