Characterization of Surface Structure and Oxidation/Reduction Behaviour of Pd-Pt/Al2O3 Model Catalysts
Artikel i vetenskaplig tidskrift, 2016

Structural and morphological characterisation of bimetallic Pd-Pt/Al2O3 model cat- alysts are performed using X-ray diffraction, X-ray absorption spectroscopy, transmis- sion electron microscopy and CO chemisorption. Further, the catalysts were studied under oxidising and reducing conditions using both X-ray absorption spectroscopy and low-energy ion scattering spectroscopy. For the as-prepared catalysts, the existence of alloyed bimetallic Pd-Pt particles and of (tetragonal) PdO were found for the samples calcined at 800 �C. PdO is present in form of crystals at the surface of the Pd-Pt par- ticles or as isolated PdO crystals on the support oxide. Bimetallic Pd-Pt nanoparticles were only formed on the Pd-Pt catalysts after calcination at 800 �C. The results show that the Pd-Pt nanoparticles undergo reversible changes in surface structure composi- tion and chemical state in response to oxidising or reducing conditions. Under oxidising conditions Pd segregates to the shell and oxidises forming PdO, while under reducing conditions regions with metallic Pd and Pd-Pt alloys were observed at the surface. No bimetallic Pd-Pt nanoparticles were observed for the sample initially calcined at 500 �C, but instead isolated monometallic particles, where small Pt particles are easily oxidised under O2 treatment. In the monometallic catalysts, the Pd is found to be com- pletely oxidised already after calcination and to consist of metallic Pd after reductive treatment.

Författare

Natalia Mihaela Martin

Kompetenscentrum katalys (KCK)

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Johan Nilsson

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Magnus Skoglundh

Kompetenscentrum katalys (KCK)

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Emma Adams

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Xueting Wang

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Peter Velin

Kompetenscentrum katalys (KCK)

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Gudmund Smedler

Agnes Rai

David Thompsett

Hidde Brongersma

Thomas Grehl

Giovanni Agostini

Olivier Mathon

Stefan Carlson

Katarina Norén

Francisco Javier Martinez-Casado

Zdenek Matej

Olivier Balmes

Per-Anders Carlsson

Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 120 28009-28020

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Transport

Energi

Materialvetenskap

Ämneskategorier

Fysikalisk kemi

Kemiska processer

Den kondenserade materiens fysik

DOI

10.1021/acs.jpcc.6b09223