Phosphatized GaZnInON nanocrystals with core-shell structures for efficient and stable pure water splitting via four-electron photocatalysis

Abstract

Overall water splitting via solar-driven photocatalysis provides an ideal way to realizing a viable and sustainable hydrogen economy, while the development of efficient photocatalysts remains a grand challenge to date. Herein, we report the successful surface phosphorization of a gallium indium zinc oxynitride (GaInZnON) photocatalyst, which comprises a GaInZnON core and a thin InP shell. The success to the synthesis relies on the rapid diffusion of In from the bulk to the crystal surface and preferential combination of In with P to form an outer layer. The enhanced charge migration was confirmed with characterization and the charge redistribution difference around the heterojunction. The core-shell composite having an ideal type-II band alignment enables efficient charge separation within the particle scale and significantly improved photocatalytic activity toward pure water splitting for simultaneous and stoichiometric H2 and O2 evolution. The apparent quantum efficiencies can be up to 10.6% at 430 nm and 13.8% at 350 nm, respectively. Our results suggest that such core-shell GaInZnON@InP architectures hold great potential for efficient and scalable solar hydrogen generation.