Aerosol-Deposited BiVO4 Photoelectrodes for Hydrogen Generation

Hydrogen generation from renewable energy sources will play a key role in the concerted endeavor to constrain climate change. One environmentally friendly route, powered by sunlight, is the photoelectrochemical water splitting cell (PEC). This technology employs electrodes coated with thin films of semiconductor materials to capture light and generate charge carriers that directly drive the water splitting reaction. Bismuth vanadate is a promising metal oxide semiconductor, as it absorbs visible light, and is abundant, non-toxic and cost-effective. The present study investigates the formation of bismuth vanadate thin films by the aerosol deposition (AD) method. Operating with layer formation at room temperature, AD offers advantages over other routes for the fabrication of photoactive thin film coatings, as no binders or sintering processes need to be applied. Furthermore, compared to traditional cold spraying, micrometer-sized particles can be used, resulting in coatings with thicknesses below 1 µm. Additionally, the lower kinetic energy of the feedstock powder particles enables the use of delicate substrates, such as FTO-coated glass, expanding the range of possible PEC device configurations. The process parameters explored in this study had considerable influence on the resulting coating microstructure, which in turn showed a significant impact on the photoelectrochemical performance.