Studies of mechanism of catalytic action on oxidative dehydrogenation of ethane over NiO

The mechanism of catalytic action on oxidative dehydrogenation of ethane over NiO has been investigated by means of O-2 - TPD, pulse measure, in situ Weiss magnetic methods and TAP(temporal analysis of products) experiments. It is found that the oxidized Ni is maintained in the course of ODHE reaction. The exchange between gas phase oxygen and nonstoichiometric oxygen (alpha ,beta oxygen species) is reversible, and the beta oxygen species (possibly O-),which exists both on the surface and in the bulk of the catalyst, shows higher selectivity towards ethylene than the ar one (possibly O-2(-),O-2(2-)) which just exists on the surface of the catalyst. The mechanism is proposed that the ethylene, which is not only the product but also the intermedium of forming CO2, forms from the reaction of the O- with ethane on the catalysts' surface, and the CO2 forms by the reaction of ethylene and/or C2H5 with O-2(-),O-2(2-) and O-2(,)The catalyst is reoxidized with the help of the reaction between oxygen vacancy, lattice oxygen and oxygen adsorpted.