TURKISH JOURNAL OF CHEMISTRY, cilt.45, sa.1, ss.231-247, 2021 (SCI-Expanded)
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 gamma-Al2O3 at atmospheric pressure and at temperatures of 210 degrees C and 260 degrees C using a CO2:H-2 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 degrees C. Cu-Ho-Ga/gamma-Al2O3 catalyst shows the highest formation rate of methanol (90.3 mu mol CH3OH/g cat/h) and DME (13.2 mu mol DME/g cat/h) as well as the highest selectivity towards methanol and DME (39.9 %) at 210 degrees C using a CO2:H-2 1:9 feed ratio. In both the thermodynamic analysis and reaction results, the higher concentration of H-2 in the feed and lower reaction temperature resulted in higher DME selectivity and lower CO production rates.