Polyacrylate modified Cu electrode for selective electrochemical CO reduction towards multicarbon products.

Highly selective production of value-added multicarbon (C) products via electrochemical CO reduction reaction (eCORR) on polycrystalline copper (Cu) remains challenging. Herein, the facile surface modification using poly (α-ethyl cyanoacrylate) (PECA) is presented to greatly enhance the C selectivity for eCORR over polycrystalline Cu, with Faradaic efficiency (FE) towards C products increased from 30.1% for the Cu electrode to 72.6% for the obtained Cu-PECA electrode at -1.1 V vs. reversible hydrogen electrode (RHE). Given the well-determined FEs towards C products, the partial current densities for C production could be estimated to be -145.4 mA cm for the Cu-PECA electrode at -0.9 V vs. RHE in a homemade flow cell. In-situ spectral characterizations and theoretical calculations reveal that PECA featured with electron-accepting -C≡N and -COOR groups decorated onto the Cu electrode could inhibit the adsorption of *H intermediates and stabilize the *CO intermediates, given the redistributed interfacial electron density and the raised energy level of d-band center (E) of Cu active sites, thus facilitating the C-C coupling and then the C selective production. This study is believed to be guidable to the modification of electrocatalysts and electrodes with polymers to steer the surface adsorption behaviors of reaction intermediates to realize practical eCORR towards value-added C products with high activity and selectivity.