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/Cu2O/Cd(OH)2 thin films from the alkaline copper sulfate solution in presence of different levels of Cd2+. Cadmium implemented a synergistic effect, in the modification of Cu2O, through the diffusion into the bulk Cu2O and formation of Cd(OH)2 buffer layer. The photoelectrochemical (PEC) performances of the optimized Cu/Cu2O/Cd(OH)2, significantly enhance the H+ reduction photocurrent to -6.1 mA/cm2 (1.5 times than that of pure Cu/Cu2O) 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 Cu2O 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.