Breaking the scaling relation for the Tafel hydrogen evolution step by proximity induced magnetism

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• Gilberto Teobaldi, STFC UKRI
• Monday 10 March 2025, 14:30-15:00
• zoom.us/j/92447982065?pwd=RkhaYkM5VTZPZ3pYSHptUXlRSkppQT09.

If you have a question about this talk, please contact Dr Sun-Woo Kim.

To electrify society, new electrocatalysts with higher turnover frequencies and decreased overpotentials are needed. New materials are sought that change the energy of intermediates and transition states on the reaction pathway to deliver a change in rate. But a fundamental challenge is that scaling relationships exist for many electrocatalytic mechanisms. These relationships limit the maximum achievable activity and the efficiency of electrocatalytic energy generation.

Here, we present a Density Functional Theory (DFT) study of the role of spin-polarisation at Au and Pt surfaces for the kinetics of the Tafel Hydrogen Evolution Step (THES). The DFT simulations uncover an electrode-dependent response to spin-polarisation at the surface with the ensuing possibility of both increasing (Pt) or decreasing (Au) the rate-determining barrier for the THES . The DFT simulations identify the leading terms of the calculated THES enhancement (Pt) and suppression (Au) in the different electronic and phonon (zero-point energies and vibrational entropy) responses to spin-polarisation at the electrode surface. Electrochemical characterization of the THES in Ar-saturated 0.5 M KHCO3 solution on Au and Pt thin-film capped, ferromagnetic multi-layer (Pt/CoxBy/Ir) electrodes confirms increases of up to 30% for Pt (-0.15 V vs. RHE ), and over 95% suppression for Au (-0.5 V vs. RHE ), depending on the thickness of the catalytic cap [1]. The approach, understood to rest on proximity induced magnetism at the Pt and Au thin-films, opens new scalable avenues to circumvent scaling relations on existing electrocatalyst surfaces, which could be applied to a range of sustainable chemistry and energy applications.

[1] UKIPO Application No. 2415085.6 (14/10/2024)

This talk is part of the Lennard-Jones Centre series.

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• Hanchen DaDaDash
• Lennard-Jones Centre
• zoom.us/j/92447982065?pwd=RkhaYkM5VTZPZ3pYSHptUXlRSkppQT09

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