Local spatial polarization induced efficient electron transfer in fluorinated borocarbonitride for boosting CO2 photoreduction

CO2 photoreduction into highly value-added chemicals over metal-free h-BCN has emerged as a promising strategy to address the issue of global warming. However, the serious carrier recombination caused by disordered charger transfer has limited its practical application. To circumvent this issue, fluorine modified h-BCN were synthesized using a facile heat treatment method. The surface halogenation created local spatial polarized electric field, which facilitated the local charge separation and transmission efficiency. Among them, BCN-F-4 exhibited the best photocatalytic CO2 reduction activitiy with CO and CH4 yield of 25.38 and 14.11 µmol g−1h−1, respectively. The turnover number (TON) of BCN-F-4 reached up to 163.6 μmol g−1h−1, 4.4 times that of BCN. Both theoretical simulation and experimental analysis demonstrated a strong covalent interaction between the F atoms and the h-BCN matrix, which gain deep understanding of the mechanism of prominent photocatalytic CO2 reduction activity boosted by surface halogenation.