Amplification of PEC hydrogen production through synergistic modification of Cu2O using cadmium as buffer layer and dopant

Abstract A facile single step electro-synthesis is applied to develop Cu/Cu 2 O/Cd(OH) 2 thin films from the alkaline copper sulfate solution in presence of different levels of Cd 2+ . Cadmium implemented a synergistic effect, in the modification of Cu 2 O, through the diffusion into the bulk Cu 2 O and formation of Cd(OH) 2 buffer layer. The photoelectrochemical (PEC) performances of the optimized Cu/Cu 2 O/Cd(OH) 2 , significantly enhance the H + reduction photocurrent to −6.1 mA/cm 2 (1.5 times than that of pure Cu/Cu 2 O) and the solar energy conversion efficiency also improve up to 5.8%, which is 2 fold higher than the pure semiconductor. Experimental evidences, including SEM-EDX, XRD, Raman, XPS and EIS confirm that Cd modifies Cu 2 O through lowering the particle size with better crystallinity (accretive working surface area), minimizing resistance, increasing carrier concentration and rapid transfer of photogenerated charge carrier, resulting in suppression in electron-hole recombination, which facilitates the improved PEC performances.