Computational Investigation on the Mechanism of Electrocatalytic Water Oxidation by Copper(II) Porphyrin

Computational Investigation on the Mechanism of Electrocatalytic Water Oxidation by Copper(II) Porphyrin | 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 Computational Investigation on the Mechanism of Electrocatalytic Water Oxidation by Copper(II) Porphyrin Shanti Gopal Patra, Aritra Saha, Pratim Kumar Chattaraj This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5561166/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 In a recent report ( Chem. Sci. , 2019 , 10 , 2613–2622), it was shown that the copper(II) complex of tetrakis(4-N-methylpyridyl)porphyrin serves as an electrocatalyst towards an efficient oxygen evolution reaction (OER) with an onset overpotential of 310 mV. Motivated by the experimental work, we perform the density functional theory (DFT) calculation in a water medium employing the solvation molecular dynamics (SMD) model to find out the mechanism of the water oxidation process by taking unsubstituted porphyrin (L). Three mechanisms are constructed. Mechanism I starts from the water-coordinated complex [LCu II -OH 2 ] ( 1 ), which undergoes a proton-coupled electron transfer (PCET) reaction to [LCu III -OH 2 ] + ( 2 ) with a redox potential E = 0.81 V vs. SHE. Then, it undergoes deprotonation to form [LCu III -OH] ( 3 ), followed by one-electron oxidation at E = 1.33 V vs. SHE to form [LCu IV -OH] + ( 4 ). Then, 4 undergoes deprotonation from [LCu IV =O] ( 6 ). Next, water attacks the oxygen atom of 4 , followed by two further PCET processes with potential < 1 V vs. NHE from the oxygen-bound copper species with steps [LCu II =O- + OH 2 ] ( 7 ) → [LCu II -OH-OH] ( 8 ) → [LCu II -O • -OH] ( 7 ) → [LCu II -O = O] ( 9 ). The activation barrier for the step [LCu II =O- + OH 2 ] ( 7 ) → [LCu II -OH-OH] ( 8 ) is calculated to be 5.6 kcal/mol. In mechanism II, [LCu III -OH] ( 3 ) → [LCu IV =O] ( 5 ) considered with E = 2.08 V vs. NHE. In mechanism III, the attack of water to 5 with the PCET process to form [LCu II - – O-OH] – ( 10 ) followed by oxidation to [LCu II - • O-O – ] – ( 11 ) and [LCu II -O = O] ( 9 ). For the PCET oxidation of 1 to [LCu III -OH] ( 3 ), the redox potential is 1.70 V vs. SHE. It is concluded that mechanism I is more likely to take place with an onset potential E = 1.33 V vs. SHE, giving rise to an overpotential of 100 mV. Further modification of the redox potential can be made by employing substituted porphyrin systems. Copper(II) porphyrin electrocatalytic water oxidation reaction (OER) DFT free energy profile redox potential QTAIM Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformationrebuttal.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-5561166","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":444093318,"identity":"881ff63d-5699-47ea-b394-11850bd8ea75","order_by":0,"name":"Shanti Gopal Patra","email":"","orcid":"","institution":"National Institute of Technology Silchar","correspondingAuthor":false,"prefix":"","firstName":"Shanti","middleName":"Gopal","lastName":"Patra","suffix":""},{"id":444093320,"identity":"df0e9098-f8c2-43ab-8df0-4d4f3fff6ab5","order_by":1,"name":"Aritra Saha","email":"","orcid":"","institution":"National Institute of Technology Silchar","correspondingAuthor":false,"prefix":"","firstName":"Aritra","middleName":"","lastName":"Saha","suffix":""},{"id":444093321,"identity":"bbf9ecb9-6462-4199-9bf8-612bd3d8516a","order_by":2,"name":"Pratim Kumar Chattaraj","email":"data:image/png;base64,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","orcid":"","institution":"Birla Institute of Technology","correspondingAuthor":true,"prefix":"","firstName":"Pratim","middleName":"Kumar","lastName":"Chattaraj","suffix":""}],"badges":[],"createdAt":"2024-12-02 04:08:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5561166/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5561166/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86302007,"identity":"83672f3c-f96a-4af7-9535-ac77b89fb028","added_by":"auto","created_at":"2025-07-09 06:33:02","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":968584,"visible":true,"origin":"","legend":"","description":"","filename":"Cuporrevisedv2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5561166/v1_covered_b4355487-a120-4366-8333-5dddfbc12c60.pdf"},{"id":80884314,"identity":"9526d91b-6064-46fa-add7-dab9e6781c61","added_by":"auto","created_at":"2025-04-18 08:23:58","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":856190,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryInformationrebuttal.docx","url":"https://assets-eu.researchsquare.com/files/rs-5561166/v1/b38cc7caa260c6704111887c.