Understanding hydrogen electrocatalysis by probing the hydrogen-bond network of water at the electrified Pt–solution interface
Abstract
Rational construction of the electrode–solution interface where electrochemical processes occur is of paramount importance in electrochemistry. Efforts to gain better control and understanding of the interface have been hindered by lack of probing methods. Here we show that the hydrogen evolution and oxidation reactions (HER/HOR) catalysed by platinum in base can be promoted by introduction of N-methylimidazoles at the platinum–water interface. In situ spectroscopic characterization together with simulations indicate that the N-methylimidazoles facilitate diffusion of hydroxides across the interface by holding the second layer of water close to platinum surfaces, thereby promoting the HER/HOR. We thus propose that the HER/HOR kinetics of platinum in acid and base is governed by diffusion of protons and hydroxides, respectively, through the hydrogen-bond network of interfacial water by the Grotthuss mechanism. Moreover, we demonstrate a 40% performance improvement of an anion exchange membrane electrolyser by adding 1,2-dimethylimidazole into the alkali fed into its platinum cathode.
Additional Information
© 2023 Springer Nature Limited. This work was supported by the Office of Naval Research (ONR) grant N000141712608 (Q.J.). This research used beamline 7-BM (QAS) of the National Synchrotron Light Source II, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory Contract DE-SC0012704. Beamline operations were supported in part by the Synchrotron Catalysis Consortium Grant DE-SC0012335. W.A.G. acknowledges support by the Liquid Sunlight Alliance, which is supported by the US DOE, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under award number DE-SC0021266. This work used the Extreme Science and Engineering Discovery Environment (XSEDE) for AIMD simulation, which is supported by the NSF grant number ACI-1548562. S.K. acknowledges support from the Resnick Sustainability Institute at Caltech. Contributions: Q.J. conceived the project, designed the experiments and proposed the HER/HOR mechanism. Q.S. conducted the electrochemical experiments and the data analysis in S.M.'s lab partly under his supervision. S.T. and J.J.G. conducted the NMR experiments and analysed the data. Q.S. helped to prepare the NMR samples. S.K. and W.A.G. planned the AIMD calculations. N.M. and S.A.L. performed the DFT calculations and contributed to the writing of the DFT computational results. Y.Y. and N.J.O. conducted the in situ ATR-SEIRAS and data analysis. Y.Y. and N.J.O. repeated electrochemical RDE experiments. Q.S., L.M. and S.N.E. conducted the XAS experiments, and Q.J. did the data analysis. J.L. conducted the in situ surface-enhanced Raman and data analysis. Q.S. and I.K. conducted the AEMEL testing and analysed the data. Q.J. supervised the project and data analysis. Q.J., Y.Y., W.A.G., Q.S., N.J.O. and S.K. wrote the paper and prepared the figures. The authors declare no competing interests.Attached Files
Supplemental Material - 41560_2023_1302_MOESM10_ESM.mp4
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Additional details
- Eprint ID
- 122462
- Resolver ID
- CaltechAUTHORS:20230725-856998000.32
- Office of Naval Research (ONR)
- N000141712608
- Department of Energy (DOE)
- DE-SC0012704
- Department of Energy (DOE)
- DE-SC0012335
- Department of Energy (DOE)
- DE-SC0021266
- NSF
- ACI-1548562
- Resnick Sustainability Institute
- Created
-
2023-08-14Created from EPrint's datestamp field
- Updated
-
2023-08-14Created from EPrint's last_modified field
- Caltech groups
- Liquid Sunlight Alliance, Resnick Sustainability Institute