A Cu2O/TiO2 heterojunction thin film cathode for photoelectrocatalysis

A thin film heterojunction photocathode was developed consisting of 100 nm of n-type titanium dioxide (TiO2) cathode surface deposited on p-type cuprous oxide (Cu2O). The cuprous oxide was deposited electrochemically on Ti foil. A photocurrent of 0.7 mA/cm2 (at −1 V bias) and an open circuit photovoltage of 460 mV were obtained under an illumination of 700 W/m2. The photoresponse as a function of pH demonstrated that the TiO2 film protected the Cu2O underlayer against corrosion. These results suggest that using a simple and inexpensive heterostucture configuration, the corrosion limitations of Cu2O alone may be overcome while maintaining a relatively high efficiency for photoelectrolysis.