Valence Band Engineering via PtII Single-Atom Confinement Realizing Photocatalytic Water Splitting

Direct water splitting in pure water relying on photocatalysis is an effective way to realize an efficient solar to chemical fuel conversion toward solving the global energy crisis and environmental problems. Here, via a “high-valence metal single-atom confinement” strategy, we effectively modify the valence band structure of the semiconductor photocatalyst toward a spontaneous photocatalytic water splitting in pure water. This as-prepared PtII–C3N4 could achieve an efficient photocatalytic water splitting activity with the H2 production rate up to ∼140 μmol g–1 h–1, about 10 times that of Pt nanoparticle–C3N4 (15 μmol g–1 h–1). Moreover, the unique PtII–C3N4 suspension in pure water exhibits an impressive quantum efficiency of 1.5% at 420 nm under visible light irradiation. Electronic structure characterizations and theoretical calculations reveal that the hybridization of PtII 5d and N 2p obviously downward shifts the valence band maximum level of PtII–C3N4 by 0.26 V relative to g-C3N4, which could significantly promote the reaction thermodynamics of oxygen evolution toward the high photocatalytic water splitting activity.