Copper-triggered delocalization of bismuth p-orbital favours high-throughput CO2 electroreduction.

At present, formic acid with the high energy value is the promising product generated by the large-scale renewable electricity-driven CO 2 conversion, yet challenges remain in the high-throughput and low-energy production accompanied by the considerable selectivity. Herein, in view of the contribution of electronic modulation to electrocatalytic CO 2 reduction reaction (CO 2 RR) activity of catalysts, the thin BiCu-bimetallic film was designed and built on Cu foam (BiCu/CF) by coupling a facile hydrothermal reaction and an immediate electrochemical transformation. The theoretical evidences demonstrate that Bi p -orbital delocalization triggered by the close-contact metal Cu optimizes reaction pathway of CO 2 RR, and also favours the orbital hybridization between Bi atom and *OCHO intermediate to form more anti-bonding orbitals, resulting in stabilizing *OCHO intermediate and lowering the thermodynamic barrier of CO 2 RR. Meanwhile, the electron transferred from catalyst-sites to reaction species also accelerates during CO 2 RR. Integrating the improved intrinsic activity of Bi catalytic-sites and the superiority of Cu foam in exposing more active sites and the mechanical strength, the BiCu/CF electrode with optimal thickness can acquire satisfactory indicators for industrial application, yielding a record formate current density of 856 mA cm−2, higher than 85% Faradic efficiency, along with a remarkable stability, which outperforms state-of-the-art Bi-based catalysts. This study offers potential avenues of engineering orbital delocalization to rationally construct advanced CO 2 RR electrodes for the carbon-neutral cycle and utilization. Cu-triggered Bi p -orbital delocalization favours the orbital hybridization between Bi catalytic-sites and *OCHO intermediate and also lowers the thermodynamic barrier of CO 2 reduction. Therefore, BiCu-bimetallic film on Cu foam yields delightful current densities of 1000 mA cm−2 with HCOOH FEs larger than 85% as well as the remarkable catalytic stability and reproducibility, which are closer to the industrial demand. [Display omitted] • The optimal BiCu/CF yields a record formate current density of 856 mA cm−2 along with higher than 85% Faradic efficiency. • The delocalized Bi p -orbitals triggered by metal Cu reduce the thermodynamic and dynamic barrier of CO 2 reaction. • It is opening up a new perspective for engineering p -orbital delocalization of main-group metals. [ABSTRACT FROM AUTHOR]