Methane oxidation over alumina supported platinum investigated by time-resolved in situ XANES spectroscopy
Journal article, 2007

In situ time-resolved X-ray absorption spectroscopy and mass spectrometry were used to correlate changes in catalyst surface composition with catalytic activity for methane oxidation over alumina supported Pt. Different transient experiments (i.e., pulsing of oxygen or hydrogen to an otherwise constant gas composition) were performed to study the methane oxidation kinetics. Changes in the surface O/Pt ratio were monitored by the introduction of a new analysis method of the white line area corresponding to the Pt L-III-edge XANES spectra. The relevance of the method was confirmed by first-principles calculations demonstrating how hydrogen and oxygen adsorbates modify the electronic structure of Pt. The experimental results show that during the gas-phase transients, the surface O/Pt ratio changes, which in turn affects the methane oxidation rate. Activity maxima are observed for an intermediate surface O/Pt ratio. An oxygen-rich surface seems to hinder the dissociative adsorption of methane, leading to low methane oxidation activity at oxygen excess.

transient methods

platinum oxide

dissociative adsorption

Pt

heterogeneous catalysis

CH4

X-ray absorption spectroscopy

Pt/Al2O3

Author

Elin Becker

Competence Centre for Catalysis (KCK)

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Per-Anders Carlsson

Chalmers, Chemical and Biological Engineering

Competence Centre for Catalysis (KCK)

Henrik Grönbeck

Chalmers, Applied Physics, Chemical Physics

Competence Centre for Catalysis (KCK)

Magnus Skoglundh

Competence Centre for Catalysis (KCK)

Chalmers, Chemical and Biological Engineering

Journal of Catalysis

0021-9517 (ISSN) 1090-2694 (eISSN)

Vol. 252 1 11-17

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Transport

Energy

Materials Science

Subject Categories

Physical Chemistry

Chemical Engineering

DOI

10.1016/j.jcat.2007.09.004

More information

Created

10/6/2017