Nature of active species of (VO)2P2O7 for selective oxidation of n-butane to maleic anhydride

Abstract

TEM, EXAFS, FTIR, temporal analysis of products (TAP), stopped-flow desorption (SFD) and catalytic measurements of (VO)₂P₂O₇ are reported. The reduced interaction between (020) planes of (VO)₂P₂O₇ in samples prepared in an organic medium induces a charge localization on the V atoms of the coupled trans-vanadyl present in this plane, enhancing their catalytic reactivity in butane oxidation. Contiguous surface Brønsted sites (P—OH) also participate in the mechanism of selective oxidation. C-containing residues are present in relevant amount on the surface during catalytic experiments and give rise to a specific fouling of the active sites, but their possible role as co-catalysts in the transfer mechanisms of single activated species is also discussed.