(157c) The Active Site and Mechanism for Catalytic Hydrogenation on Metal Cation Catalysts Supported on Nu-1000: Insights from Experiments and Microkinetic Modeling
AIChE Spring Meeting and Global Congress on Process Safety
2022
2022 Spring Meeting and 18th Global Congress on Process Safety Proceedings
Fuels and Petrochemicals Division - See Also Topicals 4, 6, and 7
Advances in Catalysis
Wednesday, April 13, 2022 - 10:45am to 11:15am
The mechanism of ethene hydrogenation to ethane on six dicationic 3d transition metal catalysts is
investigated. Specifically, a combination of density functional theory (DFT), microkinetic modeling, and high
throughput reactor experiments is used to interrogate the active sites and mechanisms for Mn@NU-1000,
Fe@NU-1000, Co@NU-1000, Ni@NU-1000, Cu@NU-1000, and Zn@NU-1000 catalysts, where NU-1000 is
a metal–organic framework (MOF) capable of supporting metal cation catalysts. The combination of
experiments and simulations suggests that the reaction mechanism is influenced by the electron
configuration and spin state of the metal cations as well as the amount of hydrogen that is adsorbed.
Specifically, Ni@NU-1000, Cu@NU-1000, and Zn@NU-1000, which have more electrons in their d shells
and operate in lower spin states, utilize a metal hydride active site and follow a mechanism where the
metal cation binds with one or more species at all steps, whereas Mn@NU-1000, Fe@NU-1000, and
Co@NU-1000, which have fewer electrons in their d shells and operate in higher spin states, utilize a bare
metal cation active site and follow a mechanism where the number of species that bind to the metal cation
is minimized. Instead of binding with the metal cation, catalytic species bind with oxo ligands from the NU-
1000 support, as this enables more facile H2 adsorption. The results reveal opportunities for tuning activity
and selectivity for hydrogenation on metal cation catalysts by tuning the properties that influence hydrogen
content and spin, including the metal cations themselves, the ligands, the binding environments and
supports, and/or the gas phase partial pressures.
investigated. Specifically, a combination of density functional theory (DFT), microkinetic modeling, and high
throughput reactor experiments is used to interrogate the active sites and mechanisms for Mn@NU-1000,
Fe@NU-1000, Co@NU-1000, Ni@NU-1000, Cu@NU-1000, and Zn@NU-1000 catalysts, where NU-1000 is
a metal–organic framework (MOF) capable of supporting metal cation catalysts. The combination of
experiments and simulations suggests that the reaction mechanism is influenced by the electron
configuration and spin state of the metal cations as well as the amount of hydrogen that is adsorbed.
Specifically, Ni@NU-1000, Cu@NU-1000, and Zn@NU-1000, which have more electrons in their d shells
and operate in lower spin states, utilize a metal hydride active site and follow a mechanism where the
metal cation binds with one or more species at all steps, whereas Mn@NU-1000, Fe@NU-1000, and
Co@NU-1000, which have fewer electrons in their d shells and operate in higher spin states, utilize a bare
metal cation active site and follow a mechanism where the number of species that bind to the metal cation
is minimized. Instead of binding with the metal cation, catalytic species bind with oxo ligands from the NU-
1000 support, as this enables more facile H2 adsorption. The results reveal opportunities for tuning activity
and selectivity for hydrogenation on metal cation catalysts by tuning the properties that influence hydrogen
content and spin, including the metal cations themselves, the ligands, the binding environments and
supports, and/or the gas phase partial pressures.