Influence of structural properties of catalysts at various stages of selective oxidation: from catalyst preparation to catalytic reactors

Solid oxides selective in mild oxidation exhibit a definite crystal morphology. Each crystal face displays a surface crystal field which rules the transformation of the reactant to a given product. The catalytic metastability of the surface which has to be maintained in the operating conditions prevailing in reactors depends on the reactivity of the bulk, because of oxygen diffusion process. Application to VPO, the catalyst for oxidation of n-butane to maleic anhydride, gives the opportunity to examine these properties in the series preparation–activation–catalysis–ageing, in relation to the type of catalytic reactor.