Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phase Formation

Co/TiO2 catalysts with different cobalt loadings (3.8, 7.5 and 15 wt%) were prepared by impregnation method of Co(NO3)2 6H2O over titania. Samples containing Co(NO3)2·6H2O TiO2 in stoichiometric proportions order to obtain CoTiO3 Co2 TiO4 phases also synthesized. The effect the calcination treatment at two temperatures, 550 1150 °C, was investigated. Characterizations several techniques, such as XRD, UV–vis–NIR, DRS, Raman XPS, carried out. XRD showed coexistence three phases: CoTiO3; Co2TiO4 Co3O4 after while high temperature (1150 °C) led single-phase systems (CoTiO3 or Co2TiO4). Diffuse reflection XPS spectroscopy that divalent occupies octahedral sites ilmenite phase, both tetrahedral spinel phase. catalytic performances evaluated oxidative dehydrogenation reaction (ODH) ethane ethylene, a function Co content for temperatures phases. Co(7.5)/TiO2 most active, although conversion decreased first 150 min reaction, reaching values comparable those however, confirmed having best selectivity ethylene comparison bulk phases, Co2TiO4. influence mixture composition, specifically presence water, percentages, There is decrease overall an increase when percentage water increases. This behavior can likely be attributed surface concentration hydroxyl species (OH), resulting heightened acidity.