Effect of hydrogen spillover in hydrogenolysis and cracking of butane on Co-niobia-silica catalysts

Abstract

A series of Co-Nb 2 O 5 -SiO 2 , Co-SiO 2 and Co-Nb 2 O 5 catalysts with 10 wt.% Co and 10 wt.% niobium oxide were prepared following three sol-gel procedures: colloidal, polymeric, and an intermediate one. Impregnated mixed oxides and oxides were also prepared, as well as physical mixtures of impregnated oxides in order to obtain information about the existence of the spillover species. These catalysts were investigated using several techniques: N 2 adsorption and desorption curves at 77 K, XRD, FTIR and XPS. H 2 -chemisorption, H 2 -TPR and H 2 /D 2 exchange were used to prove the existence of the spillover effect. The activity of these catalysts was evaluated in hydrogenolysis and cracking of butane. Their increased stability in hydrogen was associated to a scavenger effect, enhanced by the spillover species.