{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,6]],"date-time":"2026-11-06T23:49:11Z","timestamp":1794008951076,"version":"4.8.0"},"reference-count":35,"publisher":"American Chemical Society (ACS)","issue":"18","license":[{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS-2024-00414454"],"award-info":[{"award-number":["RS-2024-00414454"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000015","name":"U.S. Department of Energy","doi-asserted-by":"publisher","award":["DE-SC-0019445"],"award-info":[{"award-number":["DE-SC-0019445"]}],"id":[{"id":"10.13039\/100000015","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Science Foundation (NSF)","award":["2544087"],"award-info":[{"award-number":["2544087"]}]},{"name":"National Science Foundation (NSF)","award":["DMR-1719875"],"award-info":[{"award-number":["DMR-1719875"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,22]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Electrochemical CO2 reduction (CO2RR) offers a promising strategy to convert CO2 into high-value chemicals and fuels. However, probing the mechanism of dynamic catalyst reconstruction remains a longstanding challenge, which calls for operando time-resolved and quantitative spectroscopic methods. Here, we employed operando high-energy-resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) to monitor real-time structural evolution of bimetallic FeCu single-atom catalysts (SACs) on nitrogen-doped carbon (FeCu\u2013N\u2013C) as a model single-atom catalyst for the CO2RR. FeCu\u2013N\u2013C exhibits a 2-fold increase in Faradaic efficiency for CO formation and an order-of-magnitude enhancement in the CO partial current density at the same applied potential, when compared to monometallic Fe SAC (Fe\u2013N\u2013C). To elucidate the origin of this performance enhancement, operando HERFD-XAS was used to directly probe the dynamic evolution of metal oxidation states and coordination environments under operating conditions, revealing a dynamic reconstruction of isolated Fe and Cu single atoms into catalytically active metallic clusters. In contrast, the Fe SAC control remains atomically dispersed over the course of CO2RR. The atomic-scale structural insights are further corroborated by aberration-corrected scanning transmission electron microscopy. These findings shed light on the synergistic role of Cu in modulating the dynamic reconstruction of single-atom Fe sites and provide fundamental insights for the rational design of high-performance single-atom catalysts for CO2 electroreduction.<\/jats:p>","DOI":"10.1021\/acs.chemmater.6c00765","type":"journal-article","created":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T10:50:44Z","timestamp":1788432644000},"page":"9205-9214","source":"Crossref","is-referenced-by-count":3,"title":["Dynamic Evolution\nof Bimetallic Single-Atom Catalysts\nduring Carbon Dioxide Reduction Probed by\n                    <i>Operando<\/i>\n                    X-ray Spectroscopy"],"prefix":"10.1021","volume":"38","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-8750-2560","authenticated-orcid":true,"given":"Jiahong","family":"Jiang","sequence":"first","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2744-5934","authenticated-orcid":true,"given":"Nikolaos","family":"Chalmpes","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9732-935X","authenticated-orcid":true,"given":"Ritwick","family":"Sinha","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0770-6113","authenticated-orcid":true,"given":"Juhyung","family":"Choi","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7332-5274","authenticated-orcid":true,"given":"Iosif","family":"Tantis","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8407-2260","authenticated-orcid":true,"given":"Valenti\u0301n","family":"Briega-Martos","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]},{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sean C.","family":"McInnis","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenqi","family":"Li","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4646-1625","authenticated-orcid":true,"given":"Yong L.","family":"Joo","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emmanuel