Curvature-induced Zn 3d Electron Return on Zn−N₄ Single-atom Carbon Nanofibers for Boosting Electroreduction of CO₂

The electrochemical CO₂ reduction to desired chemical feedstocks is of importance, yet it is still challenging to obtain high production selectivity with low overpotential at a current density surpassing the industry benchmark of 100 mA cm⁻². Herein, we constructed a low-cost Zn single-atom anchored on curved N-doped carbon nanofibers (Zn SAs/N−C) by a facile noncovalent self-assembly approach. At a low overpotential of only 330 mV, the Zn SAs/N−C exhibited simultaneously both a high current density up to 121.5 mA cm⁻² and a CO FE of 94.7 %, superior to the previous reports. Experiments and DFT calculations revealed that the Zn atoms in Zn−N₄ acted as the active sites, while adjacent pyridine-N coupled with Zn−N₄ could synergistically decrease the free energy barrier for intermediate *COOH formation. Importantly, the curvature of catalyst induced Zn 3d electrons that were bound to the Zn−N bonds to return to Zn atom, thereby leading to an increase in electron density of Zn and accelerating CO₂ electroreduction to CO.