Single-step strategy for the fabrication of GaON/ZnO nanoarchitectured photoanode their experimental and computational photoelectrochemical water splitting

Electrode materials efficiency and stability are two indispensable bottlenecks in solar-driven water splitting which impedes its large-scale productions. Here, we report the novel fabrication of GaON/ZnO nanoarchitecture over FTO substrate, as a conceivable substitute for efficient solar-driven photoelectrochemical (PEC) water splitting. The synthesis of nitrogen enriched photoactive GaON/ZnO is accomplished by the single-step hydrothermal method. The formation of GaON /ZnO is observed in field emission scanning electronic micrographs (FE-SEM), which suggested that the ZnO hexagonal nanorods (NRs) bulging out from the nanosheets of GaON carving nanoarchitecture morphology. X-Ray Photoelectron Spectroscopy (XPS) reveals the formation of Ga-N and Ga-O bonds in GaON/ZnO. The Tauc's plot shows red wavelength shift from 390 to 460 nm corresponds to bandgap 3.26-2.58 eV for ZnO/GaON. The observed photocurrent densities for GaON, ZnO and GaON/ZnO are similar to 0.2, similar to 0.4 and similar to 1.2 mA/cm(2), which reveals significant 6- and 3-folds increase for GaON/ZnO compared to pristine GaON and ZnO, respectively. The density functional theory (DFT) calculations for a model system consisting of Zn3O3 cluster on (111) surface of GaON shows strong water molecules absorption with probable water splitting reaction. Loading GaON surface with Zn3O3 nanoparticle further enhances the dissociative adsorption energy of water molecules. The experimental and theoretical findings provided a rational enhancement of water splitting process in GaON/ZnO nanoarchitecture.