Professor Patrick Unwin, Department of Chemistry, University of Warwick, UK

Correlative Electrochemical Multi-Microscopy: Nanoscale Measurements Facilitate a Multiscale Understanding of Electrochemical Processes and Interfaces
Electrodes of practical importance are usually complex on a range of length scales, from the nanoscale to the device level. To deepen understanding of electrochemical processes, we have invented new techniques – primarily scanning electrochemical cell microscopy (SECCM) - that enable quantitative visualisation of nanoscale electrode activity in the form of activity maps and activity movies.^1-10 These rich datasets are mapped onto co-located electrode structure and properties from complementary high-resolution microscopy and spectroscopy techniques. With this approach, complex electrode surfaces are studied as set of “single entities” (e.g., individual steps, terraces, defects, crystal facets, grain boundaries, single particles).^1,5 The resulting detailed microscopic information is used to predict and test the behaviour of electrodes on larger length scales. In this presentation, I will address the question: what can learn about electrochemical systems from a multiscale approach?

A wide range of illustrative examples of this general philosophy includes investigations of 1D and 2D materials, single particles and ensembles of particles on electrode supports, as well as structurally and/or compositionally heterogeneous surfaces, such as polycrystalline metals and polymer composite electrodes. Applications include electrocatalysis, battery electrodes, next generation membranes and corrosion. Ultimately, the approaches we advocate provide a roadmap to facilitate the rational design of functional (electro)materials. The techniques and ideas can also be translated to other areas, from crystallisation to studies of living cells at the nanoscale.

I am grateful to many members of the Warwick Electrochemistry & Interfaces Group and our many collaborators who have contributed to our work in this area and will be acknowledged throughout this lecture.

References
[1] D. Martín-Yerga, D. C. Milan, X. Xu, J. Fernández-Vidal, L. Whalley, A. J. Cowan, L. J. Hardwick and P. R. Unwin, Angew. Chem. Int. Ed. 2022, 61, e202207184.
[2] R. G. Mariano, O. J. Wahab, J. A. Rabinowitz, J. Oppenheim, T. Chen, P. R. Unwin and M. Dinca, ACS Central Sci., 2022, 8, 975–982.
[3] O. J. Wahab, M. Kang, E. Daviddi, M. Walker and P. R. Unwin, ACS Catalysis, 2022, 12, 6578 - 6588.
[4] C. L. Bentley, M. Kang, S. Bukola, S. E. Creager and P. R. Unwin, ACS Nano, 2022, 16, 5233 - 5245.
[5] S.-X. Guo, C. L. Bentley, M. Kang, A. M. Bond, P. R. Unwin and J. Zhang, Acc. Chem. Res. 2022, 55, 241 - 251.
[6] D.-Q. Liu, M. Kang, D. Perry, C.-H. Chen, G. West, X. Xia, S. Chaudhuri, Z. P. L. Laker, N. R. Wilson, G. N. Meloni, M. M. Melander, R. J. Maurer and P. R. Unwin, Nature Comm., 2021, 12, (7110).
[7] J. T. Mefford, A. R. Akbashev, M. Kang, C. L. Bentley, W. E. Gent, H. D. Deng, D. H. Alsem, Y.-S. Yu, N. J. Salmon, D. A. Shapiro, P. R. Unwin, W. C. Chueh, Nature, 2021, 593, 67 - 73.
[8] R. G. Mariano, M. Kang, O. J. Wahab, I. J. McPherson, J. A. Rabinowitz, P. R. Unwin and M. W. Kanan, Nature Materials, 2021, 20, 1000 - 1006.
[9] C. L. Bentley, M. Kang, P. R. Unwin, J. Am. Chem. Soc., 2019, 141, 2179–2193.
[10] M. Kang, D. Momotenko, A. Page, D. Perry, P. R. Unwin, Langmuir, 2016, 32, 7993-8008.