Study of methane oxidation over alumina supported Pd-Pt catalysts using operando DRIFTS/MS and in situ XAS techniques
Journal article, 2017
Methane oxidation over Pd–Pt/Al2O3 model catalysts calcined at three different conditions is investigated using operando diffuse reflectance infrared Fourier transform spectroscopy and mass spectrometry, and in situ X-ray absorption spectroscopy while cycling the feed gas stoichiometry between lean (net-oxidising) and rich (net-reducing) conditions. When calcined in air, alloy Pd–Pt nanoparticles are present only on catalysts subjected to elevated temperature (800 ◦C) whereas calcination at lower temperature (500◦C) leads to segregated Pt and Pd nanoparticles on the support. Here, we show that the alloy Pd–Pt nanoparticles undergo reversible changes in surface structure and composition during transient methane oxidation exposing a PdO surface during lean conditions and a metallic Pd–Pt surface (Pd enriched) under rich conditions. Alloyed particles seem more active for methane oxidation than their monometallic counterparts and, furthermore, an increased activity for methane oxidation is clearly observed under lean conditions when PdO has developed on the surface, analogous to monometallic Pd catalysts. Upon introducing rich conditions, partial oxidation of methane dominates over total oxidation forming adsorbed carbonyls on the noble metal particles. The carbonyl spectra for the three samples show clear differences originating from different surfaces exposed by alloyed vs. non-alloyed particles. The kinetics of the noble metal oxidation and reduction processes as well as carbonyl formation during transient methane oxidation are discussed.
methane oxidation
alloy nanoparticles
platinum
palladium
bimetallic catalyst
XAS
Operando spectroscopy
DRIFTS
Author
Natalia Mihaela Martin
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Johan Nilsson
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Magnus Skoglundh
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Competence Centre for Catalysis (KCK)
Emma Adams
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Xueting Wang
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Gudmund Smedler
Johnson Matthey AB
Agnes Raj
Johnson Matthey
David Thompsett
Johnson Matthey
Giovanni Agostini
European Synchrotron Radiation Facility (ESRF)
Stefan Carlson
Lund University
MAX IV Laboratory
Katarina Norén
MAX IV Laboratory
Lund University
Per-Anders Carlsson
Per-Anders Carlsson Group
Competence Centre for Catalysis (KCK)
Catalysis, Structure and Reactivity
20550758 (eISSN)
Vol. 3 1-2 24-32Fundamental studies on the influence of water on oxidation catalysts for biogas applications
Swedish Energy Agency (P40274-1), 2015-04-01 -- 2019-03-31.
Driving Forces
Sustainable development
Areas of Advance
Nanoscience and Nanotechnology
Transport
Energy
Materials Science
Subject Categories
Physical Chemistry
Other Engineering and Technologies not elsewhere specified
Chemical Process Engineering
Condensed Matter Physics
DOI
10.1080/2055074X.2017.1281717