NiCo2O4 nanosheets as a novel oxygen-evolution-reaction cocatalyst in situ bonded on the g-C3N4 photocatalyst for excellent overall water splitting

A 2D/2D coupled NiCo2O4/g-C3N4 nanostructure was fabricated through an in situ growth strategy. NiCo2O4 worked as a novel oxygen-evolution-reaction cocatalyst, and the intimate interface combination by surface bonding and the related cooperative effect between NiCo2O4 and g-C3N4 were comprehensively explored. Consequently, the separation and migration of photo-generated charge carriers for g-C3N4 were efficiently promoted, as well as the energy barriers of the oxygen evolution reaction were reduced. NiCo2O4/g-C3N4 showed obviously enhanced photocatalytic O2-evolution activity (4.6 times that of bare g-C3N4), and the corresponding AQY achieved 4.9% at 380 nm. Then, Pt as a hydrogen-evolution-reaction cocatalyst was employed to cooperate with NiCo2O4 to construct dual cocatalyst loaded g-C3N4 for photocatalytic overall water splitting, in which H2 and O2 simultaneously evolved in a stoichiometric ratio of 2 : 1, and the AQY for H2 evolution reached 2.8% at 380 nm. Consequently, this work demonstrates a reliable strategy for g-C3N4 to construct a photocatalytic system for efficient overall water splitting.