2026-04-13T06:38:00Zhttps://recercat.cat/oai/request

oai:recercat.cat:2072/4890792026-01-12T12:51:59Zcom_2072_300912com_2072_4427col_2072_301309

Dynamic Confinement Approach for High Metal Loading Single-Atom Catalysts Based on Covalent Organic Frameworks Song, Kyung Seob Najafov, Murad González Acosta, José Manuel Ruiz Ferrando, Andrea Pollitt, Stephan Fritz, Patrick W. Ashirov, Timur Piech, Krzysztof Gándara, Felipe Nachtegaal, Maarten López, Núria Coskun, Ali Single-atom catalysts (SACs) offer stable, well-defined active sites by anchoring individual metal atoms on stable organic or inorganic supports, though achieving high metal loadings without clustering or leaching remains a major challenge. Here, we report a synthetic strategy for developing ultra-high metal loading SACs based on palladium polyphthalocyanine covalent organic frameworks (COFs) synthesized via a mixed metal ionothermal approach, which involves the cyclization of tetracyanobenzene and tetracyanopyrazine as precursors in molten salt mixtures of PdCl2/ZnCl2 or PdCl2/ZnCl2/NaCl. This approach effectively combines the formation of crystalline polymeric hosts with metal impregnation in a single step, yielding COFs with atomically distributed Pd ions and metal contents of up to 22.2 wt%. Theoretical simulations reveal that the crystalline framework dynamically confines Pd atoms between different binding sites within the pores, preventing dimerization and ensuring long-term catalyst stability. The synthesized catalysts were evaluated under continuous flow conditions, exhibiting stable performance with yields as high as 90% and maintaining stability over a 24 h time-on-stream under low-conversion conditions. These results establish a new benchmark for SACs and underscore the importance of dynamic confinement approach in achieving high metal loadings on crystalline organic supports. 2026-01-12T11:41:07Z 2026-01-12T11:41:07Z 2026-01-12T11:41:07Z 2026-01-01 info:eu-repo/semantics/article http://hdl.handle.net/2072/489079 https://doi.org/10.1002/anie.202522238 eng NCCR Catalysis (grant number 180544), a National Centre of Competence in Research funded by the Swiss National Science Foundation CERCA Program/Generalitat de Catalunya Severo Ochoa Excellence Accreditation CEX2024-001469-S funded by MCIU/AEI/10.13039/501100011033 PID2024-157556OB-100 J.M. G.-A. acknowledge funding from the Joan Oró Predoctoral Fellowship Programme of the Department of Research and Universities of the Government of Catalonia and the European Social Fund Plus (FSEE+) ref: 2024 FI-1 00437 The authors acknowledge SLS for providing beamtime (MESQUICK proposal: 20230014) at the SuperXAS beamline http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Attribution 4.0 International Wiley RECERCAT (Dipòsit de la Recerca de Catalunya)