Catalytic transformation of ethylene to propylene and butene over an acidic Ca-incorporated composite nanocatalyst

The direct conversion of ethylene to propylene (ETP reaction) has become critically important due to the growing demands for propylene as one of the key building blocks in the petrochemical industries and the depletion of appropriate resources for propylene production. In the present study, an acidic metal-incorporated composite nanocatalyst has been prepared and characterized using XRD, FTIR, FESEM, EDX, NH3-TPD, and N-2 physisorption analyses and applied to the ETP reaction. The maximum conversion of 77.8% was achieved over the catalyst at 723 K. The highest propylene yield (34.6 wt%) was obtained at 773 K, however. An increasing trend with temperature (573-823 K) was evident for the total light olefins selectivity, which amounted to 78.7 wt% at 823 K. The reaction rate increased constantly to 258 mol/(kg s) with the increase in the ethylene partial pressure. The remarkable performance of the composite catalyst in terms of propylene and butenes yields and its distinguished stability during the ETP reaction compared to the closely relevant HZSM-5 and HSAPO-34 counterparts, was attributed to both an appropriate porosity and a good compromise between the strength and amount of the acidic sites to an interestingly one-mode moderate acidity.