Abstract
We studied the photocatalytic water splitting reaction by CoOx/TiO2 nanocomposites with p-n junction characteristic. CoOx/TiO2 nanocomposites were synthesized by non-aqueous sol-gel method with microwave system, and the Co loading was controlled by adjusting the concentration of precursors. The composition, oxidation state and structure of CoOx/TiO2 nanocomposites were characterized by XRD, UV, TEM, XPS, ICP-MS, EPR and XAS. The catalysts were composed of nanocrystalline anatase TiO2 and cobalt oxide nanoparticles that were too small to be directly observed in some of the catalysts. The catalysts were applied for the photocatalytic water splitting under ultraviolet irradiation using methanol as a sacrificial reagent. The photocatalyst with molar ratio of Co and Ti (Co/Ti) of 2.9% showed the highest hydrogen production rate (1849.4 □mol g-1 h-1), suggesting that photo-generated electrons and holes were separated effectively in the photocatalyst. Beside, the catalyst gave CO2 as the only by-product, and it was stable for long-term reaction.