Effect of the zirconia-titania catalyst modification and CO2/CH4 ratios on CO2 coupling reaction with methane

•The nanoscale crystals between 20 and 37 nm of 5%ZrO2/TiO2 correlated with surface acidity.•The H2 reduction for each catalyst affected by Zr oxide interaction with Ti oxide.•The formation of acetic acid via CH4 dissociation to CH3* and H* surface species coupled with CO2 was affected from surface oxides interaction between ZrO2 with TiO2.•The CO2/methane gas ratio played essential in controlling the reaction on CO2 coupling with methane in terms of molecular adsorption and dissociation over catalyst surface. The CO2 utilization for coupling reaction with methane for the production of C1 building block chemicals was studied. The influence of surface oxides of zirconia-titania catalysts and CO2/methane gas ratios were investigated to promote methane activation and coupling with CO2 for the production of value-added chemicals of acetic acid, ethane and ethylene. The synthesized catalysts by three impregnation methods assisted by microwave irradiation, exhibited different nanoscale crystal sizes and were characterized by various techniques of XRD, TEM, BET, NH3-TPD and H2-TPR. The anatase and tetragonal phases of ZrO2/TiO2 framework were identified and the synthesized catalysts showed an increase of surface acidity with distinct H2 reduction patterns for each catalyst as result of Zr oxide interaction with Ti oxide. Methane activation was observed and the coupling reaction produced ethane and ethylene and was affected via modified catalysts. Despite ongoing reaction, CO2 coupling reaction formulated acetic acid and consumed methyl surface species over catalyst then dimerized to form ethane and ethylene. It was found that the obtained products from CO2 coupling were altered by the variation in methane dissociation due to changing CO2/methane ratios, at which higher CO2/methane ratio (90%:10%) showed the highest methane dissociation and CO2 coupling reaction. [Display omitted]