Enhanced visible/near-infrared light harvesting and superior charge separation via 0D/2D all-carbon hybrid architecture for photocatalytic oxygen evolution

Abstract

Since the water splitting rate-limiting oxygen evolution remains sluggish, engineering a rational architecture for photocatalysts to fulfill water oxidation needs becomes a vital issue. Here, we detail a 0D/2D all-carbon hybrid strategy for constructing a heterostructure of carbon dots (CDots) and reduced graphene oxide (rGO) to enhance the photocatalytic water oxidation of monoclinic-BiVO4 nanosheets (CBrG). Given the visible-light-harvesting ability and up-conversion characteristics of 0D CDots, more photogenerated electron-hole pairs participated in water oxidation under visible and near-infrared light irradiation. Meanwhile, 0D CDots behaved as electron acceptors on 2D rGO to suppress the recombination of electron-hole pairs. This nature licenses for the feasible electron transfer from excited m-BiVO4 to 0D CDots via electron transfer channels of 2D rGO, facilitating the separated holes to migrate onto the m-BiVO4 surface for water oxidation. Compared with the rGO decorated m-BiVO4 nanosheets (BrG), these merits endow the CBrG with an over 212% enhancement in O2 yield under visible light irradiation as well as notable O2 yield under near-infrared light irradiation, and a 1.57-fold increase in apparent quantum efficiency. The enhancement is also verified by the significant growth of ·OH radicals derived from OH−/H2O oxidation and ·OOH/·O2− radicals originated from O2 reduction. This work paves a new way for the 0D/2D all-carbon hybrid architecture applied in solar energy conversion.