Non-Bonding Interaction of Neighboring Fe and Ni Single-Atom Pairs on MOF-Derived N-Doped Carbon for Enhanced CO₂ Electroreduction

Single-atom catalysts (SACs), featuring high atom utilization, have captured widespread interests in diverse applications. However, the single-atom sites in SACs are generally recognized as independent units and the interplay of adjacent sites is largely overlooked. Herein, by the direct pyrolysis of MOFs assembled with Fe and Ni-doped ZnO nanoparticles, a novel Fe₁-Ni₁-N-C catalyst, with neighboring Fe and Ni single-atom pairs decorated on nitrogen-doped carbon support, has been precisely constructed. Thanks to the synergism of neighboring Fe and Ni single-atom pairs, Fe₁-Ni₁-N-C presents significantly boosted performances for electrocatalytic reduction of CO₂, far surpassing Fe₁-N-C and Ni₁-N-C with separate Fe or Ni single atoms. Additionally, the Fe₁-Ni₁-N-C also exhibits superior performance with excellent CO selectivity and durability in Zn-CO₂ battery. Theoretical simulations reveal that, in Fe₁-Ni₁-N-C, single Fe atoms can be highly activated by adjacent single-atom Ni via non-bonding interaction, significantly facilitating the formation of COOH* intermediate and thereby accelerating the overall CO₂ reduction. This work supplies a general strategy to construct single-atom catalysts containing multiple metal species and reveals the vital importance of the communitive effect between adjacent single atoms toward improved catalysis.