{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T06:35:55Z","timestamp":1773210955283,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T00:00:00Z","timestamp":1773100800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51874156"],"award-info":[{"award-number":["51874156"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Major Scientific and Technological Project of the Panxi National Demonstration Zone","award":["SC2022A1H01L"],"award-info":[{"award-number":["SC2022A1H01L"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Despite decades of research into high-temperature oxidation kinetics, the atomic-scale origin of oxygen radical formation\u2014a critical driver of the synthesis of functional oxide materials, oxidation corrosion of alloys, and combustion of fuels\u2014remains elusive. Here, we unveil a previously unrecognized \u201coxygen clustering\u2013radical release\u201d pathway at the molecular level, wherein transient van der Waals aggregates of oxygen molecules, rather than isolated O2, serve as the primary radical source. Through an integrated computational strategy combining first-principles calculations and deep neural network potential function molecular dynamics, we demonstrate that oxygen clusters exhibit a pronounced odd\u2013even oscillation in stability: even-numbered clusters (especially O6\/O8 subunits) are chemically inert, whereas odd-numbered clusters (dominated by O3) possess high reactivity. Kinetically, clusters evolve via reversible aggregation\u2013dissociation, and upon reaching a critical size, undergo structural collapse accompanied by radical release\u2014a process initiated predominantly by large odd-numbered clusters. This mechanism persists in both pure O2 and TiCl4-containing environments, with TiCl4 modulating only the aggregation kinetics, not the fundamental pathway. Our work establishes oxygen clustering as a universal, spontaneous source of radicals in high-temperature oxidation, providing a new molecular-level mechanistic framework for understanding and controlling radical-driven processes in materials synthesis, corrosion and combustion.<\/jats:p>","DOI":"10.3390\/ma19061048","type":"journal-article","created":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T08:43:31Z","timestamp":1773132211000},"page":"1048","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Evolution of High-Temperature Oxygen Clusters and Radical Release: A Molecular Dynamics Study in Pure Oxygen and Titanium Tetrachloride Oxidation Environments"],"prefix":"10.3390","volume":"19","author":[{"given":"Dongqin","family":"Li","sequence":"first","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"},{"name":"State Key Laboratory of Vanadium and Titanium Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jie","family":"Zhou","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ping","family":"Lu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Vanadium and Titanium Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Linfei","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhuo","family":"Sheng","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"},{"name":"State Key Laboratory of Vanadium and Titanium Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yunmin","family":"Chen","sequence":"additional","affiliation":[{"name":"Beijing DP Technology Co., Ltd., Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rong","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Caiqing","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1660-6106","authenticated-orcid":false,"given":"Xiumin","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"},{"name":"National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dachun","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, School of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China"},{"name":"National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1016\/j.proci.2010.05.011","article-title":"First-principles thermochemistry for the combustion of TiCl4 in a methane flame","volume":"33","author":"Totton","year":"2011","journal-title":"Proc. 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