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説明:

Single-atom catalysts are thought to be the pinnacle of catalysis. However, for many reactions, their suitability has yet to be unequivocally proven. Here, we demonstrate why single Pd atoms (PdSA) are not catalytically ideal for generating H2 from formic acid as a H2 carrier. We loaded PdSA on three silica substrates, mesoporous silicas functionalized with thiol, amine, and dithiocarbamate functional groups. The Pd catalytic activity on aminofunctionalized silica (SiO2−NH2/PdSA) was far higher than that of the thiolbased catalysts (SiO2−S−PdSA and SiO2−NHCS2−PdSA), while the single-atom stability of SiO2−NH2/PdSA against aggregation after the first catalytic cycle was the weakest. In this case, Pd aggregation boosted the reaction yield. Our experiments and calculations demonstrate that PdSA in SiO2−NH2/PdSA loosely binds with amine groups. This leads to a limited charge transfer from Pd to the amine groups and causes high aggregability and catalytic activity. According to the density functional calculations, the loose binding between Pd and N causes most of Pd’s 4d electrons in amino-functionalized SiO2 to remain close to the Fermi level and labile for catalysis. However, PdSA chemically binds to the thiol group, resulting in strong hybridization between Pd and S, pulling Pd’s 4d states deeper into the conduction band and away from the Fermi level. Consequently, fewer 4d electrons were available for catalysis.

権利情報:

• In Copyright
  This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.3c18709

キーワード: single-atom catalysis (SAC), Pd nanocluster, silica-supported Pd, Pd DOS, metal−support interaction, catalyst reconstruction, ligand−metal charge transfer

刊行年月日: 2024-02-28

出版者: American Chemical Society (ACS)

掲載誌:

• ACS Applied Materials & Interfaces (ISSN: 19448244) vol. 16 issue. 8 p. 10251-10259

研究助成金:

• HORIZON EUROPE Marie Sklodowska-Curie Actions 120C057
• Japan Society for the Promotion of Science 21H02034
• T?rkiye Bilimsel ve Teknolojik Arastirma Kurumu 120C057

原稿種別: 著者最終稿 (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4438

公開URL: https://doi.org/10.1021/acsami.3c18709

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更新時刻: 2025-01-19 16:31:14 +0900

MDRでの公開時刻: 2025-01-19 16:31:14 +0900