Highly Selective CO2 Conversion to Methanol in a Bifunctional Zeolite Catalytic Membrane Reactor

The hydrogenation of sequestrated CO2 to methanol can reduce CO2 emission and establish a sustainable carbon circuit. However, the transformation of CO2 into methanol is challenging because of the thermodynamic equilibrium limitation and the deactivation of catalysts by water. In the present work, different reactor types have been evaluated for CO2 catalytic hydrogenation to methanol. Best results have been obtained in a bifunctional catalytic membrane reactor (CMR) based on a zeolite LTA membrane and a catalytic Cu‐ZnO‐Al2O3‐ZrO2 layer on top. Due to the in situ and rapid removal of the produced water from the catalytic layer through the hydrophilic zeolite LTA membrane, it is effective to break the thermodynamic equilibrium limitation, thus significantly increasing the CO2 conversion (36.1 %) and methanol selectivity (100 %). Further, the catalyst deactivation by the produced water can be effectively inhibited, thus maintaining a high long‐term activity of the CMR. A bifunctional catalytic membrane reactor is developed for CO2 conversion to methanol, in which CO2 conversion to methanol and the by‐product water removal by hydrophilic zeolite LTA membrane is realized simultaneously. Attributing to in situ and continuous removal of water from the reaction system, the equilibrium limitation of CO2 conversion to methanol is broken, leading to a significant enhancement of CO2 conversion and methanol selectivity.