Partial Disruption of Coordination Bonds Triggers MOF Amorphization for Efficient Electrocatalytic Nitrate Reduction to Ammonia

ABSTRACT Amorphous metal‐organic frameworks ( a ‐MOFs) hold great promise for expanding the functional and structural landscape of traditional MOFs, yet their fabrication and local structural investigations remain a significant challenge. Herein, we propose a partial coordination bond disruption strategy for preparing a ‐MOFs from mixed‐ligand complexes. The M 2 (trz) 2 sq family ( M = Co, Zn, Cd; trz = 1,2,4‐triazolate; sq = squarate) features two different types of linkage: stronger M–trz–M connections that assemble into a flexible “wine‐rack” framework, and comparatively weaker M–sq–M connections that act as the supporting pillars. A comprehensive analysis combining synchrotron‐based powder X‐ray diffraction, X‐ray absorption fine structure (XAFS) spectroscopy, pair distribution function (PDF) analysis, and density functional theory (DFT) calculations reveals that, under thermal dehydration, the M–sq–M linkages are selectively broken. Meanwhile, the wine‐rack M–trz–M framework undergoes geometric distortion, ultimately leading to the loss of long‐range order. Benefiting from the abundance of coordinatively unsaturated cobalt sites, the a ‐Co 2 (trz) 2 sq shows remarkable electrocatalytic performance toward the nitrate reduction reaction (NO 3 RR) to ammonia, achieving a Faraday efficiency (FE) of up to 96.32%. This work unambiguously reveals the synergistic effect of partial coordination disruption in mixed‐ligand MOFs, potentially opening a new avenue for the rational design of functional a ‐MOFs.