Abstract
Proton activity at the electrified interface is central to the kinetics of proton-coupled electron transfer (PCET) reactions for making chemicals and fuels. Here we employ a library of protic ionic liquids in an interfacial layer on platinum and gold to alter local proton activity, where the intrinsic oxygen-reduction reaction (ORR) activity is enhanced up to fivefold, exhibiting a volcano-shaped dependence on the pKa of the ionic liquid. The enhanced ORR activity is attributed to strengthened hydrogen bonds between ORR products and ionic liquids with comparable pKas, resulting in favourable PCET kinetics. This proposed mechanism is supported by in situ surface-enhanced Fourier-transform infrared spectroscopy and our simulation of PCET kinetics based on computed proton vibrational wavefunctions at the hydrogen-bonding interface. These findings highlight opportunities for using non-covalent interactions between hydrogen-bonded structures and solvation environments at the electrified interface to tune the kinetics of ORR and beyond.
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Data availability
The data supporting the findings of this study are available in the paper and its Supplementary Information. Extra data are available from the corresponding authors on reasonable request.
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Acknowledgements
This work was supported in part by the Toyota Research Institute through the Accelerated Materials Design and Discovery programme and the Skoltech-MIT Center for Electrochemical Energy. We thank Professor Zhong-Qun Tian from Xiamen University for fruitful discussion. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant no. ACI-154856283. This research also used resources of the National Energy Research Scientific Computing Center (NERSC); a DOE Office of Science User Facility supported by the Office of Science of the US DOE under contract no. DE-AC02-05CH11231. T.W. was supported by financial support from the National Natural Science Foundation of China (grant 21875194) and the China Scholarship Council.
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Contributions
Y.S.-H. and T.W conceived the idea and designed the experiments. T.W. carried out experiments on catalyst synthesis, electrocatalytic tests and data analysis. Y.Z. and T.W. performed the in situ surface-enhanced FTIR spectroscopy measurements. Y.Z. and T.W performed the DFT calculations and analysis. T.W. and B.H. analysed the electrochemical data. B.C. synthesized nanoparticles. R.R.R., L.G. and S.-G.S. participated in the discussion and interpretation of experimental and theoretical data. Y.S.-H. and T.W. wrote the manuscript. All of the authors discussed the results and commented on the manuscript.
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Peer review information Nature Catalysis thanks Sharon Hammes-Schiffer and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Supplementary information
Supplementary Information
Supplementary methods, Figs. 1–29, Tables 1–11, and notes 1 and 2.
Supplementary Data 1
Atomic coordinates of optimized structure of MTBD-OH.
Supplementary Data 2
Atomic coordinates of optimized structure of DEMA-OH.
Supplementary Data 3
Atomic coordinates of optimized structure of C4Him-OH.
Supplementary Data 4
Atomic coordinates of optimized structure of MTBD-H2O.
Supplementary Data 5
Atomic coordinates of optimized structure of MTBD-OOH.
Supplementary Data 6
Atomic coordinates of optimized structure of DEMA-OOH.
Supplementary Data7
Atomic coordinates of optimized structure of C4Him-OOH.
Supplementary Data 8
Atomic coordinates of optimized structure of DEMA-HOOH.
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Wang, T., Zhang, Y., Huang, B. et al. Enhancing oxygen reduction electrocatalysis by tuning interfacial hydrogen bonds. Nat Catal 4, 753–762 (2021). https://doi.org/10.1038/s41929-021-00668-0
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DOI: https://doi.org/10.1038/s41929-021-00668-0
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