Abstract
With heterogeneous catalysts, chemical promotion takes place at their surfaces. Even in the case of single-atom alloys, where small quantities of a reactive metal are dispersed within the main host, it is assumed that both elements are exposed and available to bond with the reactants. Here, we show, on the basis of in situ X-ray absorption spectroscopy data, that in alloy catalysts made from Pt highly diluted in Cu the Pt atoms are located at the inner interface between the metal nanoparticles and the silica support instead. Kinetic experiments indicated that these catalysts still display better selectivity for the hydrogenation of unsaturated aldehydes to unsaturated alcohols than the pure metals. Density functional theory calculations corroborated the stability of Pt at the metal-support interface and explained the catalytic performance as being due to a remote lowering of the activation barrier for the dissociation of H2 at Cu sites by the internal Pt atoms.
| Original language | English |
|---|---|
| Pages (from-to) | 7157-7165 |
| Number of pages | 9 |
| Journal | ACS Catalysis |
| Volume | 14 |
| Issue number | 9 |
| DOIs | |
| State | Published - May 3 2024 |
Funding
Funding for this project was provided by the U.S. National Science Foundation, Division of Chemistry, Award No. NSF-CHE1953843. A.I.F. acknowledges support from the U.S. National Science Foundation, Division of Chemistry, Award No. NSF CHE 2102299. The DFT computational work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Catalysis Science Program (D.-e.J.) and by the Fundamental Research Funds for the Central Universities of China (DUT22LAB601, T.W.). This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Additional resources at Argonne were provided by the Canadian Light Source and its funding partners. We thank Dr. Mahalingam Balasubramanian for his assistance in the XAS data acquisition and Dr. Simon Bare for helpful discussions. We also appreciate Profs. Charles Sykes, Michail Stamatakis, and John Kitchin willingness to provide us with the original data for their DOS calculations of the Pt/Cu(111) surface ( Figure S6 ).
Keywords
- X-ray absorption spectroscopy (XAS, XANES, EXAFS)
- density functional theory (DFT)
- diffusion
- hydrogenation catalysis
- in situ studies
- infrared absorption spectroscopy (IR)
- segregation
- single-atom alloy (SAA) catalysts