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Büchele S, Yakimov A, Collins SM, Ruiz-Ferrando A, Chen Z, Willinger E, Kepaptsoglou DM, Ramasse QM, Müller CR, Safonova OV, López N, Copéret C, Pérez-Ramírez J, Mitchell S. Elucidation of Metal Local Environments in Single-Atom Catalysts Based on Carbon Nitrides. Small 2022; 18:e2202080. [PMID: 35678101 DOI: 10.1002/smll.202202080] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The ability to tailor the properties of metal centers in single-atom heterogeneous catalysts depends on the availability of advanced approaches for characterization of their structure. Except for specific host materials with well-defined metal adsorption sites, determining the local atomic environment remains a crucial challenge, often relying heavily on simulations. This article reports an advanced analysis of platinum atoms stabilized on poly(triazine imide), a nanocrystalline form of carbon nitride. The approach discriminates the distribution of surface coordination sites in the host, the evolution of metal coordination at different stages during the synthesis of the material, and the potential locations of metal atoms within the lattice. Consistent with density functional theory predictions, simultaneous high-resolution imaging in high-angle annular dark field and bright field modes experimentally confirms the preferred localization of platinum in-plane in the corners of the triangular cavities. X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and dynamic nuclear polarization enhanced 15 N nuclear magnetic resonance (DNP-NMR) spectroscopies coupled with density functional theory (DFT) simulations reveal that the predominant metal species comprise Pt(II) bound to three nitrogen atoms and one chlorine atom inside the coordination sites. The findings, which narrow the gap between experimental and theoretical elucidation, contribute to the improved structural understanding and provide a benchmark for exploring the speciation of single-atom catalysts based on carbon nitrides.
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Affiliation(s)
- Simon Büchele
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland
| | - Alexander Yakimov
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland
| | - Sean M Collins
- Bragg Centre for Materials Research, School of Chemical and Process Engineering and School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Andrea Ruiz-Ferrando
- Institute of Chemical Research of Catalonia and Barcelona Institute of Science and Technology, Av. Països Catalans 16, Tarragona, 43007, Spain
| | - Zupeng Chen
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, P. R. China
| | - Elena Willinger
- Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, Zurich, 8092, Switzerland
| | | | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, WA4 4AD, UK
| | - Christoph R Müller
- Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, Zurich, 8092, Switzerland
| | - Olga V Safonova
- Paul Scherrer Institute, Forschungsstrasse 111, Villigen, 5232, Switzerland
| | - Núria López
- Institute of Chemical Research of Catalonia and Barcelona Institute of Science and Technology, Av. Països Catalans 16, Tarragona, 43007, Spain
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland
| | - Javier Pérez-Ramírez
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland
| | - Sharon Mitchell
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland
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