TY - JOUR
T1 - Second-Sphere Effects on Methane Hydroxylation in Cu-Zeolites
AU - Snyder, Benjamin E.R.
AU - Vanelderen, Pieter
AU - Schoonheydt, Robert A.
AU - Sels, Bert F.
AU - Solomon, Edward I.
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/7/25
Y1 - 2018/7/25
N2 - Two [Cu2O]2+ cores have been identified as the active sites of low temperature methane hydroxylation in the zeolite Cu-MOR. These cores have similar geometric and electronic structures, yet different reactivity with CH4: one reacts with a much lower activation enthalpy. In the present study, we couple experimental reactivity and spectroscopy studies to DFT calculations to arrive at structural models of the Cu-MOR active sites. We find that the more reactive core is located in a constricted region of the zeolite lattice. This leads to close van der Waals contact between the substrate and the zeolite lattice in the vicinity of the active site. The resulting enthalpy of substrate adsorption drives the subsequent H atom abstraction step - a manifestation of the "nest" effect seen in hydrocarbon cracking on acid zeolites. This defines a mechanism to tune the reactivity of metal active sites in microporous materials.
AB - Two [Cu2O]2+ cores have been identified as the active sites of low temperature methane hydroxylation in the zeolite Cu-MOR. These cores have similar geometric and electronic structures, yet different reactivity with CH4: one reacts with a much lower activation enthalpy. In the present study, we couple experimental reactivity and spectroscopy studies to DFT calculations to arrive at structural models of the Cu-MOR active sites. We find that the more reactive core is located in a constricted region of the zeolite lattice. This leads to close van der Waals contact between the substrate and the zeolite lattice in the vicinity of the active site. The resulting enthalpy of substrate adsorption drives the subsequent H atom abstraction step - a manifestation of the "nest" effect seen in hydrocarbon cracking on acid zeolites. This defines a mechanism to tune the reactivity of metal active sites in microporous materials.
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U2 - 10.1021/jacs.8b05320
DO - 10.1021/jacs.8b05320
M3 - Article
C2 - 29954176
AN - SCOPUS:85049381605
SN - 0002-7863
VL - 140
SP - 9236
EP - 9243
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 29
ER -