EFFECTS OF PREPARATION METHOD ON CATALYTIC BEHAVIOR OF Ni-Me (Me = Co, Nb)/γ-Al2O3 FOR OXIDATIVE DEHYDROGENATION OF ETHANE

Catalysts based on Ni-Me (Me = Co, Nb) supported on γ-Al2O3 were prepared by the coprecipitation-chemical deposition method via reflux, and hydrothermal method for oxidative dehydrogenation of ethane. For coprecipitation method, ammonia and urea were used as precipitating agents. In both methods, the Ni content was 30 wt.%, whereas that of Me (Co, Ni) was 5 wt.%. The activity and selectivity towards ethylene appeared to depend strongly on the composition of the catalysts and, interestingly, on the preparation conditions. In the present article, it is shown that mixed hydrothermal samples using urea showed the best performance. Specifically, the hydrothermally prepared NiNb/γ-Al2O3 sample was the one that showed the highest values. The introduction of Nb to Ni framework allowed to enrich with nucleophilic oxygen sites displayed via X-ray photoelectronic spectra (XPS) which lead to the formation of low reducible and selective sites.