Catalytic activity for direct CO2 hydrogenation to dimethyl ether with different proximity of bifunctional Cu-ZnO-Al2O3 and ferrierite

Dimethyl ether (DME) can be directly synthesized by carbon dioxide (CO2) hydrogenation over bifunctional catalysts, which are suffered from various deactivation mechanisms caused by incompatible integrations of metal oxides and solid acid zeolites according to their different proximity. The core-shell structured integrations of Cu-ZnO-Al2O3 metal oxide (CZA) and ferrierite zeolite (FER) are investigated for direct CO2 hydrogenation to DME. The detrimental and undesired surface properties formed by a possible ion-exchange of FER surfaces with the relatively volatile metal ions from Cu-ZnO-Al2O3 surfaces were effectively suppressed by applying the physically-coated interlayers with SiO2 ([email protected]) compared to the powder-mixed one (CZA/FER), where an intimate proximity of metal oxides and FER was eventually responsible for an increased CO selectivity and deactivation rate. The SiO2 interlayers to isolate the CZA and FER with a suppressed migration of metal ions to FER surfaces further stabilized the active Cu-ZnO nanoparticles and acidic sites of FER surfaces.