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How Strain Affects the Reactivity of Surface Metal Oxide Catalysts
Author(s) -
Amakawa Kazuhiko,
Sun Lili,
Guo Chunsheng,
Hävecker Michael,
Kube Pierre,
Wachs Israel E.,
Lwin Soe,
Frenkel Anatoly I.,
Patlolla Anitha,
Hermann Klaus,
Schlögl Robert,
Trunschke Annette
Publication year - 2013
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201306620
Subject(s) - catalysis , reactivity (psychology) , propene , oxide , dehydrogenation , silanol , xanes , molybdenum , raman spectroscopy , vanadium oxide , metal , propane , materials science , inorganic chemistry , monolayer , transition metal , chemistry , spectroscopy , nanotechnology , organic chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics , optics
Highly dispersed molybdenum oxide supported on mesoporous silica SBA‐15 has been prepared by anion exchange resulting in a series of catalysts with changing Mo densities (0.2–2.5 Mo atoms nm −2 ). X‐ray absorption, UV/Vis, Raman, and IR spectroscopy indicate that doubly anchored tetrahedral dioxo MoO 4 units are the major surface species at all loadings. Higher reducibility at loadings close to the monolayer measured by temperature‐programmed reduction and a steep increase in the catalytic activity observed in metathesis of propene and oxidative dehydrogenation of propane at 8 % of Mo loading are attributed to frustration of Mo oxide surface species and lateral interactions. Based on DFT calculations, NEXAFS spectra at the O‐K‐edge at high Mo loadings are explained by distorted MoO 4 complexes. Limited availability of anchor silanol groups at high loadings forces the MoO 4 groups to form more strained configurations. The occurrence of strain is linked to the increase in reactivity.