Synergistic Effect of Atomically Dispersed Ni–Zn Pair Sites for Enhanced CO₂ Electroreduction

Dual-atom catalysts have the potential to outperform the well-established single-atom catalysts for the electrochemical conversion of CO₂. However, the lack of understanding regarding the mechanism of this enhanced catalytic process prevents the rational design of high-performance catalysts. Herein, an obvious synergistic effect in atomically dispersed Ni–Zn bimetal sites is observed. In situ characterization combined with density functional theory (DFT) calculations reveals that heteronuclear coordination modifies the d-states of the metal atom, narrowing the gap between the d-band centre (ε_d) of the Ni (3d) orbitals and the Fermi energy level (E_F) to strengthen the electronic interaction at the reaction interface, resulting in a lower free energy barrier (ΔG) in the thermodynamic pathway and a reduced activation energy (E_a) as well as fortified metal–C bonding in the kinetic pathway. Consequently, a CO faradaic efficiency of >90% is obtained across a broad potential window from −0.5 to −1.0 V (vs RHE), reaching a maximum of 99% at −0.8 V, superior to that of the Ni/Zn single-metal sites.