P.","family":"Giannelis","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0321-3792","authenticated-orcid":true,"given":"Yao","family":"Yang","sequence":"additional","affiliation":[{"name":"Cornell University , , , ,","place":["Ithaca, New York, United States, 14850"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,1]]},"reference":[{"key":"2026092208100768300_cit1","doi-asserted-by":"publisher","first-page":"639","DOI":"10.1038\/s41586-019-1760-8","article-title":"Domino electroreduction\nof CO2 to methanol on a molecular catalyst","volume":"575","author":"Wu","year":"2019","journal-title":"Nature"},{"key":"2026092208100768300_cit2","doi-asserted-by":"publisher","first-page":"262","DOI":"10.1038\/s41586-022-05540-0","article-title":"Operando\nstudies reveal active Cu nanograins for CO2 electroreduction","volume":"614","author":"Yang","year":"2023","journal-title":"Nature"},{"key":"2026092208100768300_cit3","doi-asserted-by":"publisher","DOI":"10.1126\/science.adr3834","article-title":"Acid-humidified CO2 gas input for stable electrochemical\nCO2 reduction\nreaction","volume":"388","author":"Hao","year":"2025","journal-title":"Science"},{"key":"2026092208100768300_cit4","doi-asserted-by":"publisher","first-page":"732","DOI":"10.1038\/s41560-019-0450-y","article-title":"Advances and challenges in understanding\nthe electrocatalytic conversion of carbon dioxide to fuels","volume":"4","author":"Birdja","year":"2019","journal-title":"Nat. Energy"},{"key":"2026092208100768300_cit5","doi-asserted-by":"publisher","first-page":"2854","DOI":"10.1039\/D2CC06406E","article-title":"The synthesis\nof single-atom catalysts for heterogeneous catalysis","volume":"59","author":"Fang","year":"2023","journal-title":"Chem. Commun."},{"key":"2026092208100768300_cit6","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1038\/s41467-018-02819-7","article-title":"Active sites of copper-complex\ncatalytic materials for electrochemical\ncarbon dioxide reduction","volume":"9","author":"Weng","year":"2018","journal-title":"Nat. Commun."},{"key":"2026092208100768300_cit7","doi-asserted-by":"publisher","first-page":"11900","DOI":"10.1021\/acs.chemrev.9b00818","article-title":"Chemical Synthesis of Single Atomic Site Catalysts","volume":"120","author":"Ji","year":"2020","journal-title":"Chem. Rev."},{"key":"2026092208100768300_cit8","doi-asserted-by":"publisher","first-page":"11767","DOI":"10.1021\/acs.chemrev.4c00155","article-title":"Single Atom\nCatalysts Based on Earth-Abundant Metals\nfor Energy-Related Applications","volume":"124","author":"Kment","year":"2024","journal-title":"Chem. Rev."},{"key":"2026092208100768300_cit9","doi-asserted-by":"publisher","first-page":"4352","DOI":"10.1039\/D5CY00565E","article-title":"Promising\nsingle-atom catalysts for\nenvironmental energy material applications: overview and perspectives","volume":"15","author":"Qin","year":"2025","journal-title":"Catal. Sci. Technol."},{"key":"2026092208100768300_cit10","doi-asserted-by":"publisher","first-page":"692","DOI":"10.1039\/d5cc05829e","article-title":"Single-atom\ncatalysts for selective electrochemical\nCO2 reduction to C2 products","volume":"62","author":"Zhao","year":"2026","journal-title":"Chem. Commun."},{"key":"2026092208100768300_cit11","doi-asserted-by":"publisher","first-page":"37808","DOI":"10.1021\/jacs.5c14123","article-title":"Dynamic Evolution from Single-Atom Catalysts to Active Nanograins\nfor CO2 Reduction","volume":"147","author":"Choi","year":"2025","journal-title":"J. Am. Chem. Soc."},{"key":"2026092208100768300_cit12","doi-asserted-by":"publisher","first-page":"75","DOI":"10.1038\/s41929-019-0383-7","article-title":"Cooperative CO2-to-ethanol conversion via enriched intermediates\nat molecule\u2013metal catalyst interfaces","volume":"3","author":"Li","year":"2020","journal-title":"Nat. Catal."},{"key":"2026092208100768300_cit13","doi-asserted-by":"publisher","first-page":"48180","DOI":"10.1021\/jacs.5c16581","article-title":"Assembly of Face Decorated Cuboidal\nCages into Ultraporous Structures with Hierarchical Porosity: Accessing\nMOFs with the Awaited red-a Topology","volume":"147","author":"Froudas","year":"2025","journal-title":"J. Am.