Platinum aluminophosphate oxynitride (Pt-AlPON) catalysts for the dehydrogenation of isobutane to isobutene

The catalytic dehydrogenation of isobutane to isobutene over two series of platinum-supported aluminophosphate oxynitride (Pt-AlPON) catalysts, contai ning different amounts of nitrogen and synthesized using two different plat inum precursors, was studied. The impregnation and platinum reduction proce sses result in a partial loss of nitrogen and a decrease in the specific su rface area of the AlPON precursors. The surface and bulk structures of the catalysts are functions of the nitrogen content of the solid. At low nitrog en contents (less than or equal to 6% w/w), the nitrogen is found mainly on the surface of the catalyst as an -NHx species. Above 6% w/w, nitridation of the bulk begins. The basicity of the solids increases with increasing ni trogen content. The conditions under which synthesis takes place influence the final nitrogen content and the surface structure of the catalysts. Dehy drogenation of isobutane to isobutene of the Pt-AlPON catalyst correlates w ith the basicity of the catalysts. The surface structure of the solids also influences the yield of isobutene. (C) 2000 Academic Press.