Regulating the Local Coordination of Cd-Glutamate Through Ligand Chirality for Efficient Alkaline Hydrogen Evolution

The rational regulation of local coordination environments in metal-organic complexes provides an effective strategy for tuning electrocatalytic activity; however, the influence of ligand chirality on hydrogen evolution remains largely unexplored. Herein, we report a series of optically active Cd-glutamate coordination complexes synthesized from D-, L-, and racemic DL-glutamate ligands and systematically investigate how ligand stereochemistry governs their structural organization and alkaline hydrogen evolution reaction (HER) performance. Density functional theory (DFT) identifies an oxygen-coordinated Cd-glutamate configuration as the thermodynamically preferred structure, while comprehensive characterization supports that ligand chirality subtly modulates the local coordination symmetry, morphology, and electronic environment without altering the Cd²⁺ oxidation state. Electrochemical measurements reveal that the D-derived complex exhibits the highest HER activity compared to the L and DL counterparts, delivering a low overpotential of 188 mV at 10 mA cm^-2 with a Tafel slope of 148 mV dec^-1, together with the lowest charge-transfer resistance and excellent long-term electrochemical stability. Comparative DFT calculations further indicate that ligand chirality and the HOMO-LUMO gap alone do not directly account for the enhanced HER activity of D1, suggesting that its superior performance arises from the combined effects of chirality-dependent local coordination, structural organization, morphology, and interfacial properties.