Architecture modification and In^(3+)-doping of WO_(3) photoanodes to boost the photoelectrochemical water oxidation performance

WO_(3) photoanodes have been widely utilized for the oxygen evolution reaction(OER)in the photoelectrochemical water splitting system.Herein,the effects of hydrazine hydrate modification and In^(3+)-doping on the physicochemical properties and photocurrent density of the WO_(3) photoanode prepared by hydrothermally treating at 160℃followed by calcining at 500℃are investigated.Among them,the hydrazine hydrate in the hydrothermal solution can serve as a texture regulator,resulting in the formation of WO_(3) films with the layered architecture stacked by nanosheets dominantly exposed(020)facets,which allows the WO_(3) films to have faster charge separation and larger specific surface area for OER according to the characterization results of microstructures and photoelectrochemcial behaviors;while the In^(3+)-doping can optimize the energy band structure of WO_(3) and adjust the work function to increase the driving force of OER based on the ultraviolet photoelectron spectroscopy,Mott–Schottky and open-circuit photovoltage plots.Under the simulated sunlight(AM1.5G)illumination,the designed In^(3+)–WO_(3)(N_2H_4)photoanode in Na_2SO_4 solution delivers amaximum incident photon-to-current efficiency of 38.6%at 410 nm and a photocurrent density of 1.93 mA cm^(-2)at 1.23 V vs.RHE,which is 2.8 and 3.0 times higher than the pristine WO_(3) photoanode,respectively.This study provides a promising strategy to improve the water splitting performance of nanostructured WO_(3) photoanodes by altering the architecture and introducing heteroatoms.