{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T09:44:45Z","timestamp":1791798285543,"version":"4.3.4"},"reference-count":44,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Small"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>High\u2010entropy catalysts (HECs), including high\u2010entropy alloys and high\u2010entropy oxides, have emerged as a transformative class of catalytic materials owing to their exceptional compositional flexibility and entropy\u2010stabilized structures. Unlike conventional catalysts, HECs possess a broad distribution of atomic configurations of surface\u2010active sites that enable simultaneous modulation of reactants\u2019\/intermediates\u2019 adsorption and stabilization energetics, charge transfer, and reaction pathways. Such characteristics provide unique opportunities to overcome long\u2010standing activity\u2010selectivity\u2010stability trade\u2010offs in heterogeneous catalysis. Nevertheless, the extreme compositional complexity of HECs also creates major challenges in identifying the true catalytic active sites and elucidating the underlying reaction mechanisms. This review provides a perspective on how metal active\u2010site engineering in HECs, including strain, ensemble effects, defect engineering, and dynamic surface reconstruction, regulates adsorption configurations, intermediate evolution, proton\u2010coupled electron transfer, and catalytic pathway selectivity. By addressing knowledge gaps in the structure\u2010activity relationship of high\u2010entropy catalysts, this review aims to open a potential avenue for the translation of HEAs into practical implementations for a sustainable energy and environmental future.<\/jats:p>","DOI":"10.1002\/smll.76239","type":"journal-article","created":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T08:45:38Z","timestamp":1791794738000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Metal Active\u2010Site Engineering in High\u2010Entropy Catalysts for Catalytic Applications"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1597-6722","authenticated-orcid":false,"given":"Nguyen Quoc","family":"Thang","sequence":"first","affiliation":[{"name":"Advanced Materials and Applications Research Group HUTECH University  Ho Chi Minh City Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dang Manh","family":"Phuc","sequence":"additional","affiliation":[{"name":"Department of Engineering and System Science National Tsing Hua University  Hsinchu Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8697-7095","authenticated-orcid":false,"given":"Pham","family":"Van Viet","sequence":"additional","affiliation":[{"name":"Advanced Materials and Applications Research Group HUTECH University  Ho Chi Minh City Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,12]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"crossref","first-page":"6600","DOI":"10.1002\/anie.200901193","article-title":"Wilhelm Ostwald: Founder of Physical Chemistry and Nobel Laureate 1909","volume":"48","author":"Ertl G.","year":"2009","journal-title":"Angewandte Chemie International Edition"},{"key":"e_1_2_6_3_1","doi-asserted-by":"crossref","DOI":"10.1002\/adfm.202423751","article-title":"Regulating COOH Intermediate via Rationally Constructed Surface\u2010Active Sites of Bi2WO6 for Solar\u2010Driven CO2 \u2010to\u2010CO Production","volume":"35","author":"Thang N. Q.","year":"2025","journal-title":"Advanced Functional Materials"},{"key":"e_1_2_6_4_1","doi-asserted-by":"crossref","DOI":"10.1002\/smll.202400724","article-title":"Constructing B\u2500N\u2500P Bonds in Ultrathin Holey g\u2010C3N4 for Regulating the Local Chemical Environment in Photocatalytic CO2 Reduction to CO","volume":"20","author":"Hussien M. K.","year":"2024","journal-title":"Small"},{"key":"e_1_2_6_5_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.201807001","article-title":"Enhancing Electrocatalytic Water Splitting by Strain Engineering","volume":"31","author":"You B.","year":"2019","journal-title":"Advanced Materials"},{"key":"e_1_2_6_6_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.ccr.2024.216226","article-title":"Advancements in MXene\u2010Based Frameworks Towards Photocatalytic Hydrogen Production, Carbon Dioxide Reduction and Pollutant Degradation: Current Challenges and Future Prospects","volume":"523","author":"Ajmal