An orthorhombic Mo3VOxcatalyst most active for oxidative dehydrogenation of ethane among related complex metal oxides

Abstract

Four distinct structural types (orthorhombic, trigonal, tetragonal and amorphous) of Mo₃VO_x catalyst were each synthesized by a hydrothermal method as a single phase, characterized structurally and tested for oxidative dehydrogenation of ethane. A common structural feature of the catalysts is that the materials are a layer-type structure and constructed with pentagonal {Mo₆O₂₁} units. The arrangement of the pentagonal units can form heptagonal channels to create different structural features. The orthorhombic Mo₃VO_x catalyst has microporosity due to the open heptagonal channels adsorbing nitrogen molecules and showed the highest activity for the reaction among four distinct catalysts. Furthermore, this phase appeared to be most active, currently, compared to other complex metal oxide catalysts reported. An observed positive relation between the microporosity and the oxidation activity suggests that the catalytic oxidation takes place at the heptagonal channels.