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Computational Investigation on the Mechanism of Electrocatalytic Water Oxidation by Copper(II) Porphyrin","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"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},"keywords":"Copper(II) porphyrin, electrocatalytic water oxidation reaction (OER), DFT, free energy profile, redox potential, QTAIM","lastPublishedDoi":"10.21203/rs.3.rs-5561166/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5561166/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn a recent report (\u003cem\u003eChem. Sci.\u003c/em\u003e, \u003cb\u003e2019\u003c/b\u003e, \u003cem\u003e10\u003c/em\u003e, 2613\u0026ndash;2622), it was shown that the copper(II) complex of tetrakis(4-N-methylpyridyl)porphyrin serves as an electrocatalyst towards an efficient oxygen evolution reaction (OER) with an onset overpotential of 310 mV. Motivated by the experimental work, we perform the density functional theory (DFT) calculation in a water medium employing the solvation molecular dynamics (SMD) model to find out the mechanism of the water oxidation process by taking unsubstituted porphyrin (L). Three mechanisms are constructed. Mechanism I starts from the water-coordinated complex [LCu\u003csup\u003eII\u003c/sup\u003e-OH\u003csub\u003e2\u003c/sub\u003e] (\u003cb\u003e1\u003c/b\u003e), which undergoes a proton-coupled electron transfer (PCET) reaction to [LCu\u003csup\u003eIII\u003c/sup\u003e-OH\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003e (\u003cb\u003e2\u003c/b\u003e) with a redox potential \u003cem\u003eE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.81 V vs. SHE. Then, it undergoes deprotonation to form [LCu\u003csup\u003eIII\u003c/sup\u003e-OH] (\u003cb\u003e3\u003c/b\u003e), followed by one-electron oxidation at \u003cem\u003eE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.33 V vs. SHE to form [LCu\u003csup\u003eIV\u003c/sup\u003e-OH]\u003csup\u003e+\u003c/sup\u003e (\u003cb\u003e4\u003c/b\u003e). Then, \u003cb\u003e4\u003c/b\u003e undergoes deprotonation from [LCu\u003csup\u003eIV\u003c/sup\u003e=O] (\u003cb\u003e6\u003c/b\u003e). Next, water attacks the oxygen atom of \u003cb\u003e4\u003c/b\u003e, followed by two further PCET processes with potential\u0026thinsp;\u0026lt;\u0026thinsp;1 V vs. NHE from the oxygen-bound copper species with steps [LCu\u003csup\u003eII\u003c/sup\u003e=O-\u003csup\u003e+\u003c/sup\u003eOH\u003csub\u003e2\u003c/sub\u003e] (\u003cb\u003e7\u003c/b\u003e) \u0026rarr; [LCu\u003csup\u003eII\u003c/sup\u003e-OH-OH] (\u003cb\u003e8\u003c/b\u003e) \u0026rarr; [LCu\u003csup\u003eII\u003c/sup\u003e-O\u003csup\u003e\u0026bull;\u003c/sup\u003e-OH] (\u003cb\u003e7\u003c/b\u003e) \u0026rarr; [LCu\u003csup\u003eII\u003c/sup\u003e-O\u0026thinsp;=\u0026thinsp;O] (\u003cb\u003e9\u003c/b\u003e). The activation barrier for the step [LCu\u003csup\u003eII\u003c/sup\u003e=O-\u003csup\u003e+\u003c/sup\u003eOH\u003csub\u003e2\u003c/sub\u003e] (\u003cb\u003e7\u003c/b\u003e) \u0026rarr; [LCu\u003csup\u003eII\u003c/sup\u003e-OH-OH] (\u003cb\u003e8\u003c/b\u003e) is calculated to be 5.6 kcal/mol. In mechanism II, [LCu\u003csup\u003eIII\u003c/sup\u003e-OH] (\u003cb\u003e3\u003c/b\u003e) \u0026rarr; [LCu\u003csup\u003eIV\u003c/sup\u003e=O] (\u003cb\u003e5\u003c/b\u003e) considered with \u003cem\u003eE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.08 V vs. NHE. In mechanism III, the attack of water to 5 with the PCET process to form [LCu\u003csup\u003eII\u003c/sup\u003e-\u003csup\u003e\u0026ndash;\u003c/sup\u003eO-OH]\u003csup\u003e\u0026ndash;\u003c/sup\u003e (\u003cb\u003e10\u003c/b\u003e) followed by oxidation to [LCu\u003csup\u003eII\u003c/sup\u003e-\u003csup\u003e\u0026bull;\u003c/sup\u003eO-O\u003csup\u003e\u0026ndash;\u003c/sup\u003e]\u003csup\u003e\u0026ndash;\u003c/sup\u003e (\u003cb\u003e11\u003c/b\u003e) and [LCu\u003csup\u003eII\u003c/sup\u003e-O\u0026thinsp;=\u0026thinsp;O] (\u003cb\u003e9\u003c/b\u003e). For the PCET oxidation of \u003cb\u003e1\u003c/b\u003e to [LCu\u003csup\u003eIII\u003c/sup\u003e-OH] (\u003cb\u003e3\u003c/b\u003e), the redox potential is 1.70 V vs. SHE. It is concluded that mechanism I is more likely to take place with an onset potential \u003cem\u003eE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.33 V vs. SHE, giving rise to an overpotential of 100 mV. Further modification of the redox potential can be made by employing substituted porphyrin systems.\u003c/p\u003e","manuscriptTitle":"Computational Investigation on the Mechanism of Electrocatalytic Water Oxidation by Copper(II) Porphyrin","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-18 08:23:41","doi":"10.21203/rs.3.rs-5561166/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":"74b27e56-a137-41a4-b31e-a79332b9f08d","owner":[],"postedDate":"April 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-09T06:24:25+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-18 08:23:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5561166","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5561166","identity":"rs-5561166","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}