Distinct solvation patterns of OH– versus H3O+ charge defects at electrified gold/water interfaces govern their properties

Distinct solvation patterns of OH– versus H3O+ charge defects at electrified gold/water interfaces govern their properties | 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 Article Distinct solvation patterns of OH – versus H 3 O + charge defects at electrified gold/water interfaces govern their properties Chanbum Park, Soumya Ghosh, Harald Forbert, Dominik Marx This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5495637/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 19 Sep, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Understanding the solvation structures and charge migration mechanisms of OH – and H 3 O + species at metal interfaces as a function of bias potential is imperative for developing more efficient electrochemical devices. In this paper, we report the detailed solvation structures of OH – and H 3 O + at gold electrodes relevant to alkaline and acidic aqueous conditions using ab initio molecular dynamics simulations at finite bias potentials. Our findings reveal that the adsorption propensities of OH – and H 3 O + are strongly influenced by the oscillating net atomic charge of water normal to the electrified interface. This leads to preferentially adsorbed OH – in the first water layer extremely close to the gold surface even at zero bias, while H 3 O + is expelled toward the second layer even under negative bias potentials. Due to the combined effects of the net atomic charge of water in the different solvation layers and local polarization effects of the gold surface, OH – exhibits peculiar hypercoordinated solvation structures in its resting and active state for charge migration very different from those known from OH – in bulk water. We find that gold atoms strongly interact with both OH – solvation complexes and effectively replace hydrogen-bond-donating water molecules, while H 3 O + is not much affected compared to bulk. The active state of OH – is particularly distorted due to being anchored at two neighboring gold atoms that are far apart such that the free energy barrier for charge transfer gets strongly increased, thus lowering the corresponding rate. Physical sciences/Chemistry/Theoretical chemistry/Molecular dynamics Physical sciences/Chemistry/Electrochemistry/Electrocatalysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SI.pdf Supplementary Information Cite Share Download PDF Status: Published Journal Publication published 19 Sep, 2025 Read the published version in Nature Communications → 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-5495637","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":385232244,"identity":"857e7bcf-acbf-43fa-a8cf-6c85e7c6bca5","order_by":0,"name":"Chanbum Park","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0002-8613-9278","institution":"Ruhr-Universitaet Bochum","correspondingAuthor":true,"prefix":"","firstName":"Chanbum","middleName":"","lastName":"Park","suffix":""},{"id":385232245,"identity":"ac86a7cd-d736-497f-a29b-71d1011c10c0","order_by":1,"name":"Soumya Ghosh","email":"","orcid":"","institution":"Tata Institute of Fundamental Research Hyderabad","correspondingAuthor":false,"prefix":"","firstName":"Soumya","middleName":"","lastName":"Ghosh","suffix":""},{"id":385232246,"identity":"4991a330-70ef-4906-b31a-2cf39df7413c","order_by":2,"name":"Harald Forbert","email":"","orcid":"","institution":"Ruhr-Universität Bochum","correspondingAuthor":false,"prefix":"","firstName":"Harald","middleName":"","lastName":"Forbert","suffix":""},{"id":385232247,"identity":"397e75d7-3b80-4766-b115-66c56203006f","order_by":3,"name":"Dominik Marx","email":"","orcid":"","institution":"Ruhr-Universitaet Bochum","correspondingAuthor":false,"prefix":"","firstName":"Dominik","middleName":"","lastName":"Marx","suffix":""}],"badges":[],"createdAt":"2024-11-21 07:30:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5495637/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5495637/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-63832-1","type":"published","date":"2025-09-19T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":70794551,"identity":"15c8944b-02f8-4270-858a-522ed19e9132","added_by":"auto","created_at":"2024-12-06 20:27:14","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1304510,"visible":true,"origin":"","legend":"\u003cp\u003eSimulation cell setups, charge migration tracking of the H3O+ and OH– charge defects and density profiles for acidic and alkaline aqueous electrolytes at Au interfaces at finite bias and pzc conditions. Configuration snapshots of the electrochemical simulation cells hosting dissociated a HClO4 and b NaOH in water between the gold electrode (left) and an inert neon-based computational counter electrode (right) required to apply finite bias.28 c Representative migration pathways of the H3O+ and OH– charge defects (see text for the tagging approach) from the bulk-like regime (visualized by the snapshots in panel a and b) to the electrified interfacial region as a result of applying constant potential bias of −3 and +1 V, respectively; the horizontal dashed line delimits the interfacial water layer according to the density profiles in panels d and e. Density profiles of all O, H, and Au atoms as well as of the O sites of H3O+ and OH– for the d acidic and e alkaline solutions visualized in panels a and b at −3 and +1 V, respectively; the potential of zero charge (pzc) results are shown for reference, and arrows highlight features discussed in the text. The interfacial (IF) and bulk-like (BL) regions are defined as z ≤ 12 °A and z \u0026gt; 16 °A relative to the bottom-most fixed Au layer indicated by vertical dashed and dotted lines, respectively, while the intermediate (IM) region is in between.