Supporting role of Galvanostatically deposited Bi nanoparticles as the substrate for photoelectrochemical application of Bi-W-oxide-based photoanode

초록

Tungsten-based metal oxide photoelectrodes are promising candidates for photoelectrochemical applications due to their cost-effective fabrication, high stability in electrolytic environments, low environmental impact, strong light absorption, and efficient charge transport through interconnected channels. In this study, a WO3/Bi2WO6 composite semiconductor was synthesized using an electrodeposited dendritic Bi-nanoparticle surface, onto which a tungsten precursor dissolved in ethylene glycol was drop-cast. The composite demonstrated a photocurrent density that was more than three times greater than that of pure WO3. This improvement in photoactivity is supported by various structural and compositional changes observed between the composite and the pure WO3 films. XRD analysis confirmed the presence of orthorhombic Bi2WO6 alongside monoclinic WO3 phase, with Bi2WO6 facilitating the growth of the more photoactive (002) plane of monoclinic WO3. EDX analysis of top-view and cross-sectional samples showed a higher atomic percentage of tungsten than bismuth, indicating thorough composite formation. The composite exhibited a minimum charge transfer resistance at the electrode-electrolyte interface compared to pure WO3, reflecting enhanced photoelectrochemical performance. The lower onset potential for photocurrent and a deeper conduction band position clearly demonstrate that the WO3/Bi2WO6 composite exhibits strong efficacy towards solar-driven water oxidation reactions.

키워드