Catalytic behaviour of a bifunctional system for the one step synthesis of DME by CO2 hydrogenation

tOne-step CO2hydrogenation reaction to dimethyl ether (DME) on a bifunctional system constitutedby Cu-ZnO-ZrO2(ZCZ) methanol synthesis catalyst and HZSM-5 zeolite was studied. The influenceof the reactor configuration in terms of combination procedure of the admixed samples on activ-ity, selectivity and DME yield has been evaluated. The results obtained at TR= 513 K, PR= 3.0 MPa andGHSV = 9000 NL gcat-1h-1show a superior DME productivity (4.4 mmol kgZCZ-1s-1) using the bifunctionalcatalyst prepared by physical mixing. A combined effect of active sites located at metal/oxide(s)-acidinterface was claimed as the main factor affecting the CO2conversion and DME productivity. The strongsurface acidity of ZCZ catalyst is not suitable to drive DME synthesis through a consecutive mechanism,while DME formation effectively proceeds on weak and medium acid sites of HZSM-5.

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