Coordinatively unsaturated atomically dispersed Pt+2-N4 sites on hexagonal nanosheet structure of g-C3N4 for high-performance photocatalytic H2 production

Developing active and stable metal single-atom catalysts is technically challenging. The electronic interactions between the metal site and its supports play a key role in altering electronic properties for the creation of more reactive and stable centers. The local environment of a single-atom catalyst directly affects its stability and reactivity. Herein, we describe the formation of coordinatively unsaturated atomically dispersed Pt+2 sites (Pt+2-N4) on hexagonal nanosheets of g-C3N4 (Pt1-HCN). This structure with Pt loading of 0.38 wt% exhibited a superb photocatalytic hydrogen evolution rate of 2900 µmol g−1 h−1 which was 5.6 times higher than that of the reactive Pt1 sites (Pt+4-N5) on bulk (Pt1-BCN). The comprehensive advance spectroscopic analysis combined with DFT calculations revealed that the strong electronic metal-support interactions between Pt1 and HCN effectively reduced the adsorbed Pt+4 sites into Pt+2 and create favorable uniform Pt+2-N4 moieties at low Pt loading for water adsorption, dissociation, and H2 evolution.