Conversion of Ethane to Ethylene in the Presence of Carbon Dioxide over Cr-K/TiO2-ZrO2 Nanocatalyst Synthesized via Coprecipitation and Impregnation Methods

In this investigation, TiO2-ZrO2 combined support with composition of 25wt% ZrO2 and 75wt% TiO2 was prepared by coprecipitation method and impregnated with 5 wt% of Cr2O3 and 3 wt% of K2O. The synthesized samples were characterized by XRD, FESEM, EDX, BET, and FTIR techniques. All characterization studies revealed that the deposition of Cr2O3 and K2O on the TiO2-ZrO2 combined support had obvious effect on the surface and structural properties and catalytic activity in the oxidative dehydrogenation of ethane to ethylene by carbon dioxide as a soft oxidant. The XRD analysis confirmed the formation of crystalline TiO2 and ZrO2 in the synthesized samples. The FESEM and EDX images represented the formation of homogeneous spherical type agglomerates within the nanometer range and uniform dispersion over the surface with an average particle size of about 75 nm. The BET results depicted high surface area of synthesized samples. Cr-K/TiO2-ZrO2 catalyst exhibited high performance towards the selective conversion of ethane to ethylene in the presence of CO2 (C2H4 yield of 39% as well as 97% ethylene selectivity at 700 °C), wherein Cr2O3 improved the conversion of ethane as a redox active phase and K2O enhanced the selectivity of ethylene, acting as a basic promoter.