Dehydrogenation of Ethane to Ethylene with Carbon Dioxide over Chromium Oxide Catalyst Utilizing NH4NO3 Treated Clinoptilolite as Support

The oxidative dehydrogenation of ethane in the presence of CO2 was investigated over Cr-impregnated clinoptilolite catalysts. Furthermore, the effects of NH4NO3 treatment of clinoptilolite as a support on the physicochemical properties and catalytic performance was investigated. The as-synthesized nanocatalysts were characterized by XRD, BET, FESEM and EDX techniques. Based on the characterization techniques, higher dispersion of chromium species could be achieved using modified clinoptilolite support due to much higher surface area; and uniform and open morphology. This reflects in higher content of high-valent Cr species stabilized in comparison with raw clinoptilolite, which accounts for its better catalytic performance. The catalytic tests illustrated that the chromia supported catalysts exhibit a reasonable catalytic performance. By employing treated clinoptilolite support, an increase of the catalytic activity accompanied by a slight decrease of the ethylene selectivity was observed. It was found that Cr supported on the NH4NO3 treated clinoptilolite nanocatalyst effectively dehydrogenated ethane to ethylene in the presence of CO2 at 700°C, giving 34.2 and 98.2% ethylene yield and selectivity, respectively. This could be well explained on the basis of more accessibility and better Cr species dispersion.

کلیدواژه ها:

Natural zeolite ، Cr ، Clinoptilolite ، Dehydrogenation ، Ethane ، Ethylene