Aerosol deposition of CuFeO2 photo-cathode coatings for solar hydrogen generation

Photoelectrochemical (PEC) water splitting is a promising route for sustainable hydrogen production. CuFeO₂ is a potential photocathode material for PEC cells thanks to its suitable band gap (~1.5 eV), p-type conductivity, and composition based on abundant, non-toxic elements. However, its performance is limited by charge carrier recombination within the film and at the substrate interface. This study explores the use of Aerosol Deposition (AD) to fabricate CuFeO₂ thin films, aiming to minimize recombination losses and improve film quality, while taking advantage of the high deposition rates and low cost of AD. CuFeO₂ powders were synthesized via solid-state reaction and sprayed onto AISI 304 steel and FTO-glass substrates. Both full coating deposition and single-impact tests were carried out to evaluate particle deformation and bonding. The effect of particle size, carrier gas type, pressure, and substrate temperature were investigated to define a window of deposition. Optimum process parameters were then tuned to obtain thin films (<1 μm thick) for sunlight harvesting. Coating microstructure and phase composition were investigated by SEM, XRD and Raman spectroscopy. Optical properties of CuFeO2 coatings were analysed by UV-Vis spectroscopy, while the PEC performance was estimated through Amperometry under simulated sunlight (AM1.5G). The results demonstrate the potential of AD for scalable, catalyst-free fabrication of efficient CuFeO₂-based photocathodes.