Shape Changes of Supported Rh Nanoparticles During Oxidation and Reduction Cycles
P. Nolte,1
A. Stierle,1*
N. Y. Jin-Phillipp,1
N. Kasper,1
T. U. Schulli,2
H. Dosch1
The microscopic insight into how and why catalytically active
nanoparticles change their shape during oxidation and reduction
reactions is a pivotal challenge in the fundamental understanding
of heterogeneous catalysis. We report an oxygen-induced shape
transformation of rhodium nanoparticles on magnesium oxide (001)
substrates that is lifted upon carbon monoxide exposure at 600
kelvin. A Wulff analysis of high-resolution in situ x-ray diffraction,
combined with transmission electron microscopy, shows that this
phenomenon is driven by the formation of a oxygen–rhodium–oxygen
surface oxide at the rhodium nanofacets. This experimental access
into the behavior of such nanoparticles during a catalytic cycle
is useful for the development of improved heterogeneous catalysts.
2 Institut Nanosciences et Cryogénie/Service de Physique des Matériaux et des Microstructures, Commissariat à l'Energie Atomique, Grenoble, 38054 Grenoble Cedex 09, France.
* To whom correspondence should be addressed. E-mail: stierle{at}mf.mpg.de
