Chemistry of supported palladium nanoparticles during methane oxidation
Journal article, 2015
Time-resolved in situ energy-dispersive X-ray absorption spectroscopy and mass spectrometry are used to correlate changes in chemical state of alumina and ceria supported palladium nanoparticles with changes in activity and selectivity for methane oxidation. Specifically, modulation excitation spectroscopy experiments are carried out by periodically cycling between net-reducing and net-oxidizing reaction conditions. The XANES and EXAFS data show that the palladium nanoparticles are readily bulk oxidized when exposed to oxygen, forming a PdO-like phase, and reduced back to a reduced (metal) phase when oxygen is removed from the feed. The difference between the two support materials is most noticeable at the switches between net-oxidizing and net-reducing reaction conditions. Here, a brief reduction in conversion is observed for the alumina supported catalyst, but for the ceria this reduction in conversion is minor or not observed at all. This difference is attributed to differences in the oxidation kinetics and the oxygen storage capability of ceria.
XAFS
methane
in situ
modulation excitation
homogeneous catalysis
Author
Johan Nilsson
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Per-Anders Carlsson
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Competence Centre for Catalysis (KCK)
Sheedeh Fouladvand
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Natalia Mihaela Martin
Competence Centre for Catalysis (KCK)
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Johan Gustafsson
Lund University
Mark Newton
European Synchrotron Radiation Facility (ESRF)
Edvin Lundgren
Lund University
Henrik Grönbeck
Competence Centre for Catalysis (KCK)
Chalmers, Applied Physics, Chemical Physics
Magnus Skoglundh
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Competence Centre for Catalysis (KCK)
ACS Catalysis
2155-5435 (eISSN)
Vol. 5 4 2481-2489Time-resolved in situ methods for design of catalytic sites within sustainable chemistry
Swedish Research Council (VR) (2013-567), 2013-01-01 -- 2016-12-31.
Unravelling catalytically active sites with X-ray absorption spectroscopy
Swedish Research Council (VR) (2011-5009), 2012-01-01 -- 2015-12-31.
Driving Forces
Sustainable development
Areas of Advance
Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)
Transport
Energy
Materials Science
Subject Categories
Physical Chemistry
Chemical Process Engineering
Atom and Molecular Physics and Optics
Roots
Basic sciences
DOI
10.1021/cs502036d