A high-efficiency and stable cupric oxide photocathode coupled with Al surface plasmon resonance and Al2O3 self-passivation

The key to achieving high performance in photoelectrochemical (PEC) water splitting is the design of efficient and stable photoelectrode structures. Herein, we firstly synthesized a novel and high-photoactivity CuO/Al photocathode and then the Al2O3 passivation layer was further introduced through a spontaneous oxidation process in air to protect the photocathode against photocorrosion. On account of the localized surface plasmon resonance (LSPR) of Al nanoparticles (NPs) in conjunction with surface passivation of the Al2O3 layer, the obtained CuO/Al/Al2O3 photocathode exhibits a high photocurrent density of −0.95 mA cm−2 at −0.55 V vs. Ag/AgCl and photocorrosion stability of 89.5% after 1 h.