Hybrid Cu-ZnO-ZrO2/H-ZSM5 system for the direct synthesis of DME by CO2 hydrogenation

One-step CO2 hydrogenation reaction to dimethyl ether (DME) was studied on a hybrid system characterized by different reactor bed configurations (physical mixing, dual-bed and mono-bed). Homemade Cu-ZnO-ZrO2 methanol catalytic system and a commercial H-ZSM5 zeolite were used to realize the hybrid system. The influence of preparation method on activity, selectivity and yield in the temperature range of 453-513 K at 3.0 MPa and CO2/H-2/N-2 feed concentration of 3/9/1 has been evaluated. The results obtained under kinetic conditions show a superior specific productivity of ca. 430 g(total MeOH) kg(cat)(-1)h(-1) at 513 K using the hybrid catalyst prepared by physical mixing. A combined effect of sites located at metal/oxide(s)-acid interface to drive DME synthesis through a consecutive mechanism was claimed as the main factor affecting the CO2 conversion and DME productivity. (C) 2013 Elsevier B.V. All rights reserved.