Bandgap Reduction and Enhanced Photoelectrochemical Water Electrolysis of Sulfur-doped CuBi2O4 Photocathode

As interest in hydrogen energy grows, eco-friendly methods of producing are being explored. CuBi2O4 is one the p-type semiconductor cathode materials that can be used for photoelectrochemical production via environment-friendly water electrolysis. has a bandgap 1.5 – 1.8 eV which allows it to photogenerate electrons and holes from absorption visible light. This study investigated effect sulfur doping on reduction properties CuBi2O4. Sulfur-doped thin films were electrochemically synthesized using nitrate-based precursor solution with thiourea. was followed by two-step annealing an Ar atmosphere, effectively prevented oxidation sulfur. Sulfur up 0.1 at% led expansion lattice volume The reduced 1.9 increasing concentration, resulted enhancement current density ~240%. X-ray photoelectron spectroscopy showed sulfur-doping oxygen vacancies confirming enhanced bandgap, not any extrinsic factor such as vacancies. Further studies sulfur-doped improve surface coverage expected lead more promising material.