Chlorine Axial Coordination Activated Lanthanum Single Atoms for Efficient Oxygen Electroreduction with Maximum Utilization

Abstract Currently, there are still obstacles to rationally designing the ligand fields to activate rare‐earth (RE) elements with satisfactory intrinsic electrocatalytic reactivity. Herein, axial coordination strategies and nanostructure design are applied for the construction of La single atoms (La‐Cl SAs/NHPC) with satisfactory oxygen reduction reaction (ORR) activity. The nontrivial LaN₄Cl₂ motifs configuration and the hierarchical porous carbon substrate that facilitates maximized metal atom utilization ensure high half‐wave potential (0.91 V) and significant robustness in alkaline media. The aqueous and flexible Zinc‐air battery (ZAB) integrating La‐Cl SAs/NHPC as the cathode catalyst exhibits a maximum power density of 260.7 and 68.5 mW cm⁻², representing one of the most impressive RE‐based ORR electrocatalysts to date. Theoretical calculations have demonstrated that the Cl coordination evidently modulate the electronic structures of La sites, which promoted electron transfer efficiency by d‐p orbital couplings. With enhanced electroactivity of La sites, the adsorptions of key intermediates are optimized to alleviate the energy barriers of the potential‐determining step. Importantly, this preparation strategy is also successfully applied to other REs. This work provides perspectives for near‐range electronic structure modulation of RE‐SAs based on a nonplanar coordination micro‐environment for efficient electrocatalysis.