For photocatalytic conversion of CO2 on TiO2, besides the well-known low energy conversion efficiency and poor products selectivity, several other obstacles exist but are seldom addressed, including (1) the weakened CO2 adsorption ability in the presence of H2O, (2) limited products/intermediates desorption, and (3) limited understanding of the surface intermediates conversion mechanism and catalysts deactivation mechanism. To tackle the above mentioned rarely studied obstacles, hybrid multifunctional photocatalysts, TiO2/MgAl-layer double hydroxides (LDHs), were  designed to efficiently adsorb, activate and convert CO2 and facilitate the desorption of products on the catalyst surface. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study was used to identify surface intermediates and to understand the reaction pathways. The rate of CO2 photoreduction to CO was higher at a slightly elevated temperature (175 oC) than at a lower temperature (50 oC). The dynamics of CO2 adsorption/desorption is also found to be a critical factor to govern the activity and stability of the photocatalyst.

CO2 photoreduction with H2O vapor over hybrid TiO2/MgAl layer double hydroxides

247th National Meeting (2014)

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