Spray-pyrolysis synthesis of CuMnO2 with the potential for photoelectrocatalysis

Amidst the global endeavor toward sustainable energy sources, photocatalysis appears as a promising gateway toward the production of solar fuels, in particular hydrogen. Hydrogen is currently a crucial reagent for vital industries such as petrol desulfurization, iron reduction and ammonia production, so the decarbonization of its production is a major challenge. CuMnO₂ (CMO), a p-type semiconductor, has been shown to enhance the efficiency of catalysts such as TiO₂ for the photoelectrocatalytic water splitting reaction. However, since pure CMO thin films have never been reported, its potential and limitations remain elusive. We used spray pyrolysis as a low-cost synthesis technique to simplify and accelerate the synthesis of CMO thin films directly on FTO substrates. CMO prepared in this manner exhibits activity toward photoeletrocatalytic water splitting and O₂ reduction. The activity has been found to be highly dependent on synthesis conditions, especially on the ratio and volume of precursors.