Synergistic Modulation of Superoxide Radicals and Singlet Oxygen via Band-Engineered CDs-TiO₂ Heterojunctions for Efficient Solar-to-H₂O₂ Conversion

Synergistic Modulation of Superoxide Radicals and Singlet Oxygen via Band-Engineered CDs-TiO₂ Heterojunctions for Efficient Solar-to-H₂O₂ Conversion | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synergistic Modulation of Superoxide Radicals and Singlet Oxygen via Band-Engineered CDs-TiO₂ Heterojunctions for Efficient Solar-to-H₂O₂ Conversion Song Zhang, Jiaojiao Li, Zhan Jiang, Yuanyuan Zhang, Xiaoli Yang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9194788/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Photocatalytic technology holds immense promise for energy conversion and environmental purification, yet current photocatalysts are often hampered by wide bandgaps, rapid charge carrier recombination, and poor selectivity for reactive oxygen species (ROS). Moreover, the roles of different ROS in photocatalytic reactions remain unclear. To address these challenges, we constructed tunable Z-scheme heterojunctions by coupling anatase TiO₂ nanoparticles (< 5 nm) with four types of absorption-tailored carbon dots (Blue, Green, Orange, and Red). Precise band structure modulation enabled control over charge transfer pathways and ROS generation, thereby achieving enhanced photocatalytic performance at the level of the material's microstructure. By effectively manipulating the charge carrier transfer pathways, these newly formed heterojunctions successfully generate a significant divergence in the concentrations of key reactive oxygen species: the superoxide radicals (·O₂⁻), hydroxyl radicals (·OH), and singlet oxygen (¹O₂). This distinction in ROS generation capabilities is directly manifested in the photocatalytic performance. Specifically, for hydrogen peroxide (H₂O₂) production, the OCDs-TiO₂ composite achieved an impressive H₂O₂ production rate of 292 µmol·g⁻¹·h⁻¹ (12× higher than pure TiO₂) and 90% methyl orange degradation within 30 min(Figure S1 .). Mechanistic studies confirm that the synergy of ·O₂⁻ and ¹O₂ is critical for enhanced performance. OCDs-TiO₂ heterojunction maximizes the synergistic generation of superoxide radicals (·O₂⁻) and singlet oxygen (¹O₂). For the first time, we demonstrate the customized fabrication of TiO₂ NPs heterojunctions through precisely regulating their band structure using four types of CDs. It reveals the crucial principle that the bandgap width of CDs determines the charge transfer pathway and resultant ROS concentration, thereby providing a band engineering strategy for optimizing TiO₂ NPs based photocatalysts. Titanium Dioxide Carbon Dots Photocatalytic H₂O₂ Production Band Engineering Reactive Oxygen Species (ROS) Full Text Additional Declarations No competing interests reported. Tables are available in the Supplementary Files section. Supplementary Files Tables.docx Supportinginformation.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9194788","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":615525973,"identity":"fc12d92c-1106-4bcb-aeff-62eeaa0aa036","order_by":0,"name":"Song Zhang","email":"","orcid":"","institution":"Qingdao University","correspondingAuthor":false,"prefix":"","firstName":"Song","middleName":"","lastName":"Zhang","suffix":""},{"id":615525974,"identity":"b543b663-80a3-48ca-91d1-26d061ff4091","order_by":1,"name":"Jiaojiao Li","email":"","orcid":"","institution":"Qingdao 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(ROS)","lastPublishedDoi":"10.21203/rs.3.rs-9194788/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9194788/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePhotocatalytic technology holds immense promise for energy conversion and environmental purification, yet current photocatalysts are often hampered by wide bandgaps, rapid charge carrier recombination, and poor selectivity for reactive oxygen species (ROS). Moreover, the roles of different ROS in photocatalytic reactions remain unclear. To address these challenges, we constructed tunable Z-scheme heterojunctions by coupling anatase TiO₂ nanoparticles (\u0026lt;\u0026thinsp;5 nm) with four types of absorption-tailored carbon dots (Blue, Green, Orange, and Red). Precise band structure modulation enabled control over charge transfer pathways and ROS generation, thereby achieving enhanced photocatalytic performance at the level of the material's microstructure. By effectively manipulating the charge carrier transfer pathways, these newly formed heterojunctions successfully generate a significant divergence in the concentrations of key reactive oxygen species: the superoxide radicals (\u0026middot;O₂⁻), hydroxyl radicals (\u0026middot;OH), and singlet oxygen (\u0026sup1;O₂). This distinction in ROS generation capabilities is directly manifested in the photocatalytic performance. Specifically, for hydrogen peroxide (H₂O₂) production, the OCDs-TiO₂ composite achieved an impressive H₂O₂ production rate of 292 \u0026micro;mol\u0026middot;g⁻\u0026sup1;\u0026middot;h⁻\u0026sup1; (12\u0026times; higher than pure TiO₂) and 90% methyl orange degradation within 30 min(Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e.). Mechanistic studies confirm that the synergy of \u0026middot;O₂⁻ and \u0026sup1;O₂ is critical for enhanced performance. OCDs-TiO₂ heterojunction maximizes the synergistic generation of superoxide radicals (\u0026middot;O₂⁻) and singlet oxygen (\u0026sup1;O₂). For the first time, we demonstrate the customized fabrication of TiO₂ NPs heterojunctions through precisely regulating their band structure using four types of CDs. It reveals the crucial principle that the bandgap width of CDs determines the charge transfer pathway and resultant ROS concentration, thereby providing a band engineering strategy for optimizing TiO₂ NPs based photocatalysts.\u003c/p\u003e","manuscriptTitle":"Synergistic Modulation of Superoxide Radicals and Singlet Oxygen via Band-Engineered CDs-TiO₂ Heterojunctions for Efficient Solar-to-H₂O₂ Conversion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-01 18:24:54","doi":"10.21203/rs.3.rs-9194788/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"77496ffb-63f5-4036-81f6-27d52fbd2648","owner":[],"postedDate":"April 1st, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-23T07:27:03+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-01 18:24:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9194788","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9194788","identity":"rs-9194788","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}