Effect of secondary additives on the properties of vanadium‑aluminum mixed oxide tableted catalysts used in the oxidation of propane

The effect of adding secondary additives for tableting vanadium‑aluminum mixed-oxides, VAlO, on key physicochemical properties and on the catalytic performance in propane oxidation was investigated. Graphite was used as the primary shaping agent. The secondary additives were MgO, silica, BN, sepiolite, and ZnO. The hardness, fracture strength, and particle shape of the secondary additives were associated to the changes of the mechanical strength and porosity of the tablets. There was a compromise between mechanical strength and loss of mesoporosity and surface area. Meanwhile, the additives did not establish a chemical interaction with the VAlO material. Therefore, the secondary additives may act as co-catalysts during propane oxidation. BN and sepiolite were best for promoting both the reactivity of the catalytic formulations and the production of propene. This promotion may be due to the combination of a redox mechanism over the VAlO phase and to a surface radical mechanism occurring over the active moieties of BN and sepiolite. [Display omitted] •Tablets of vanadium-aluminum mixed oxide were manufactured using graphite as primary additive.•The effect of secondary tableting additives was investigated.•Secondary additives change mechanical resistance according to their hardness, fracture toughness, and shape.•A compromise between mechanical strength and loss in mesoporosity and surface area must be made.•Boron nitride and sepiolite act as co-catalysts in propane oxidation.