Design of Dilute Palladium–Indium Alloy Catalysts for the Selective Hydrogenation of CO₂ to Methanol
Creators
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1.
University of California, Los Angeles
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2.
Tufts University
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3.
California Institute of Technology
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4.
Saudi Arabia Basic Industries (Saudi Arabia)
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5.
Purdue University West Lafayette
Abstract
Adding small amounts of a more reactive dopant metal to a more selective host metal is a well-known strategy for promoting the catalytic reactivity of the latter without sacrificing its selectivity. While substantial attention has been given to coinage metal hosts for activating individual C–H or O–H bonds, less attention has been given to more exotic metals, such as indium, which is highly selective in the complex hydrogenation of CO2 to methanol. Herein, we describe the synthesis and properties of Pd–In alloys containing Pd in various states of aggregation (isolated atom, small clusters, and extended clusters) assessed through various characterization methods. These materials exhibit unique catalytic behaviors, with Pd promoting both the reaction rate and methanol selectivity in all cases, though its efficacy is highest when Pd is present in small clusters. The inefficiency of high Pd loadings is due in part to losses in Pd accessibility, while the importance of aggregated vs isolated Pd is theorized to result from accelerated H2 activation. Methods used to synthesize more conventional dilute-limit and single-atom alloy catalysts can, therefore, be extended to non-coinage metal hosts to promote and control more complex chemistries, though the roles of ensemble size may greatly differ.
Copyright and License (English)
© 2023 American Chemical Society.
Acknowledgement (English)
Authors acknowledge Dr. Eli Stavitski for assistance with XAS data collection and Georgios Giannakakis for assistance in XAS data collection as well as useful conversations regarding interpretations of various data. A.M.A. acknowledges Sabic T&I for sponsoring his graduate studies. F.H.A. acknowledges Aramco R&D for funding his graduate studies.
Funding (English)
This work was financially supported by Saudi Basic Industries Corporation. J.T.M. was partially funded by the National Science Foundation under Cooperative Agreement No. EEC-1647722. The XAS experiments of this research used beamline 8-ID (ISS) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. E.C.H.S. thanks the DOE/BES Catalysis Science Program for support under grant #DE-SC0021196. N.M.E thanks Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences supported under award #DE-SC0012573.
Contributions (English)
The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.
Data Availability (English)
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Additional characterizations (HRTEM, STEM, EDX mapping image, XRD patterns, XPS, and XAS), stability test, ICP, and XAS fitting data (PDF)
Conflict of Interest (English)
The authors declare no competing financial interest.
Files
cs3c01861_si_001.pdf
Additional details
Identifiers
- ISSN
- 2155-5435
Funding
- Saudi Arabia Basic Industries (Saudi Arabia)
- National Science Foundation
- EEC-1647722
- United States Department of Energy
- DE-SC0012704
- United States Department of Energy
- DE-SC0021196
- United States Department of Energy
- DE-SC0012573