Efficient photocatalytic overall water splitting over a core-shell GaInZnON@GaInON homojunction

[Display omitted] •A core-shell p-type GIZON homojunction photocatalyst is prepared.•The homojunction shows an ideal type-I band alignment.•An intermediate band nearby the Fermi level of the shell promotes charge transfer.•Photocatalytic overall water splitting with an AQY of 3.5% is achieved. Direct overall water splitting via photocatalysis provides a potential pathway for solar energy conversion. The essential section is to develop efficient and stable photocatalysts, yet with limited success to date. Here a novel p-type gallium indium zinc oxynitride homojunction photocatalyst with core-shell structure is reported, which exhibits H2 and O2 evolution rates of 603 and 274 μmol h−1 g−1 with an apparent quantum efficiency of 3.5% at 430 nm from overall pure water splitting. Precise characterizations and DFT calculations reveal that the excellent photocatalytic performance is ascribed to the facilitated charge transfer contributed by the ideal type-I band alignment between GaInZnON core and GaInON shell, combined with the intermediate level formed nearby the Fermi level of GaInON shell. Our work offers insight into the development of facile synthesis of core-shell structure photocatalysts towards efficient solar-driven overall water splitting.