Construction of 2D all-solid-state Z-scheme g-C3N4/BiOI/RGO hybrid structure immobilized on Ni foam for CO2 reduction and pollutant degradation

In this work, a special hybrid structure with 2D configuration comprising of g-C3N4, reduced graphene oxide (RGO), and BiOI (g-C3N4/BiOI/RGO) was rationally constructed and immobilized on Ni foam with RGO functioned as electron transfer mediator and binder. The immobilized 2D g-C3N4/BiOI/RGO hybrid structure exhibited the enhanced photocatalytic CO2 reduction to CO and the methyl orange (MO) degradation efficiency under visible light irradiation. Particularly, the hybrid heterojunction with a mass ratio 6% of BiOI to g-C3N4 displayed the highest CO yield and degradation rate constant for MO, which was 1.6 times and 3 times of g-C3N4/RGO binary heterojunction immobilized on Ni foam. The enhanced photocatalytic activity was ascribed to the rapid charge separation. More importantly, combined with the theoretical calculations on the work functions of g-C3N4, rGO and BiOI, the experimental results clarified the charges transfer route of g-C3N4/BiOI/RGO heterojunction conforming to the Z-scheme mechanism.