Enhanced NiO Dispersion on a High Surface Area Pillared Heterostructure Covered by Niobium Leads to Optimal Behaviour in the Oxidative Dehydrogenation of Ethane

Abstract

Nb‐containing siliceous porous clay heterostructure (PCH) (Nb‐content from 0 to 30 wt%), prepared from a bentonite, has been used as effective support in the preparation of supported NiO catalysts (with NiO loading from 15 to 80 wt%). Supports and NiO‐containing catalysts have been characterized by several physicochemical techniques, and tested in the oxidative dehydrogenation of ethane. The characterization results on Nb‐containing supports show the presence of well‐anchored Nb 5+ species, without the formation of Nb 2 O 5 crystals. A high dispersion of nickel oxide (which presents a low crystallinity) has been observed when using the Nb‐containing PCH supports. In addition, when NiO is supported on these Nb‐containing porous clays, it displays a higher effectiveness in the ODH of ethane (ethylene selectivity of ca. 90 %) than NiO supported on the corresponding Nb‐free siliceous PCH or on Nb 2 O 5 (ethylene selectivity of ca. 30 and 60 %, respectively). Factors such as the NiO‐Nb 5+ interaction, NiO particle size and the properties of surface Ni n+ species have shown to be determining for the catalytic performance.