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.

Author

Natalia Mihaela Martin

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Johan Nilsson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Magnus Skoglundh

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Emma Adams

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Xueting Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Gudmund Smedler

Johnson Matthey AB

Agnes Raj

Johnson Matthey

David Thompsett

Johnson Matthey

Giovanni Agostini

European Synchrotron Radiation Facility (ESRF)

Stefan Carlson

MAX IV Laboratory

Katarina Norén

MAX IV Laboratory

Per-Anders Carlsson

Competence Centre for Catalysis (KCK)

Per-Anders Carlsson Group

Catalysis, Structure & Reactivity

Vol. 3 24-32

Fundamental studies on the influence of water on oxidation catalysts for biogas applications

Swedish Energy Agency, 2015-04-01 -- 2019-03-31.

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

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

More information

Latest update

10/26/2018