Synthesis and characterization of Cu–Zn/TiO 2 for the photocatalytic conversion of CO 2 to methane.

Different Cu–Zn/TiO2catalysts were synthesized by using the wet impregnation method. The prepared catalysts were used for the conversion of CO2into methane by photocatalysis. Various characterization techniques were used to observe the surface morphology, crystalline phase, Brunauer–Emmett–Teller (BET) surface area, presence of impregnated Cu and Zn, and functional group. Scanning electron microscope analysis showed spherical morphology, and slight agglomeration of catalyst particles was observed. BET analysis revealed that the surface area of the catalyst was decreased from 10 to 8.5 m2/g after impregnation of Cu and Zn over TiO2support. Synergetic effect of Cu and Zn over TiO2support (Cu2.6/TiO2, Zn0.5/TiO2and Cu2.6–Zn0.5/TiO2) and the effects of Cu loading (0, 1.8, 2.1, 2.6 and 2.9 wt%) were also investigated at different feed molar ratios of H2/CO2(2:1 and 4:1). The Cu2.6–Zn0.5/TiO2catalyst showed a maximum conversion of 14.3% at a feed molar ratio of 4. The addition of Zn over the catalyst surface increased the conversion of CO2from 10% to 14.3% which might be due to synergy of Cu and Zn over TiO2support. [ABSTRACT FROM PUBLISHER]