Cu2O/CuO photocathode with improved stability for photoelectrochemical water reduction

A p-type cuprous oxide (Cu2O) photocathode covered with a thin layer of cupric oxide (CuO) was prepared by fast annealing of a copper foil via H-2-O-2 flame. The as-prepared composite photocathode is characteristic of a junction structure formed between the (110) plane of Cu2O and the (111) plane of CuO. The Cu2O/CuO composite photocathode showed improved stability for photoelectrochemical (PEC) water reduction by increasing the coverage of CuO on Cu2O.