Mechanistic Insights into Binding, Configuration, Coverage, and Reaction Rates of Hydrogen on Platinum Surfaces

Mechanistic Insights into Binding, Configuration, Coverage, and Reaction Rates of Hydrogen on Platinum Surfaces | 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 Mechanistic Insights into Binding, Configuration, Coverage, and Reaction Rates of Hydrogen on Platinum Surfaces Yi Rao, Hui Wang, Haley Fisher, Haibin Wu, Jesse Brown, Zhi-Chao Huang-Fu, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8819085/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 Hydrogen is a clean alternative to fossil fuels to generate power for heat, industry, electricity, and transportation. Pt is a benchmark electrocatalyst for hydrogen evolution and oxidation reactions (HER/HOR) due to its intrinsic activity. Consequently, Pt-based catalysts have become primary platforms for fundamental studies of HER/HOR mechanisms. Herein, we utilize surface-specific electrochemical sum frequency generation spectroscopy (EC-SFG) to observe HER/HOR intermediates on Pt in situ. We assign two distinct adsorbed hydrogen (*H) resonances as step- and terrace-bound species before quantifying their unique Stark effects and interfacial orientation. We analyze the kinetics of HER; quantifying rate constants for *H generation and H 2 production through the Heyrovsky or Tafel steps for overpotential- and underpotential-deposited (OPD and UPD) species. We quantify *H surface coverage density as a function of potential to calculate potential-dependent binding energies. Through these analyses, we compose a succinct view of the HER mechanism on Pt electrodes: Under OPD conditions, the Volmer-Tafel mechanism is promoted due to higher surface density and lower binding energy, while UPD conditions promote the Volmer-Heyrovsky mechanism. These findings are supported by our orientational analysis where a smaller Pt–H angle promotes the Tafel step under OPD conditions. The Heyrovsky step is rate-limiting at UPD while the Tafel step is rate-limiting for OPD conditions, with the Volmer step proceeding faster than either H 2 evolution mechanism. This site-specific understanding of HER/HOR on Pt electrodes will inform mechanisms for other electrode systems and promote EC-SFG as a critical tool in electrochemical mechanistic investigations. Physical sciences/Chemistry/Electrochemistry/Electrocatalysis Physical sciences/Chemistry/Surface chemistry/Surface spectroscopy Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SI01242026PtHHuiWangNatureCommunications.docx Mechanistic Insights into Binding, Configuration, Coverage, and Reaction Rates of Hydrogen on Platinum Surfaces 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-8819085","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":596001734,"identity":"5da0be73-2444-40c5-a5eb-53db82ad5b5e","order_by":0,"name":"Yi 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Pt is a benchmark electrocatalyst for hydrogen evolution and oxidation reactions (HER/HOR) due to its intrinsic activity. Consequently, Pt-based catalysts have become primary platforms for fundamental studies of HER/HOR mechanisms. Herein, we utilize surface-specific electrochemical sum frequency generation spectroscopy (EC-SFG) to observe HER/HOR intermediates on Pt in situ. We assign two distinct adsorbed hydrogen (*H) resonances as step- and terrace-bound species before quantifying their unique Stark effects and interfacial orientation. We analyze the kinetics of HER; quantifying rate constants for *H generation and H\u003csub\u003e2\u003c/sub\u003e production through the Heyrovsky or Tafel steps for overpotential- and underpotential-deposited (OPD and UPD) species. We quantify *H surface coverage density as a function of potential to calculate potential-dependent binding energies. 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