Polyacrylate modified Cu electrode for selective electrochemical CO₂ reduction towards multicarbon products

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (eCO2RR) to multicarbon (C2+) products on copper is crucial but challenging for selectivity.
• Polycrystalline copper (Cu) often suffers from low C2+ selectivity in eCO2RR.

Purpose of the Study:

• To enhance the selectivity of C2+ product formation during eCO2RR on polycrystalline Cu.
• To investigate the mechanism by which polymer modification influences eCO2RR selectivity.

Main Methods:

• Facile surface modification of polycrystalline Cu electrodes using poly(α-ethyl cyanoacrylate) (PECA).
• Electrochemical characterization including Faradaic efficiency (FE) measurements at various potentials.
• In-situ spectral characterizations and theoretical calculations to probe surface interactions and electronic properties.

Main Results:

• PECA modification increased C2+ selectivity FE from 30.1% to 72.6% at -1.1 V vs. RHE.
• Achieved high partial current densities for C2+ production (-145.4 mA cm-2 at -0.9 V vs. RHE).
• Demonstrated that PECA inhibits *H intermediates and stabilizes *CO intermediates via electronic redistribution and d-band center elevation.

Conclusions:

• PECA surface modification effectively steers eCO2RR towards high C2+ selectivity on Cu electrodes.
• The mechanism involves altered adsorption of intermediates due to PECA's electron-withdrawing groups and modified electronic structure of Cu.
• This polymer-based electrode modification strategy offers a promising route for practical eCO2RR to value-added chemicals.