Z.","year":"2025","journal-title":"Coordination Chemistry Reviews"},{"key":"e_1_2_6_7_1","doi-asserted-by":"crossref","first-page":"4506","DOI":"10.1021\/acsanm.2c00741","article-title":"S\u2010Scheme \u03b1\u2010Fe2O3\/g\u2010C3N4 Nanocomposites as Heterojunction Photocatalysts for Antibiotic Degradation","volume":"5","author":"Pham V. V.","year":"2022","journal-title":"ACS Applied Nano Materials"},{"key":"e_1_2_6_8_1","doi-asserted-by":"crossref","first-page":"2380","DOI":"10.1039\/D4NA00035H","article-title":"Visible Light Photocatalytic NO x Removal With Suppressed Poisonous NO2 Byproduct Generation Over Simply Synthesized Triangular Silver Nanoparticles Coupled With Tin Dioxide","volume":"6","author":"Pham V. V.","year":"2024","journal-title":"Nanoscale Advances"},{"key":"e_1_2_6_9_1","doi-asserted-by":"crossref","first-page":"2371","DOI":"10.1021\/acs.chemrev.4c00618","article-title":"Interfacial Catalysis at Atomic Level","volume":"125","author":"Peng M.","year":"2025","journal-title":"Chemical Reviews"},{"key":"e_1_2_6_10_1","doi-asserted-by":"crossref","DOI":"10.1002\/smll.202510920","article-title":"Beyond C1 Products: How Single\u2010Atom Catalysts Contribute to Solar\u2010Driven CO2 Reduction into C2+ Hydrocarbons","volume":"22","author":"Thang N. Q.","year":"2026","journal-title":"Small"},{"key":"e_1_2_6_11_1","doi-asserted-by":"crossref","DOI":"10.1002\/smll.202310677","article-title":"Advances in Defect Engineering of Metal Oxides for Photocatalytic CO2 Reduction","volume":"21","author":"Zhong K.","year":"2025","journal-title":"Small"},{"key":"e_1_2_6_12_1","doi-asserted-by":"crossref","first-page":"5859","DOI":"10.1021\/acs.chemrev.2c00356","article-title":"Catalysis of Alloys: Classification, Principles, and Design for a Variety of Materials and Reactions","volume":"123","author":"Nakaya Y.","year":"2023","journal-title":"Chemical Reviews"},{"key":"e_1_2_6_13_1","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/j.msea.2003.10.257","article-title":"Microstructural Development in Equiatomic Multicomponent Alloys","volume":"375","author":"Cantor B.","year":"2004","journal-title":"Materials Science and Engineering: A"},{"key":"e_1_2_6_14_1","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1002\/adem.200300567","article-title":"Nanostructured High\u2010Entropy Alloys With Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes","volume":"6","author":"Yeh J. W.","year":"2004","journal-title":"Advanced Engineering Materials"},{"key":"e_1_2_6_15_1","doi-asserted-by":"crossref","DOI":"10.1002\/adem.202000466","article-title":"Phase Selection, Lattice Distortions, and Mechanical Properties in High\u2010Entropy Alloys","volume":"22","author":"Nutor R. K.","year":"2020","journal-title":"Advanced Engineering Materials"},{"key":"e_1_2_6_16_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202305453","article-title":"Multifunctional High Entropy Alloys Enabled by Severe Lattice Distortion","volume":"36","author":"Wang H.","year":"2024","journal-title":"Advanced Materials"},{"key":"e_1_2_6_17_1","doi-asserted-by":"crossref","first-page":"11280","DOI":"10.1021\/acscatal.0c03617","article-title":"High\u2010Entropy Alloys as a Platform for Catalysis: Progress, Challenges, and Opportunities","volume":"10","author":"Xin Y.","year":"2020","journal-title":"ACS Catalysis"},{"key":"e_1_2_6_18_1","article-title":"Navigating Complexity to Design Nanostructured High\u2010Entropy Alloy Catalysts","volume":"16","author":"Zheng X.","year":"2025","journal-title":"Advanced Energy Materials"},{"key":"e_1_2_6_19_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.cej.2022.138659","article-title":"High\u2010Entropy Oxides for Catalysis: A Diamond in the Rough","volume":"451","author":"Pan Y.","year":"2023","journal-title":"Chemical Engineering Journal"},{"key":"e_1_2_6_20_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.jcat.2025.116114","article-title":"Design Targeted High Entropy Sulfides Catalysts for OER by Theoretical Predictions","volume":"447","author":"Zhang M.","year":"2025","journal-title":"Journal of Catalysis"},{"key":"e_1_2_6_21_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202410295","article-title":"Amorphous High\u2010Entropy Phosphide Nanosheets With Multi\u2010Atom Catalytic Sites for Efficient Oxygen Evolution","volume":"37","author":"Li X.","year":"2025","journal-title":"Advanced Materials"},{"key":"e_1_2_6_22_1","doi-asserted-by":"crossref","first-page":"12808","DOI":"10.1039\/D4TA09220A","article-title":"High\u2010Entropy Compounds for Photo(electro)catalysis: Diverse Materials and Applications","volume":"13","author":"Shan B.