TY - JOUR
T1 - Support-dependent Performance of Size-selected Subnanometer Cobalt Cluster-based Catalysts in the Dehydrogenation of Cyclohexene
AU - Lee, S.
AU - Di Vece, M.
AU - Lee, B.
AU - Seifert, S.
AU - Winans, R.E.
AU - Vajda, S.
PY - 2013
Y1 - 2013
N2 - The evolution of the chemical state and change in the morphology
of subnanometer cobalt clusters during the dehydrogenation
of cyclohexene was investigated in terms of metalsupport
interactions. The model catalyst systems were prepared
by deposition of size selected subnanometer Co27 4
clusters on various amorphous metal oxide supports (Al2O3,
ZnO, and MgO), as well as on a carbon-based support
(UNCD=ultrananocrystaline diamond). The reactivity, oxidation
state, and sintering resistance of the clusters were monitored
by temperature programmed reaction (TPRx), in situ grazing incidence
X-ray absorption spectroscopy (GIXAS), and grazing incidence
small angle X-ray scattering (GISAXS), respectively. The
reactivity and selectivity of cobalt clusters show strong dependency
on the support used, with clusters supported on
UNCD possessing the highest activity at 3008C. The evolution
of the oxidation state of metal cluster during the reaction reveals
that metal-support interaction plays a key role in performance
of the subnanometer catalyst. A reversible assembly of
clusters into a nanostructure which evolves with reaction temperature
was observed on the MgO support.
AB - The evolution of the chemical state and change in the morphology
of subnanometer cobalt clusters during the dehydrogenation
of cyclohexene was investigated in terms of metalsupport
interactions. The model catalyst systems were prepared
by deposition of size selected subnanometer Co27 4
clusters on various amorphous metal oxide supports (Al2O3,
ZnO, and MgO), as well as on a carbon-based support
(UNCD=ultrananocrystaline diamond). The reactivity, oxidation
state, and sintering resistance of the clusters were monitored
by temperature programmed reaction (TPRx), in situ grazing incidence
X-ray absorption spectroscopy (GIXAS), and grazing incidence
small angle X-ray scattering (GISAXS), respectively. The
reactivity and selectivity of cobalt clusters show strong dependency
on the support used, with clusters supported on
UNCD possessing the highest activity at 3008C. The evolution
of the oxidation state of metal cluster during the reaction reveals
that metal-support interaction plays a key role in performance
of the subnanometer catalyst. A reversible assembly of
clusters into a nanostructure which evolves with reaction temperature
was observed on the MgO support.
U2 - 10.1002/cctc.201200294
DO - 10.1002/cctc.201200294
M3 - Article
SN - 1867-3880
VL - 4
SP - 1632
EP - 1637
JO - ChemCatChem
JF - ChemCatChem
ER -