Selective CO2 Electrochemical Reduction Enabled by a Tricomponent Copolymer Modifier on a Copper Surface

• Published in: Journal of the American Chemical Society 2021-02, Vol.143 (7), p.2857-2865
• Main Authors: Wang, Jianchun, Cheng, Tao, Fenwick, Aidan Q, Baroud, Turki N, Rosas-Hernández, Alonso, Ko, Jeong Hoon, Gan, Quan, Goddard III, William A, Grubbs, Robert H
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.0c12478

Electrochemical CO2 reduction over Cu could provide value-added multicarbon hydrocarbons and alcohols. Despite recent breakthroughs, it remains a significant challenge to design a catalytic system with high product selectivity. Here we demonstrate that a high selectivity of ethylene (55%) and C2+ products (77%) could be achieved by a highly modular tricomponent copolymer modified Cu electrode, rivaling the best performance using other modified polycrystalline Cu foil catalysts. Such a copolymer can be conveniently prepared by a ring-opening metathesis polymerization, thereby offering a new degree of freedom for tuning the selectivity. Control experiments indicate all three components are essential for the selectivity enhancement. A surface characterization showed that the incorporation of a phenylpyridinium component increased the film robustness against delamination. It was also shown that its superior performance is not due to a morphology change of the Cu underneath. Molecular dynamics (MD) simulations indicate that a combination of increased local CO2 concentration, increased porosity for gas diffusion, and the local electric field effect together contribute to the increased ethylene and C2+ product selectivity.