Enhanced Photoelectrochemical Activity by Autologous Cd/CdO/CdS Heterojunction Photoanodes with High Conductivity and Separation Efficiency.

The development for hydrogen from solar energy has attracted great attention due to the global demand for clean, environmentally friendly energy. Herein, autologous Cd/CdO/CdS heterojunctions were prepared in a carefully controlled process with metallic Cd as the inner layer and CdO as the interlayer. Further research revealed that the transportation and separation of photogenerated pairs were enhanced due to low resistance of the Cd inner layer and the type II CdO/CdS heterojunction. As a result, the optimized Cd/CdO/CdS heterojunction photoanode showed outstanding and long-term photoelectrochemical activity for water splitting, with a current density of 3.52 mA cm-2 , or a benchmark specific hydrogen production rate of 1.65 μmol cm-2  min-1 at -0.3 V versus Ag/AgCl, by using the environmental pollutants of sulfide and sulfite as sacrificial agents.