Tahir M., Tahir B., Amin N., 2017, Photocatalytic Reverse Water Gas Shift CO2 Reduction to CO over Montmorillonite Supported TiO2 Nanocomposite, Chemical Engineering Transactions, 56, 319-324.
Photocatalytic CO2 reduction by H2 to CO via reverse water gas shift (RWGS) reaction over Montmorillonite (MMT) dispersed TiO2 nanoparticles has been investigated. MMT-clay supported TiO2 nanocomposites were prepared by a controlled and direct sol-gel method and were dip-coated over the monolith channels. The samples were characterized by XRD, FTIR, SEM, N2-adsorption-desorption and UV–visible spectroscopy. The performance of nanomaterials was tested in a continuous operation of monolith photoreactor for dynamic CO and hydrocarbons production under UV-light irradiation. The photoactivity of MMT/TiO2 nanocomposites loaded over the monolith channels was expressively increased for CO2 reduction to CO as the main product. The maximum yield of CO over 10 wt. % MMT-loaded TiO2 catalyst obtained was 25.95 µmole g-catal.-1 h-1 atselectivity 98 %, considerably higher than the amount produced over the pure TiO2 (8.52 µmole g-catal.-1 h-1). The other products detected with adequate amounts were CH4 and C2H6. This significant enhancement in CO evolution was evidently due to efficient light distribution with larger illuminated active surface area inside monolith micro-channels and hindered charges recombination rate over MMT dispersed TiO2. The reaction mechanism to understand the route of CO2 reduction by H2 via RWGS reaction is also proposed. This development has confirmed higher performance of green MMT/TiO2 photo-catalyst for continuous CO2 photo- reduction to cleaner fuels.
