Photocatalytic CO2 reduction by CH4 over montmorillonite modified TiO2 nanocomposites in a continuous monolith photoreactor

Abstract In this study, the performance of montmorillonite (MMT) modified TiO 2 nanocomposites for photocatalytic CO 2 reduction with CH 4 in a continuous monolith photoreactor has been investigated. The MMT modified TiO 2 nanocomposites were dip-coated over monolith channels and were characterized by XRD, SEM, TEM, XPS, N 2 -adsorption–desorption and UV–vis spectroscopy. The MMT produced anatase phase of TiO 2 and reduced TiO 2 crystallite size from 19 nm to 13 nm. CO was the major reduction product with a yield rate of 237.5 μmol g-catal. −1 h −1 over 10 wt.% MMT-loaded TiO 2 at 100 °C, and CO 2 /CH 4 feed ratio 1.0. The photoactivity of MMT-loaded TiO 2 monolithic catalyst was 2.52 times higher than bare TiO 2 . Likewise, low concentrations of C 2 H 6 , CH 3 OH, C 3 H 6 and C 3 H 8 were detected in the products mixture. These results inferred MMT modified TiO 2 and monolith photoreactor were beneficial for enhancing photocatalysis process with appreciable productivity. The stability test revealed photoactivity of MMT-loaded TiO 2 nanocomposites partially diminished in recycle runs.