\nChem. Soc."},{"key":"2026092208100768300_cit14","doi-asserted-by":"publisher","first-page":"118786","DOI":"10.1016\/j.jece.2025.118786","article-title":"Emergence\nof single\natom catalyst and metallic organic frameworks (MOF) derived photocatalytic\nsystems for CO2 conversion into C1 value added products","volume":"13","author":"Panwar","year":"2025","journal-title":"J. Environ. Chem. Eng."},{"key":"2026092208100768300_cit15","doi-asserted-by":"publisher","first-page":"6199","DOI":"10.1038\/s41467-024-50476-w","article-title":"Metal-organic\nframework derived crystalline nanocarbon\nfor Fenton-like reaction","volume":"15","author":"Lian","year":"2024","journal-title":"Nat. Commun."},{"key":"2026092208100768300_cit16","doi-asserted-by":"publisher","first-page":"1305","DOI":"10.1021\/acs.energyfuels.4c05250","article-title":"Elevating\nWaste Biomass: Supercapacitor Electrode Materials Derived from Spent\nCoffee Grounds","volume":"39","author":"Chalmpes","year":"2025","journal-title":"Energy Fuels"},{"key":"2026092208100768300_cit17","doi-asserted-by":"publisher","first-page":"33491","DOI":"10.1021\/acsnano.4c10531","article-title":"Ultrahigh Surface Area Nanoporous Carbons Synthesized\nvia Hypergolic and Activation Reactions for Enhanced CO2 Capacity and Volumetric Energy Density","volume":"18","author":"Chalmpes","year":"2024","journal-title":"ACS\nNano"},{"key":"2026092208100768300_cit18","doi-asserted-by":"publisher","first-page":"15280","DOI":"10.1021\/acsomega.4c11318","article-title":"Pyrolytic Transformation\nof Zn-TAL Metal\u2013Organic Framework into Hollow Zn\u2013N\u2013C\nSpheres for Improved Oxygen Reduction Reaction Catalysis","volume":"10","author":"Yusibova","year":"2025","journal-title":"ACS Omega"},{"key":"2026092208100768300_cit19","doi-asserted-by":"publisher","first-page":"8829","DOI":"10.1021\/acssuschemeng.5c01382","article-title":"Unraveling the Recent\nAdvancement of Single-Atom Catalysts Derived from Metal\u2013Organic\nFrameworks for Sustainable Electrocatalysis","volume":"13","author":"Hussain","year":"2025","journal-title":"ACS Sustainable Chem. Eng."},{"key":"2026092208100768300_cit20","doi-asserted-by":"publisher","first-page":"21838","DOI":"10.1021\/acsami.4c00911","article-title":"Robust Activity and Stability of P-Doped Fe-Carbon Composites Derived\nfrom MOF for Bromate Reduction","volume":"16","author":"Long","year":"2024","journal-title":"ACS Appl. Mater.\nInterfaces"},{"key":"2026092208100768300_cit21","doi-asserted-by":"publisher","first-page":"14305","DOI":"10.1021\/acscatal.5c01947","article-title":"Nitrogen\nCoordinated Iron on Porous\nCarbon\u2013Titanium Nitride Hybrid: A Non-precious Metal Catalyst\nfor the 4e\u2013 ORR Pathway","volume":"15","author":"Tantis","year":"2025","journal-title":"ACS Catal."},{"key":"2026092208100768300_cit22","doi-asserted-by":"publisher","first-page":"566","DOI":"10.3390\/nano10030566","article-title":"Functional Carbon Materials Derived\nthrough Hypergolic Reactions at Ambient Conditions","volume":"10","author":"Chalmpes","year":"2020","journal-title":"Nanomaterials"},{"key":"2026092208100768300_cit23","doi-asserted-by":"publisher","first-page":"2207","DOI":"10.3390\/molecules25092207","article-title":"Hypergolics in Carbon\nNanomaterials Synthesis: New\nParadigms and Perspectives","volume":"25","author":"Chalmpes","year":"2020","journal-title":"Molecules"},{"key":"2026092208100768300_cit24","doi-asserted-by":"publisher","first-page":"114839","DOI":"10.1016\/j.jece.2024.114839","article-title":"Efficient\nCO2 capture by ZIF-8-derived in-situ nitrogen-doped nanoporous\ncarbon\nwith ultra-high selectivity and stability","volume":"12","author":"Zhang","year":"2024","journal-title":"J.\nEnviron. Chem. Eng."},{"key":"2026092208100768300_cit25","doi-asserted-by":"publisher","first-page":"2307809","DOI":"10.1002\/adma.202307809","article-title":"Reversible Structural Evolution of Metal-Nitrogen-Doped\nCarbon Catalysts During CO2 Electroreduction: An Operando\nX-ray Absorption Spectroscopy Study","volume":"36","author":"Hursa\u0301n","year":"2024","journal-title":"Adv. Mater."