title: The structure-function relationship for alumina supported platinum during the formation of ammonia from nitrogen oxide and hydrogen in the presence of oxygen.
abstract: We study the structure-function relationship of alumina supported platinum during the formation of ammonia from nitrogen oxide and dihydrogen by employing in situ X-ray absorption and Fourier transform infrared spectroscopy. Particular focus has been directed towards the effect of oxygen on the reaction as a model system for emerging technologies for passive selective catalytic reduction of nitrogen oxides. The suppressed formation of ammonia observed as the feed becomes net-oxidizing is accompanied by a considerable increase in the oxidation state of platinum as well as the formation of surface nitrates and the loss of NH-containing surface species. In the presence of (excess) oxygen, the ammonia formation is proposed to be limited by weak interaction between nitrogen oxide and the oxidized platinum surface. This leads to a slow dissociation rate of nitrogen oxide and thus low abundance of the atomic nitrogen surface species that can react with the adsorbed hydrogen species. In this case the consumption of hydrogen through the competing water formation reaction and decomposition/oxidation of ammonia are of less importance for the net ammonia formation.
authors.affiliation: Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden. emma.adams@chalmers.se.
authors.forename: Emma Catherine
authors.initials: EC
authors.lastname: Adams
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Lindsay Richard
authors.initials: LR
authors.lastname: Merte
authors.affiliation: Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden. emma.adams@chalmers.se.
authors.forename: Anders
authors.initials: A
authors.lastname: Hellman
authors.affiliation: Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden. emma.adams@chalmers.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Skoglundh
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Gustafson
authors.affiliation: Haldor Topsøe A/S, P.O Box 213, DK-2800 Lyngby, Denmark.
authors.forename: Eva Charlotte
authors.initials: EC
authors.lastname: Bendixen
authors.affiliation: Haldor Topsøe A/S, P.O Box 213, DK-2800 Lyngby, Denmark.
authors.forename: Pär
authors.initials: P
authors.lastname: Gabrielsson
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Florian
authors.initials: F
authors.lastname: Bertram
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Evertsson
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Chu
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Carlson
authors.affiliation: Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden. emma.adams@chalmers.se.
authors.forename: Per-Anders
authors.initials: PA
authors.lastname: Carlsson