Oxidative dehydrogenation of ethane to ethylene by carbon dioxide over Cr/TiO2–ZrO2 nanocatalyst: Effect of active phase and support composition on catalytic properties and performance

Abstract

TiO2–ZrO2 supports with different compositions ranging from 0 to 100wt.% of ZrO2 were prepared by co-precipitation method and impregnated with 5wt.% of Cr2O3. The synthesized catalysts were characterized by XRD, FESEM, PSD, EDX, BET and FTIR techniques. Characterization studies revealed that the combination of different amounts of TiO2 and ZrO2 in the supports had obvious effect on the crystal structure, texture characteristic, 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/or ZrO2 in the synthesized samples. The FESEM and EDX images represented the production of homogeneous spherical type agglomerates within the nanometer range and uniform dispersion over the surface of all samples specially CrT75Z25 with an average particle size of about 38nm. The BET results depicted high surface area of Cr/TiO2–ZrO2 nanocatalysts. The highest catalytic activity and yield (C2H4 yield of 46% as well as 95% ethylene selectivity at 700°C) were acquired when 75wt.% TiO2 and 25wt.% ZrO2 were used as the support. It could be attributed to the smaller particles, higher surface area, better dispersion of active phase, and uniform morphology of CrT75Z25.