BiVO4-modified anodic nanocoral WO3 structures for enhancement of photoelectrochemical performance

초록

Nanostructuring of metal oxides is a straightforward strategy for enhancing photoelectrochemical (PEC) performance. The present work demonstrates the anodization of W metal to determine the optimum WO3 nanostructure for use in photoanodes. Anodization was performed in a fluoride-containing 1 M Na2SO4 electrolyte. Under optimum conditions, WO3 nanocoral structures were fabricated. The forming mechanism of the nanocoral structures was elucidated by the generation and development of nanobubbles at the metal/oxide interface. To enhance the PEC performance, BiVO4 layers were coated on the anodic WO3 nanocoral structures and annealed at 500 degrees C in air atmosphere. The prepared BiVO4/WO3 nanocoral layers were characterized by SEM, XRD, EIS and UV-vis spectroscopy. They were then used as photoanodes for PEC and IPCE measurements. Consequently, photocurrent density was improved to 0.42 mA/cm(2) at 1.23 V vs. RHE and IPCE at 400 nm (21%) was enhanced by 21 times due to the producing band alignment between BiVO4 and WO3.

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