\u003c/p\u003e","description":"","filename":"Parkfig1.png","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/ff9dde1262b265df4970a31c.png"},{"id":70794766,"identity":"e1d9b16f-414e-4929-bb12-fb748144b765","added_by":"auto","created_at":"2024-12-06 20:35:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":825447,"visible":true,"origin":"","legend":"\u003cp\u003eOrientations of H3O+ (split in Eigen and Zundel states, see text) and OH– defects in the interfacial\u003c/p\u003e\n\u003cp\u003eregion at finite bias and pzc conditions. Probability distribution functions of the cosine of the angle q of a the OH vectors in H3O+, b the angle formed by two oxygen atoms in a Zundel state, and c the OH vector of OH– all with respect to the surface normal without (pzc) and subject to the indicated bias. Representative snapshots visualizing the most probably arrangements are shown in the lower panels.\u003c/p\u003e","description":"","filename":"Parkfig2.png","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/c9ab0d419c8aa037f87afb28.png"},{"id":70794555,"identity":"1f38b00c-ace7-4ba6-a02a-cab885df3cda","added_by":"auto","created_at":"2024-12-06 20:27:14","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1085643,"visible":true,"origin":"","legend":"\u003cp\u003eFigure 3: Radial distribution functions, charge transfer free energies of H3O+ and OH– and structural anal-ysis at finite bias and pzc conditions. RDFs of a Oa (H3O+) and b O∗ (OH–) with respect to the oxygen (O) atoms of the water molecules in the interface (IF) and bulk-like (BL) regions, respectively; here Oa and O∗ indicate\u003c/p\u003e\n\u003cp\u003ethe oxygen atom in the H3O+ and OH– ions, respectively. c Distribution function of the distance between O∗ and the closest Au atom to O∗ and ˜O, respectively, as defined in the text. The average O∗–O˜ (IF), O∗–O˜ (BL), Au∗–Au˜ and Au–Au (1st layer) distances are 2.66, 2.63, 3.14 and 3.02 °A. Free energy profiles along the charge transfer coordinate δ for d H3O+ and e OH– (see the definition of δ in the main text). The horizontal dotted lines indicate the thermal energy kBT . Representative snapshots of proton hole transfer events resulting in charge migration of OH– within the f BL and g IF regions.\u003c/p\u003e","description":"","filename":"Parkfig3.png","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/efde7a0c88d2e4d66fd2d1f7.png"},{"id":70794552,"identity":"bfb95740-9ea2-40ce-ab1a-f33f91f53c66","added_by":"auto","created_at":"2024-12-06 20:27:14","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1016120,"visible":true,"origin":"","legend":"\u003cp\u003eNet atomic charge analyses and hydrogen bond statistics of the OH– and H3O+ charge defects in the NaOH and HClO4 aqueous solutions close to the gold/water interface at respective potential biases of +1 and −3 V. a Excess charge profile ∆q(z) computed from the net atomic charge (NAC) of the oxygen and hydrogen atoms of the H2O molecules along the surface normal in the alkaline (circles) and acidic (crosses) elec-trolytes systems and for reference in neat water at zero bias (upward triangles). Downward triangles and squares represent the total net charge of the OH– and H3O+ ions, respectively. The density profiles ρ(z) of OH– and H3O+ (right y-scale) are shown in red and blue lines, respectively. b Average NAC of Au∗ and of the second-nearest neighbors (2nd n.n.) of Au∗ as well as average total net charge of OH– obtained from the NACs of its H and O atom depending on the hydrogen bonding state of OH– being in the IF region; DnAm denotes that OH– donates n and accepts m HBs while ⊥ and || define the two distinct orientations of the D1A3 state according to panels g and h, respectively. c Average number N of donor (D) and acceptor (A) HBs of OH– in its “resting” and “active” state (blue bars); see text. Orange bars on the top of the blue bars indicate the number of nearby Au atoms (see text). d Distribution function of the NAC of O∗, ˜O and O (in the BL region) in the resting state of OH–. e Distribu-tion function of the NAC of Au∗, Au˜ and Au in the first layer while OH– is in the resting state. f-i Representative DnAm solvation states of OH– near the Au surface analyzed in panel b; Au∗ is highlighted in bright orange while the water molecules which are not associated with the solvation shell of OH– (cyan) are not presented.