Enhanced photoelectrochemical hydrogen production via linked BiVO₄ nanoparticles on anodic WO₃ nanocoral structures

Morphological properties of photoanodes are crucial for improving their photoelectrochemical (PEC) performance. In this study, we fabricated bismuth vanadate (BiVO₄) nanoparticles (NPs) with an optimal size of ∼10 nm, as well as nanowires composed of NPs on anodized tungsten trioxide (WO₃) nanocoral structures. The linked BiVO₄ NPs were decorated by spin-coating, with the amount of the BiVO₄ precursor being controlled. Subsequently, the concentrations of Bi and V in the BiVO₄ precursor were determined. An optimized concentration of 0.3 M Bi and V for the linked BiVO₄ NPs/WO₃ nanocoral heterostructure led to enhanced photocurrent density and hydrogen gas-production compared to those of the pristine WO₃ nanocorals, yielding results that were 2.4 times higher. In particular, the incident photon-to-current conversion efficiency value at 410 nm improved by 8.3 times, as the linked BiVO₄ NPs attained efficient absorbance of visible light and a sufficient electron transfer pathway.