Rigidity‐Flexibility Integrated Porous Coordination Polymers via Lattice‐Confined Adaptive Evolution for Efficient Neutral Nitrate Reduction to Ammonia

ABSTRACT

Adaptive catalytic systems hold significant potential for designing electrocatalysts with both high activity and stability. However, achieving a balance between structural robustness and dynamic adaptability remains challenging. Herein, we report a new design strategy for self‐adaptive electrocatalysts for boosting the electrosynthesis of ammonia by integrating a rigid framework with flexible coordination bonds within a porous coordination polymer (PCP). A rigid‐flexible coupling copper pyrazole‐based PCP, referred to as Cu‐pyNDI, is designed to function as a self‐adaptive electrocatalyst that exhibits both structural robustness and dynamic adaptability. Operando x‐ray absorption spectroscopy (XAS) reveals that during the reaction, the copper sites in Cu‐pyNDI undergo reversible local structural restructuring, resulting in the formation of lower‐valence Cu, which serves as potentially active species. Building on the operando XAS findings, we introduced iron doping into Cu‐pyNDI to modulate the self‐regulating behavior of copper by enhancing the formation of low‐valence copper species with lower coordination numbers, which serve as potential active centers, thereby facilitating the generation of the *NO ₂ intermediate. Consequently, Fe _0.25 Cu _0.75 ‐pyNDI demonstrated improved electrocatalytic performance, achieving a Faradaic efficiency of 93% and an ammonia yield of 18847 µg h ⁻¹ mg _cat ⁻¹ in neutral electrolytes, comparable to state‐of‐the‐art electrocatalysts.