Silica-doped TiO2 as support of gallium oxide for dehydrogenation of ethane with CO2

Dehydrogenation of ethane to ethylene in the presence or absence of CO2 over silica-doped TiO2 supported Ga2O3 catalysts was investigated. The silica doping of TiO2 support greatly improved the dehydrogenation activity in the absence of CO2, which can be ascribed to the increased acid sites. The initial activity in the presence of CO2 decreased after the silica doping, due to the reduction in reverse water-gas shift ability. However, the selectivity as well as the stability increased, resulting in higher steady ethylene yield. A dynamic process consisting of alternative oxidative dehydrogenation/regeneration cycles by gasifying the carbon deposit with air for 10 min after each cycle of 6 h reaction was also performed and relatively stable ethane conversion similar to 30% and ethylene yield similar to 25% can be achieved. The different catalytic behaviors are probably associated with the different state of gallium species, caused by the different interaction between the Ga2O3 and support.