Abstract
In this work, one-step conversion of methane to methanol using molecular oxygen as the oxidant in the presence of CO in aqueous solutions on copper or palladium promoted Ir-ZSM-5 catalyst is first reported. The addition of a second metal to Ir-ZSM-5 promotes the catalyst activity, while product selectivity can be tuned either to methanol on IrCu-ZSM-5 or to formic acid exclusively on IrPd-ZSM-5. Most effective is the combination of the three metal species together. Approximately 1200 μmol/gcat methanol, or ∼23.4 mol of methanol per mol of Ir, are formed on the IrCuPd trimetallic system (methanol selectivity ∼80 %) at 150 °C in 1 h. Our results also demonstrate that atomically dispersed Ir(I)(CO)2 species formed in the presence of CO can activate the C–H bond of methane to methyl species at temperatures below 150 °C. The good stability in cyclic operation is an additional attribute, rendering this type of catalyst a “front-runner” in future catalyst development for direct methane-to-liquid oxygenates.
Original language | English |
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Article number | 120124 |
Journal | Applied Catalysis B: Environmental |
Volume | 292 |
DOIs | |
State | Published - Sep 5 2021 |
Funding
The financial support of this work by the U. S. Department of Energy , DOE/ARPA-e grant# DE-AR0000433 , under subcontract from MIT, is gratefully acknowledged. Use of the Advanced Photon Source at Argonne National Laboratory for XAS experiments was supported by the U. S. DOE , Office of Science , Office of Basic Energy Sciences , under Contract No. DE-AC02-06CH11357. Microscopy experiments at Oak Ridge National Laboratory were supported by the U. S. DOE, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, Propulsion Materials Program. The authors also thank Dr. Adam S. Hoffman and Dr. Simon R. Bare at SLAC National Accelerator Laboratory for assisting with the XAS study and analysis.
Funders | Funder number |
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U. S. DOE | |
U.S. Department of Energy | DE-AR0000433 |
Office of Science | |
Office of Energy Efficiency and Renewable Energy | |
Basic Energy Sciences | DE-AC02-06CH11357 |
Massachusetts Institute of Technology |
Keywords
- C–H bond activation
- Methane
- Methanol
- Single-atom catalysis