\u003c/p\u003e","description":"","filename":"Parkfig4.png","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/228dc87b1f0e62f1ec526fd3.png"},{"id":70794553,"identity":"2d6369c0-3f69-42f9-b8bd-f3a7ca3e2cf8","added_by":"auto","created_at":"2024-12-06 20:27:14","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":395202,"visible":true,"origin":"","legend":"\u003cp\u003eCharge transfer mechanism at the alkaline gold/water interface via the OH– charge defect. The representative snapshots in panels a-c illustrate the sol-vation structure of the OH– charge defect in the a bulk like (BL), b intermediate (IM) and c interfacial (IF) re-gions. In panel a, the water molecules which are not as-sociated with the hypercoordinated first solvation shell (see text) of OH– (cyan) are not presented while panels b and c include water molecules (gray) beyond the first solvation shell (oxygen in red). Representative time se-ries referenced to the charge transfer event at t = 0 fs of d the charge transfer coordinate |δ | involving the re-spective O∗, e the NAC of the involved AuI and AuII atoms, and f the respective OI–AuI and OII–AuII dis-tances d; see panels g–i for corresponding atom label-ing. g-i Schematic illustration of the interfacial charge transfer mechanism of OH– from the initial resting state via the active state to the final resting state anchored on the Au surface, see text, where the arrows indicate the corresponding times in panel f.\u003c/p\u003e","description":"","filename":"Parkfig5.png","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/caaaf3d2b024be978b817cbc.png"},{"id":91756988,"identity":"d5f0fbb8-6d62-4415-b339-98a73877e16a","added_by":"auto","created_at":"2025-09-20 07:05:40","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3605239,"visible":true,"origin":"","legend":"","description":"","filename":"MSp8imaged.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1_covered_b954ed71-4954-49d3-874f-96ef930728cb.pdf"},{"id":70552090,"identity":"36b2b8ec-c037-453d-a431-2f377225740a","added_by":"auto","created_at":"2024-12-04 10:22:30","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1404157,"visible":true,"origin":"","legend":"Supplementary Information","description":"","filename":"SI.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5495637/v1/6ab74eb10c3e6a27ec67c480.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Distinct solvation patterns of OH\u003csup\u003e–\u003c/sup\u003e versus H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e charge defects at\r\nelectrified gold/water interfaces govern their properties","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5495637/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5495637/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Understanding the solvation structures and charge migration mechanisms of OH\u003csup\u003e–\u003c/sup\u003e and H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e species at metal interfaces as a function of bias potential is imperative for developing more efficient electrochemical devices. In this paper, we report the detailed solvation structures of OH\u003csup\u003e–\u003c/sup\u003e and H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e at gold electrodes relevant to alkaline and acidic aqueous conditions using ab initio molecular dynamics simulations at finite bias potentials. Our findings reveal that the adsorption propensities of OH\u003csup\u003e–\u003c/sup\u003e and H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e are strongly influenced by the oscillating net atomic charge of water normal to the electrified interface. This leads to preferentially adsorbed OH\u003csup\u003e–\u003c/sup\u003e in the first water layer extremely close to the gold surface even at zero bias, while H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e is expelled toward the second layer even under negative bias potentials. Due to the combined effects of the net atomic charge of water in the different solvation layers and local polarization effects of the gold surface, OH\u003csup\u003e–\u003c/sup\u003e exhibits peculiar hypercoordinated solvation structures in its resting and active state for charge migration very different from those known from OH\u003csup\u003e–\u003c/sup\u003e in bulk water. We find that gold atoms strongly interact with both OH\u003csup\u003e–\u003c/sup\u003e solvation complexes and effectively replace hydrogen-bond-donating water molecules, while H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e is not much affected compared to bulk. The active state of OH\u003csup\u003e–\u003c/sup\u003e is particularly distorted due to being anchored at two neighboring gold atoms that are far apart such that the free energy barrier for charge transfer gets strongly increased, thus lowering the corresponding rate.","manuscriptTitle":"Distinct solvation patterns of OH– versus H3O+ charge defects at\nelectrified gold/water interfaces govern their properties","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-04 10:22:26","doi":"10.21203/rs.3.rs-5495637/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"79ca9340-1b95-4d72-8710-0ec06cfb84ba","owner":[],"postedDate":"December 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":41036928,"name":"Physical sciences/Chemistry/Theoretical chemistry/Molecular dynamics"},{"id":41036929,"name":"Physical sciences/Chemistry/Electrochemistry/Electrocatalysis"}],"tags":[],"updatedAt":"2025-09-20T07:05:26+00:00","versionOfRecord":{"articleIdentity":"rs-5495637","link":"https://doi.org/10.1038/s41467-025-63832-1","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2025-09-19 04:00:00","publishedOnDateReadable":"September 19th, 2025"},"versionCreatedAt":"2024-12-04 10:22:26","video":"","vorDoi":"10.1038/s41467-025-63832-1","vorDoiUrl":"https://doi.org/10.1038/s41467-025-63832-1","workflowStages":[]},"version":"v1","identity":"rs-5495637","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5495637","identity":"rs-5495637","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}