Structure and catalytic combustion activity of atomically dispersed Pt species at MgO surface

We have investigated the structure of Pt(A)/MgO and PtMo6/MgO catalysts whi ch were prepared from Pt(C5H7O2)(2) and [PtMo6O24](8-) followed by calcinat ion, respectively, and their catalytic activities for the propane + O-2 rea ction. The Pt(A)/MgO and PtMo6/MgO catalysts with atomically dispersed Pt i ons were found to be as active as metallic Pt particles supported on MgO fo r propane combustion. A distorted spinel-like structure around Pt ion embed ded at the MgO surface was proposed for the active Pt species by means of E XAFS. The atomically dispersed Pt structure was reduced with propane at 623 K to form Pt-6 clusters with Pt-O bonding to the MgO support. The Pt clust er chemically attached to the MgO surface was selective for the propane deh ydrogenation. Restructuring of the Pt clusters to the atomically dispersed Pt structure was observed by oxidation with O-2 at 623 K. (C) 1999 Elsevier Science B.V. All rights reserved.