Al2O3 support triggering highly efficient photoreduction of CO2 with H2O on noble-metal-free CdS/Ni9S8/Al2O3

Noble-metal-free photocatalysts are promising for economic and efficient conversion of solar energy into chemical energies. Herein, a highly efficient CO evolution, with an evolution rate of 12.1 mu mol h(-1), is achieved from the visible-light-driven photoreduction of CO2 with H2O on a noble-metal-free CdS/Ni9S8/Al2O3 photocatalyst. The CO evolution on CdS/Ni9S8/Al2O3 is comparable to that on the noble-metal-based CdS/Pt/Al2O3 photocatalyst (10.6 mu mol h(-1)), but 11 times higher than that on the Al2O3-free CdS/Ni9S8 (1.1 mu mol h(-1)) photocatalyst. The Al2O3 support facilitates the separation of the photogenerated electron-hole pairs, CO2 adsorption and production of protons for reducing CO2, thus enhancing the CO evolution. These results will open a new door for rationally fabricating efficient noble-metal-free photocatalysts, and favor the transition to solar energy economy.