Nanostructured Tungsten Trioxide Thin Films Synthesized for Photoelectrocatalytic Water Oxidation: A review

The recent developments of nanostructured WO3 thin films synthesized through the electrochemical route of electrochemical anodization and cathodic electrodeposition for the application in photoelectrochemical (PEC) water splitting are reviewed. The key fundamental reaction mechanisms of electrochemical anodization and cathodic electrodeposition methods for synthesizing nanostructured WO3 thin films are explained. In addition, the effects of metal oxide precursors, electrode substrates, applied potentials and current densities, and annealing temperatures on size, composition, and thickness of the electrochemically synthesized nanostructured WO3 thin films are elucidated in detail. Finally, a summary is given for the general evaluation practices used to calculate the energy conversion efficiency of nanostructured WO3 thin films and a recommendation is provided to standardize the presentation of research results in the field to allow for easy comparison of reported PEC efficiencies in the near future. It′s all a matter of e: The synthesis of nanostructured WO3 to be used for photochemical water splitting using various electrochemical routes is reviewed. Key fundamental reaction mechanisms and various effects of synthesis methods and approaches on physical, chemical, optical, and photoelectrochemical properties of nanostructured WO3 are explained. Also, a summary of the current evaluation practices on the energy conversion efficiency of nanostructured WO3 is provided.