Plasmonic gold nanoparticle-decorated BiVO₄/ZnO nanowire heterostructure photoanodes for efficient water oxidation

To enhance the charge separation and kinetics of water oxidation using a BiVO₄ photoanode, a BiVO₄/ZnO nanowire heterostructure decorated with gold (Au) nanoparticles is fabricated as a photoanode for photoelectrochemical water splitting. The Au/BiVO₄/ZnO nanowire photoanode exhibits improved photoactivity performance and visible light absorption due to its optimized nanowire length and loading of Au nanoparticles. The harvesting of visible light and charge separation are enhanced by the heterostructure with ZnO nanowires, providing a direct pathway for photogenerated electrons and inducing a morphological scattering effect. In addition, the kinetics of oxygen evolution and photoactivity are improved due to the localized surface plasmon resonances (LSPRs) and hot electron injection with Au nanoparticle oscillation. As a result, the photocurrent density of the Au/BiVO₄/ZnO nanowire photoanode is 4.5 times higher than that of the pristine BiVO₄ photoanode. The combination of the heterostructure and effective decoration of Au nanoparticles enables the expansion of the absorption region and increased photoactivity of the electrode for water oxidation.