The Ni─Cl─Ni Sites Bridged by Chlorine to Stabilize Short‐Range Order in Nickel Complex for Amorphous Electrocatalysts

Abstract Amorphous catalysts have shown great promise for electrocatalysis due to their unique short‐range ordered structures, which allow performance optimization through structural engineering. However, inadequate structural collapse during crystalline‐amorphous transformations compromises coordination environment retention and impedes understanding of structure‐property/performance correlations in disordered amorphous catalysts/materials. In this study, we ingeniously introduced a chloro‐bridging structure, which successfully preserves the µ₂─Cl bridging motif in the nickel complex precursor (Ni₂(µ₂─Cl)(HL)₂(CH₃OH)(H₂O)Cl). This achievement enables the synthesis of a highly stable amorphous catalyst, a‐250‐I, featuring an enhanced short‐range order. Through comprehensive experimental and computational investigations, it is discovered that the remarkable activity enhancement can be ascribed to the dynamic transition from μ₂─Cl to μ₂─O bridging at the nickel site. This transformation elegantly tunes the d‐orbital energy levels to lower values, unleashing a cascade of effects that accelerate the reaction kinetics and catapult the electrocatalytic performance to new heights. At 10 mA·cm⁻² current density, the optimized a‐250‐I catalyst achieves low overpotentials of 1.47 V (OER) and 1.36 V (UOR), showcasing robust stability with dual‐functional catalytic capability. This strategy offers a controllable way to stabilize the short‐range ordering of amorphous catalysts for enhancing catalytic activity by modulating the electronic structure through local bridge coordination.