\u2010F.","year":"2025","journal-title":"Journal of Materials Chemistry A"},{"key":"e_1_2_6_23_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202002853","article-title":"Continuous Synthesis of Hollow High\u2010Entropy Nanoparticles for Energy and Catalysis Applications","volume":"32","author":"Wang X.","year":"2020","journal-title":"Advanced Materials"},{"key":"e_1_2_6_24_1","doi-asserted-by":"crossref","first-page":"806","DOI":"10.1002\/cctc.202001163","article-title":"The Synthesis and Catalytic Applications of Nanosized High\u2010Entropy Alloys","volume":"13","author":"Zheng H.","year":"2020","journal-title":"Chemcatchem"},{"key":"e_1_2_6_25_1","doi-asserted-by":"crossref","DOI":"10.1002\/sstr.202000033","article-title":"Nano High\u2010Entropy Materials: Synthesis Strategies and Catalytic Applications","volume":"1","author":"Li H.","year":"2020","journal-title":"Small Structures"},{"key":"e_1_2_6_26_1","doi-asserted-by":"crossref","DOI":"10.1002\/smtd.202500411","article-title":"Advanced Development of High\u2010Entropy Alloys in Catalytic Applications","volume":"10","author":"Zhu Z.","year":"2026","journal-title":"Small Methods"},{"key":"e_1_2_6_27_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202409949","article-title":"Spatial Structure of Electron Interactions in High\u2010entropy Oxide Nanoparticles for Active Electrocatalysis of Carbon Dioxide Reduction","volume":"36","author":"Cai W.","year":"2024","journal-title":"Advanced Materials"},{"key":"e_1_2_6_28_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.ijhydene.2025.152894","article-title":"Microwave Synthesis of High\u2010Entropy Alloy Catalysts on Different Carbon Supports for Oxygen Reduction Reactions and Carbon Dioxide Reduction Reactions","volume":"200","author":"Nath A. K.","year":"2026","journal-title":"International Journal of Hydrogen Energy"},{"key":"e_1_2_6_29_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.cej.2026.174327","article-title":"Mesoporous Single\u2010Phase High\u2010Entropy Oxides With Abundant Dual Cation\u2010Anion Vacancies and High Surface Area for Enhanced CO2 Hydrogenation and CO Oxidation","volume":"532","author":"Qing J.","year":"2026","journal-title":"Chemical Engineering Journal"},{"key":"e_1_2_6_30_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202504180","article-title":"High Entropy Alloy Formation Derived From High Entropy Oxide: Unlocking the Active Sites for Green Methanol Production From CO2","volume":"37","author":"Goud D.","year":"2025","journal-title":"Advanced Materials"},{"key":"e_1_2_6_31_1","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1039\/D2EE03185J","article-title":"A High\u2010Entropy Atomic Environment Converts Inactive to Active Sites for Electrocatalysis","volume":"16","author":"Zhu H.","year":"2023","journal-title":"Energy & Environmental Science"},{"key":"e_1_2_6_32_1","doi-asserted-by":"crossref","first-page":"10808","DOI":"10.1021\/acscatal.2c02604","article-title":"High\u2010Entropy Alloy With Mo\u2010Coordination as Efficient Electrocatalyst for Oxygen Evolution Reaction","volume":"12","author":"Mei Y.","year":"2022","journal-title":"ACS Catalysis"},{"key":"e_1_2_6_33_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.coelec.2023.101293","article-title":"High Entropy Alloy: From Theoretical Evaluation to Electrocatalytic Activity of Hydrogen Evolution Reaction","volume":"39","author":"Im S.","year":"2023","journal-title":"Current Opinion in Electrochemistry"},{"key":"e_1_2_6_34_1","doi-asserted-by":"crossref","DOI":"10.1002\/admt.202200882","article-title":"Electrosynthesis of Low Pt\u2010Loaded High Entropy Catalysts for Effective Hydrogen Evolution With Improved Acidic Durability","volume":"8","author":"Kim D.","year":"2022","journal-title":"Advanced Materials Technologies"},{"key":"e_1_2_6_35_1","doi-asserted-by":"crossref","DOI":"10.1002\/adfm.202418644","article-title":"Design and Synthesis of PtPdNiCoMn High\u2010Entropy Alloy Electrocatalyst for Enhanced Alkaline Hydrogen Evolution Reaction: A Theoretically