Efficient Photoelectrochemical Water Oxidation over Cobalt-Phosphate (Co-Pi) Catalyst Modified BiVO4/1D-WO3 Heterojunction Electrodes

We report the design, synthesis and photoelectrochemical characterization of cobalt phosphate (Co-Pi) oxygen evolution catalyst modified heterojunction photoelectrodes consisting of one-dimensional WO₃ nanorods (1D-WO₃) and highly porous BiVO₄ layers. The 1D-WO ₃ nanorods were prepared by the decomposition of the tetrabutylammonium decatungstate precursor in the presence of poly(ethylene glycol) as a binding agent. The porous BiVO₄ layers were spray deposited using a surfactant assisted metal-organic decomposition method. The Co-Pi oxygen evolution catalyst was deposited onto the BiVO₄/1D- WO₃/FTO heterojunction electrode using a photoassisted electrodeposition method. The Co-Pi catalyst modified heterojunction electrodes exhibited a sustained enhancement in the photocurrent compared to the unmodified BiVO₄/1D-WO₃/FTO heterojunction electrodes. The improved photoelectrochemical properties profited from the enhanced charge carrier separation achieved through the integration of highly porous BiVO₄ layers on top of 1D-WO₃ nanorods and from the superior kinetics due to the presence of the Co-Pi oxygen evolution catalyst on top of BiVO ₄/1D-WO₃/FTO heterojunction electrodes. This journal is