The beneficial utilization of natural zeolite in preparation of Cr/clinoptilolite nanocatalyst used in CO2-oxidative dehydrogenation of ethane to ethylene

• Decrease in both synthesis cost and time of Cr-based catalysts.
• Size reduction of Cr particles to nanometer scale and noticeable increase of surface area.
• Attainment of superior metal–support interaction and uniform dispersion of Cr species.
• High ethylene selectivity even at 700 °C (>95%).
• Enhancement of ethylene yield up to 10% using combined-treated clinoptilolite.

The oxidative dehydrogenation of ethane in the presence of CO2 was investigated over a series of Cr-impregnated clinoptilolite catalysts exploring the natural zeolitic support potential. The as-synthesized nanocatalysts were characterized by XRD, BET, FESEM, TEM, ICP, FTIR, EDX and TPD-NH3 techniques. It was found that Cr supported on the acid treated clinoptilolite followed by NH4NO3 treatment nanocatalyst effectively dehydrogenated ethane to ethylene in the presence of CO2 at 700 °C, giving 39.3 and 98.8% ethylene yield and selectivity, respectively. A promoting effect of CO2 on the ethane dehydrogenation over the most active catalyst was also observed.

CO2 assisted dehydrogenation of ethane in the presence of was investigated over a series of Cr-impregnated clinoptilolite catalysts exploring the natural zeolitic support's potential and assessing the individual and synergistic effects of HNO3 and NH4NO3 treatments of clinoptilolite as a support on the physicochemical properties and catalytic performance. The characterization results generally indicated the remarkable synergetic effect of acid treatment on the surface morphology and Cr dispersion, especially when it is coupled with ion exchange treatment. The catalytic tests illustrated that the chromia supported catalysts exhibit a reasonable catalytic performance. By employing treated clinoptilolite supports, an increase of the catalytic activity accompanied by a slight decrease of the selectivity for ethylene was observed. It was found that Cr supported on the NH4NO3/HNO3 treated clinoptilolite nanocatalyst effectively dehydrogenated ethane to ethylene in the presence of CO2 at 700 ̊C, giving 39.3% ethylene yield with a selectivity of 98.8%.Figure optionsDownload as PowerPoint slide