},{"key":"2026092208100768300_cit26","doi-asserted-by":"publisher","first-page":"102420","DOI":"10.1016\/j.jcou.2023.102420","article-title":"Cu dopant triggered\nFe-N-C catalysts toward high efficiency electroreduction of CO2 to CO","volume":"70","author":"Zhao","year":"2023","journal-title":"J. CO2 Util."},{"key":"2026092208100768300_cit27","doi-asserted-by":"publisher","first-page":"3958","DOI":"10.1038\/s41467-022-31660-2","article-title":"Subnanometric\nRu clusters\nwith upshifted D band center improve performance for alkaline hydrogen\nevolution reaction","volume":"13","author":"Hu","year":"2022","journal-title":"Nat. Commun."},{"key":"2026092208100768300_cit28","doi-asserted-by":"publisher","first-page":"13060","DOI":"10.1021\/acs.langmuir.4c00804","article-title":"Competition\nbetween Initial CO2 Electroreduction and Hydrogen Evolution\nReaction on Cu Catalysts in Acidic Media: Role of Specifically Adsorbed\nHalide Anions","volume":"40","author":"Ou","year":"2024","journal-title":"Langmuir"},{"key":"2026092208100768300_cit29","doi-asserted-by":"publisher","first-page":"65","DOI":"10.1016\/j.ccr.2004.04.011","article-title":"High resolution 1s core hole X-ray\nspectroscopy in\n3d transition metal complexes\u2500electronic and structural information","volume":"249","author":"Glatzel","year":"2005","journal-title":"Coord. Chem. Rev."},{"key":"2026092208100768300_cit30","doi-asserted-by":"publisher","first-page":"20208","DOI":"10.1021\/jacs.3c08182","article-title":"Operando High-Energy-Resolution X-ray\nSpectroscopy of Evolving Cu Nanoparticle Electrocatalysts for CO2Reduction","volume":"145","author":"Feijoo","year":"2023","journal-title":"J. Am. Chem. Soc."},{"key":"2026092208100768300_cit31","doi-asserted-by":"publisher","first-page":"537","DOI":"10.1107\/S0909049505012719","article-title":"ATHENA ARTEMIS, HEPHAESTUS: data\nanalysis for X-ray\nabsorption spectroscopy using IFEFFIT","volume":"12","author":"Ravel","year":"2005","journal-title":"J. Synchrotron\nRadiat."},{"key":"2026092208100768300_cit32","doi-asserted-by":"publisher","first-page":"3158","DOI":"10.1039\/D3EE00027C","article-title":"Boosting electrochemical methane\nconversion by oxygen evolution reactions on Fe\u2013N\u2013C single\natom catalysts","volume":"16","author":"Kim","year":"2023","journal-title":"Energy Environ. Sci."},{"key":"2026092208100768300_cit33","doi-asserted-by":"publisher","first-page":"2311","DOI":"10.1021\/la991011c","article-title":"Unified Approach\nto Pore Size Characterization of Microporous Carbonaceous Materials\nfrom N2, Ar, and CO2 Adsorption Isotherms","volume":"16","author":"Ravikovitch","year":"2000","journal-title":"Langmuir"},{"key":"2026092208100768300_cit34","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1007\/s10450-014-9606-z","article-title":"Physical adsorption\ncharacterization of nanoporous\nmaterials: progress and challenges","volume":"20","author":"Thommes","year":"2014","journal-title":"Adsorption"},{"key":"2026092208100768300_cit35","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.colsurfb.2013.01.007","article-title":"Experimental\nstudies on the effect of different metallic substrates on marine biofouling","volume":"106","author":"Vedaprakash","year":"2013","journal-title":"Colloids Surf., B"}],"container-title":["Chemistry of Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.chemmater.6c00765","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/cmatex\/article-pdf\/38\/18\/9205\/68112871\/acs.chemmater.6c00765.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/cmatex\/article-pdf\/38\/18\/9205\/68112871\/acs.chemmater.6c00765.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T12:30:22Z","timestamp":1790080222000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/cmatex\/article\/38\/18\/9205\/5396854\/Dynamic-Evolution-of-Bimetallic-Single-Atom"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,1]]},"references-count":35,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9,1]]},"published-print":{"date-parts":[[2026,9,22]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.chemmater.6c00765","relation":{},"ISSN":["0897-4756","1520-5002"],"issn-type":[{"value":"0897-4756","type":"print"},{"value":"1520-5002","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,1]]}}}