Zwitterionic polymer-assisted asymmetrically coordinated Cu atoms on aligned carbonous microchannels for efficient electroreduction of CO2 to CO

Abstract

The synergetic optimization of atomically active site coordination and matrix microstructure is pivotal for rationally designing high performance electrocatalysts toward CO₂ reduction reaction (CO₂RR). Compared with other 3d transition metals, fully-filled 3d Cu single-atom (SA) electrocatalysts suffer from inferior performance with higher energy barriers and unsatisfactory adsorption towards key intermediates. Herein, asymmetrical Cu_SA–N₄S₁ coordination active sites embedded in well-aligned hierarchical nanocarbon are prepared by directional freezing a zwitterionic polymer-modified P(AM-co-DMAPS) (PADS) hydrogel, followed by pyrolyzing. The as-synthesized single Cu atoms supported on alighted hierarchical porous nanocarbons (Cu_SA@AHPC) exhibit an excellent FE(CO₂-to-CO) of 96.11% at −0.6V_RHE and robust durability over 80 h. Theoretical calculations and in situ spectroscopy reveal that the electron redistribution effectivity facilitated the formation of *COOH key intermediate, stabilized its adsorption and lowered the energy barriers. Notably, the carbonous microchannels successfully enhance CO₂ adsorption, promote the transfer of reactants and facilitate the rapid removal of gaseous products, especially at larger current densities, thus promoting the CO pathway activity. This study offers a new strategy to anchor and optimize SAs’ coordination, proposing perspectives on the simultaneous modulation of active sites and the supporting matrix toward superior CO₂RR performance.