It has been widely reported that addition of copper or copper oxide species on TiO2 photocatalyst can enhance reduction of CO2 to fuels under solar radiation. However, it is not clear in the literature which copper species (Cu2+, Cu+, Cu0) is the most active. Furthermore, surface defects such as oxygen vacancies may have significant effects on catalytic activity of TiO2. In this work, we prepared CuOx/TiO2 catalysts with different Cu states and employed in situ FTIR to gain insight into the interaction mechanism of CO2 and H2O with oxidized and reduced CuOx/TiO2 catalysts. We found CO2 is spontaneously dissociated into CO on reduced CuOx/TiO2, but not on oxidized CuOx/TiO2, possibly because the defective sites facilitate electron transfer. In addition, Cu+ ions are more active than Cu2+ and Cu0 to accelerate the transformation of negative CO2- species and the formation of CO on the surface of TiO2.

Solar fuel production from CO2 photoreduction on CuOx/TiO2 nanoparticles: The role of surface oxygen vacancy and copper species

243rd National Meeting (2012)

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