Photocatalytic Evolution of Hydrogen on CuFe2O4

We investigated the technical feasibility of photochemical hydrogen release based on CuFe2O4 powder dispersion in an aqueous electrolyte containing a reducing agent (\({\text{S}}_{2} {{\text{O}}_{3}}^{ - 2}\)). The oxide combines an average resistance to corrosion and an optimum inter-referred band Eg of 1.67 eV. The intercalation of a small amount of oxygen should be accompanied by partial oxidation of Cu+ to Cu2+ involving a p-type semi-conductivity. The oxidation S2− inhibits the photo-corrosion, and the evolution of H2 increases in parallel with the formation of polysulfides. Most of H2 is produced when p-CuFe2O4 is connected to n-ZnO formed in situ. The release of H2 is mainly on CuFe2O4, whereas, the oxidation of S2− takes place on the surface of ZnO and the hetero-system CuFe2O4/ZnO is optimized with respect to certain physical parameters. The photoelectrochemical production of H2 is a multi-step process whose decisive step is the arrival of electrons at the interface due to their low mobility. Remarkable performance with a rate of 6.74 (μmol g−1 min−1) cm3 h−1 hydrogen evolution in 0.1 M \({\text{S}}_{2} {{\text{O}}_{3}}^{ - 2}\) (pH 13) is recorded.