Strain enhances the activity of molecular electrocatalysts via carbon nanotube supports

14 Aug 2023

Published on nature catalysis (14 August 2023)

Author(s): Jianjun Su, Charles B. Musgrave III, Yun Song , Libei Huang , Yong Liu , Geng Li , Yinger Xin , Pei Xiong , Molly Meng-Jung Li , Haoran Wu , Minghui Zhu , Hao Ming Chen , Jianyu Zhang , Hanchen Shen , Ben Zhong Tang , Marc Robert , William A. Goddard III & Ruquan Ye

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.

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