Characterization of Surface Structure and Oxidation/Reduction Behaviour of Pd-Pt/Al2O3 Model Catalysts
Journal article, 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.
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
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Competence Centre for Catalysis (KCK)
Peter Velin
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Competence Centre for Catalysis (KCK)
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
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Journal of Physical Chemistry C
1932-7447 (ISSN) 1932-7455 (eISSN)
Vol. 120 49 28009-28020Fundamental studies on the influence of water on oxidation catalysts for biogas applications
Swedish Energy Agency (P40274-1), 2015-04-01 -- 2019-03-31.
Time-resolved in situ methods for design of catalytic sites within sustainable chemistry
Swedish Research Council (VR) (2013-567), 2013-01-01 -- 2016-12-31.
Driving Forces
Sustainable development
Areas of Advance
Nanoscience and Nanotechnology
Transport
Energy
Materials Science
Subject Categories (SSIF 2011)
Physical Chemistry
Chemical Process Engineering
Condensed Matter Physics
Infrastructure
Chalmers Materials Analysis Laboratory
DOI
10.1021/acs.jpcc.6b09223