Scalable Reduced Graphene Oxide Conductive Layer‐Based Particulate Photocathodes for Photoelectrochemical Water Splitting

Abstract Particle transfer method photoelectrodes show superior photoelectrochemical performance compared to traditional powder‐based methods, making them a promising solution for solar water splitting in sustainable energy. This study introduces an innovative nonvacuum particle transfer method for fabricating photoelectrodes on a conductive carbon substrate, addressing the challenges associated with the high costs and vacuum deposition processes of traditional methods. Utilizing a p‐type CuFeO ₂ powder semiconductor, a unique substrate is developed by applying a graphene oxide layer mixed with a small amount of silica binder on the particle layer's backside through ultrasonic atomization spraying. This layer is converted into multilayered reduced graphene oxide (ML‐rGO) via wet chemical reduction, resulting in a substrate boasting a high work function (4.8 eV), alongside remarkable chemical stability, mechanical strength, and conductivity. The fabricated CuFeO ₂ photocathode demonstrated an onset potential of 0.97 V versus RHE and a photocurrent density of 1.5 mA cm ⁻² at 0.6 V versus RHE for H ₂ O ₂ reduction. Further enhancement is achieved by depositing Pt as a cocatalyst, which ensured stability for over 20 h in an alkaline medium for water splitting. This study sets a new benchmark for developing CuFeO ₂ ‐based photocathodes, paving the way for broader particle transfer method applications.