Strain enhances the activity of molecular electrocatalysts via carbon nanotube supports
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1.
California Institute of Technology
Abstract
Support-induced strain engineering is useful for modulating the properties of two-dimensional materials. However, controlling strain of planar molecules is technically challenging due to their sub-2 nm lateral size. Additionally, the effect of strain on molecular properties remains poorly understood. Here we show that carbon nanotubes (CNTs) are ideal substrates for inducing optimum properties through molecular curvature. In a tandem-flow electrolyser with monodispersed cobalt phthalocyanine (CoPc) on single-walled CNTs (CoPc/SWCNTs) for CO₂ reduction, we achieve a methanol partial current density of >90 mA cm⁻² with >60% selectivity, surpassing wide multiwalled CNTs at 16.6%. We report vibronic and X-ray spectroscopies to unravel the distinct local geometries and electronic structures induced by the strong molecule–support interactions. Grand canonical density functional theory confirms that curved CoPc/SWCNTs improve *CO binding to enable subsequent reduction, whereas wide multiwalled CNTs favour CO desorption. Our results show the important role of SWCNTs beyond catalyst dispersion and electron conduction.
Copyright and License
© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Acknowledgement
R.Y. acknowledges support from the Guangdong Basic and Applied Basic Research Fund (2022A1515011333), the Hong Kong Research Grant Council (21300620, 11307120, 11309723), the State Key Laboratory of Marine Pollution (SKLMP/IRF/0029) and the Shenzhen Science and Technology Program (JCYJ20220818101204009 and 2021Szvup129). C.B.M. and W.A.G. acknowledge support from the Liquid Sunlight Alliance, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under award number DE-SC0021266. B.Z.T. acknowledges support from the Shenzhen Key Laboratory of Functional Aggregate Materials (ZDSYS20211021111400001) and the Science Technology Innovation Commission of Shenzhen Municipality (KQTD20210811090142053, JCYJ20220818103007014). We thank W. Zhai and L. Wang for help with Raman characterization, and W. Li for his assistance with high-resolution TEM imaging.
Contributions
These authors contributed equally: Jianjun Su, Charles B. Musgrave III.
R.Y. conceived and designed the research. R.Y., W.A.G. and B.Z.T. supervised the research. J.S. carried out most of the experiments and C.B.M. performed the calculations. Y.S., L.H., Y.L., G.L., Y.X., J.Z. and H.S. conducted part of the experiments. P.X., M.M.-J.L. and H.M.C. performed the X-ray absorption spectroscopy experiment and analysis. H.W. and M.Z. performed the in situ Fourier transform infrared studies. R.Y., W.A.G., J.S., C.B.M. and M.R. analysed the data and wrote the manuscript with input from the other authors.
Data Availability
All data are available from the authors upon reasonable request.
Conflict of Interest
The authors declare no competing interests.
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Additional details
- University Grants Commission
- 21300620
- University Grants Committee
- 11307120
- University Grants Commission
- 11309723
- United States Department of Energy
- DE-SC0021266
- Caltech groups
- Liquid Sunlight Alliance