Photocatalytic CO2 reduction with H2O vapors using montmorillonite/TiO2 supported microchannel monolith photoreactor

In this study, the performance of a montmorillonite (MMT)/TiO2 coated monolith photoreactor was tested for the photocatalytic CO2 reduction. CH4 and CO were the main products having yield rates of 139 and 52 mole g catal.(-1) h(-1), respectively. The other adequately significant products were C2H4, C2H6, C3H6 and C3H8. The catalytic reactor performance for CH4 production was in the order of MMT-TiO2-monolith (139 mole g catal.(-1) h(-1)) > TiO2-monolith (82 mu mole g catal.(-1) h(-1)) > MMT-TiO2-cell (43 mole g catal.(-1) h(-1)) > TiO2-cell (7.7 mole g catal.(-1) h(-1)). The higher yield rates in monolith photoreactor were due to the higher illuminated surface area and efficient light utilization. In addition, the profound hydrocarbon yield rates over MMT/TiO2 nanocatalyst supported microchannels were due to the efficient production and utilization of charges. The reaction rate and the adsorption-desorption phenomenon was postulated according to the Langmuir-Hinshelwood (L-H) model. A simple kinetic equation, derived to model the coupled effect of adsorptive photocatalytic reduction and oxidation, fitted-well with the experimental data. (C) 2013 Elsevier B.V. All rights reserved.