Abstract
Hydrogen will play a major role in the necessary transition towards a decarbonized energy economy. Solar water splitting is a renewable hydrogen generation pathway, but its implementation at large scales requires the development of cost efficient electrode fabrication methods.
In recent years, we have explored cold-gas-spray deposition of semiconductor particles as a solvent-free, scalable process for the manufacture of water splitting photoelectrodes. While this method works well with a small set of light-absorbing materials, including WO3 or TiO2, it is difficult to implement for semiconductors such as Fe2O3 or BiVO4, for which unfavorable charge carrier dynamics pose severe limitations on the coating thickness.
To overcome this problem, we are developing aerosol cold gas spraying (aerosol deposition method) as coating technology. This vacuum-based deposition method enables the use of sub-micrometer particles, resulting in thin semiconductor layers, while expanding the range of applicable supports to include fragile substrates such as FTO-coated glass. Initial test coatings with undoped BiVO4 have produced electrodes with photocurrent densities of up to 2mA/cm2.
In this presentation, we describe the experimental setup and the parameter selection process for the FTO/BiVO4 system, and we furthermore discuss the relationship between experimental spraying parameters and the thickness, morphology, and physical and electrochemical properties of the resulting BiVO4 layers.
