Study of methane oxidation over alumina supported Pd-Pt catalysts using operando DRIFTS/MS and in situ XAS techniques
Artikel i vetenskaplig tidskrift, 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.

Författare

Natalia Mihaela Martin

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Johan Nilsson

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Magnus Skoglundh

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Emma Adams

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Xueting Wang

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (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-laboratoriet

Katarina Norén

Max IV-laboratoriet

Per-Anders Carlsson

Kompetenscentrum katalys (KCK)

Per-Anders Carlsson Group

Catalysis, Structure & Reactivity

Vol. 3 24-32

Grundläggande studie av vattens inverkan på oxidationskatalysatorer för biogasapplikationer

Energimyndigheten, 2015-04-01 -- 2019-03-31.

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Transport

Energi

Materialvetenskap

Ämneskategorier

Fysikalisk kemi

Övrig annan teknik

Kemiska processer

Den kondenserade materiens fysik

DOI

10.1080/2055074X.2017.1281717

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Senast uppdaterat

2018-10-26