CO2 hydrogenation to methanol and dimethyl ether at atmospheric pressure using Cu-Ho-Ga/γ–Al2O3 and Cu-Ho-Ga/ZSM-5: Experimental study and thermodynamic analysis

CO2 valorization through chemical reactions attracts significant attention due to the mitigation of greenhouse gas effects. This article covers the catalytic hydrogenation of CO2 to methanol and dimethyl ether using Cu-Ho-Ga containing ZSM-5 and γ-Al2O3 at atmospheric pressure and at temperatures of 210 °C and 260 °C using a CO2:H2 feed ratio of 1:3 and 1:9. In addition, the thermodynamic limitations of methanol and DME formation from CO2 was investigated at a temperature range of 100?400 °C. Cu-Ho-Ga/γ-Al2O3 catalyst shows the highest formation rate of methanol (90.3 μmolCH3OH/gcat/h ) and DME (13.2 μmolDME/gcat/h) as well as the highest selectivity towards methanol and DME (39.9 %) at 210 °C using a CO2:H2 1:9 feed ratio. In both the thermodynamic analysis and reaction results, the higher concentration of H2 in the feed and lower reaction temperature resulted in higher DME selectivity and lower CO production rates.