Dynamical Observation and Detailed Description of Catalysts under Strong Metal-Support Interaction.
Understanding the structures of catalysts under realistic conditions with atomic precision is crucial to design better materials for challenging transformations. Under reducing conditions, certain reducible supports migrate onto supported metallic particles and create strong metal-support states that drastically change the reactivity of the systems. The details of this process are still unclear and preclude its thorough exploitation. Here, we report an atomic description of a palladium/titania (Pd/TiO2) system by combining state-of-the-art in situ transmission electron microscopy and density functional theory (DFT) calculations with structurally defined materials, in which we visualize the formation of the overlayers at the atomic scale under atmospheric pressure and high temperature. We show that an amorphous reduced titania layer is formed at low temperatures, and that crystallization of the layer into either mono- or bilayer structures is dictated by the reaction environment and predicted by theory. Furthermore, it occurs in combination with a dramatic reshaping of the metallic surface facets.
Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States.|Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
Shuyi
S
Zhang
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.|Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States.
Philipp N
PN
Plessow
Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States.
Joshua J
JJ
Willis
Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States.|Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
Sheng
S
Dai
Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States.|Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
Mingjie
M
Xu
Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States.|Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
George W
GW
Graham
Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States.
Matteo
M
Cargnello
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
Frank
F
Abild-Pedersen
Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States.|Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States.
Xiaoqing
X
Pan
Pd nanoparticles; SMSI; TiO2; in situ microcopy