Photocatalytic reverse water gas shift CO2 reduction in a monolith photoreactor

Abstract

The photosynthesis of fuels via reverse water gas shift (RWGS) reaction has potential to alleviate both global warming and energy crises. In this study, a microchannel monolith catalytic photoreactor has been investigated for CO2 reduction with H2 reductant through RWGS reaction. The channels were dipped-coated with indium (In) modified TiO2 nanoparticle. The monolithic catalysts were characterized by XRD, SEM, N2 adsorption-desorption and UV-Vis spectroscopy. In-doped TiO2 inhibited crystal growth and produced mesoporous anatase TiO2 nanoparticles. Doping In in TiO2 also increased the surface area and enlarged the band gap. The photocatalytic CO2 reduction to CO over TiO2 was 1.7 fold high with H2 as reductant than using H2O vapours. The performance of In/TiO2 monolithic catalyst for CO production during CO2 reduction with H2 was 18 times higher than the un-doped TiO2. The reaction in the monolith reactor also produced smaller amounts of CH4, C2H4, C2H6, C3H6 and C3H8 hydrocarbons. These results confirmed higher performance of monolith photoreactor and In-doped TiO2 catalyst for CO2photoreduction with H2 to fuels.