Layer structured bifunctional monolith catalysts for energy-efficient conversion of CO2 to dimethyl ether

A monolith supported bifunctional catalyst for the direct conversion of CO2 to dimethyl ether was developed and evaluated. The catalyst consists of a layer structured configuration, in which a CuO/ZnO/ZrO2 component for methanol synthesis using CO2 as feedstock and a Ferrierite zeolite component for the subsequent dehydration reaction are washcoated onto the channel surfaces of a metallic monolith substrate as two consecutive layers. The metal substrate provides heat conduction to regulate the catalyst bed temperature. The layered configuration significantly improves the synergistic effects of the two components, resulting in a 20% increase in the pro-ductivity for dimethyl ether at 240 degrees C as compared with the conventional catalysts with the two components being blended in various levels of proximity. Additionally, the layer structured design minimizes the undesirable interaction between the two components and drastically improves the on-stream durability of the catalyst. No activity decline was observed in a 146-h performance test.