Controllable fabrication of Cu:BiVO4 nanostructures via a two-step electrodeposition strategy for efficient photoelectrochemical water splitting

Abstract

A facile and reliable two-step electrodeposition method was successfully developed to construct and regulate copper incorporated BiVO₄ (Cu:BiVO₄) nanostructures with controllable surface morphologies and compositions for efficient photoelectrochemical water splitting. Cu:BiVO₄ nanofibers and nanonets were obtained after annealing the Cu nanoparticles electrodeposited BiOI nanosheets (Cu:BiOI) with the controlled radial immersion of vanadium precursor solution. The morphology and composition of Cu:BiVO₄ nanostructures can be effectively regulated by adjusting the concentration of Cu nanoparticles, which served as the heteroatom precursor and contributed to steric hindrance. A suitable doping concentration of Cu in Cu:BiVO₄ resulted in enhanced electronic conductivity and created nanostructures with large surface area and abundant catalytic active sites for improved charge transfer dynamics. As a result, photoelectrochemical properties of Cu:BiVO₄-150s photoanode with nanofibers and nanoparticles were improved significantly, realizing a 2.6-fold photocurrent density of 1.7 mA cm⁻² at 1.23 V vs. RHE compared to bare BiVO₄ under AM 1.5 G simulated solar irradiation. However, Cu:BiVO₄ nanonets with more interlaced nanostructure showed a decreased photocurrent density, which could be attributed to the introduction of more recombination centers. This simple yet general approach of morphology and composition control offers a beneficial guidance to develop doped semiconductors with controlled nanostructures for excellent water splitting performance.