Strain enhances the activity of molecular electrocatalysts via carbon nanotube supports

JJ Su and CB Musgrave and Y Song and LB Huang and Y Liu and G Li and YE Xin and P Xiong and MMJ Li and HR Wu and MH Zhu and HM Chen and JY Zhang and HC Shen and BZ Tang and M Robert and W III Goddard and RQ Ye, NATURE CATALYSIS, 6, 818-828 (2023).

DOI: 10.1038/s41929-023-01005-3

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.

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