Supported Predictive Design Approach","volume":"35","author":"Chandran M A.","year":"2024","journal-title":"Advanced Functional Materials"},{"key":"e_1_2_6_36_1","doi-asserted-by":"crossref","first-page":"1037","DOI":"10.1038\/s41467-025-56189-y","article-title":"Atomically Thin High\u2010Entropy Oxides via Naked Metal Ion Self\u2010Assembly for Proton Exchange Membrane Electrolysis","volume":"16","author":"Zhang T.","year":"2025","journal-title":"Nature Communications"},{"key":"e_1_2_6_37_1","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1038\/s41467-024-55627-7","article-title":"High\u2010Entropy Alloys Catalyzing Polymeric Transformation of Water Pollutants With Remarkably Improved Electron Utilization Efficiency","volume":"16","author":"Yao Z.","year":"2025","journal-title":"Nature Communications"},{"key":"e_1_2_6_38_1","doi-asserted-by":"crossref","first-page":"5928","DOI":"10.1021\/acscatal.5c00854","article-title":"Metal\u2010 and Site\u2010Specific Roles of High\u2010Entropy Spinel Oxides in Catalytic Oxidative Polymerization of Water Contaminants","volume":"15","author":"Mo Y.","year":"2025","journal-title":"ACS Catalysis"},{"key":"e_1_2_6_39_1","doi-asserted-by":"crossref","first-page":"2290","DOI":"10.1038\/s41467-024-45874-z","article-title":"Single\u2010Atom Mo\u2010Tailored High\u2010Entropy\u2010Alloy Ultrathin Nanosheets With Intrinsic Tensile Strain Enhance Electrocatalysis","volume":"15","author":"He L.","year":"2024","journal-title":"Nature Communications"},{"key":"e_1_2_6_40_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202206276","article-title":"High\u2010Entropy Intermetallic PtRhBiSnSb Nanoplates for Highly Efficient Alcohol Oxidation Electrocatalysis","volume":"34","author":"Chen W.","year":"2022","journal-title":"Advanced Materials"},{"key":"e_1_2_6_41_1","doi-asserted-by":"crossref","first-page":"4011","DOI":"10.1038\/s41467-019-11848-9","article-title":"Highly Efficient Decomposition of Ammonia Using High\u2010Entropy Alloy Catalysts","volume":"10","author":"Xie P.","year":"2019","journal-title":"Nature Communications"},{"key":"e_1_2_6_42_1","doi-asserted-by":"crossref","first-page":"6637","DOI":"10.1021\/acs.nanolett.3c01831","article-title":"Understanding the Structural Evolution of IrFeCoNiCu High\u2010Entropy Alloy Nanoparticles Under the Acidic Oxygen Evolution Reaction","volume":"23","author":"Maulana A. L.","year":"2023","journal-title":"Nano Letters"},{"key":"e_1_2_6_43_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.apcatb.2022.121472","article-title":"Efficient FeCoNiCuPd Thin\u2010Film Electrocatalyst for Alkaline Oxygen And Hydrogen Evolution Reactions","volume":"313","author":"Wang S.","year":"2022","journal-title":"Applied Catalysis B: Environmental"},{"key":"e_1_2_6_44_1","doi-asserted-by":"crossref","DOI":"10.1002\/aenm.202002593","article-title":"Octahedral Coordinated Trivalent Cobalt Enriched Multimetal Oxygen\u2010Evolution Catalysts","volume":"10","author":"Chen J.","year":"2020","journal-title":"Advanced Energy Materials"},{"key":"e_1_2_6_45_1","doi-asserted-by":"crossref","DOI":"10.1002\/adma.202310918","article-title":"In Situ Reconstruction of High\u2010Entropy Heterostructure Catalysts for Stable Oxygen Evolution Electrocatalysis Under Industrial Conditions","volume":"36","author":"Hu J.","year":"2024","journal-title":"Advanced Materials"}],"container-title":["Small"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/smll.76239","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/smll.76239","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/smll.76239","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T08:45:44Z","timestamp":1791794744000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/smll.76239"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,12]]},"references-count":44,"alternative-id":["10.1002\/smll.76239"],"URL":"https:\/\/doi.org\/10.1002\/smll.76239","archive":["Portico"],"relation":{},"ISSN":["1613-6810","1613-6829"],"issn-type":[{"value":"1613-6810","type":"print"},{"value":"1613-6829","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,12]]},"assertion":[{"value":"2026-05-18","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-10-06","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-10-12","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e76239"}}