Dinuclear Copper Complex for High‐Rate Hydrogen Evolution Under Neutral Aqueous Conditions

The development of an efficient and stable electrocatalyst for the hydrogen evolution reaction (HER), based on earth‐abundant components, represents a crucial step toward cost‐effective and environmentally friendly hydrogen production. This study presents the utilization of a dinuclear copper catalyst, denoted as [Cu‐Gly‐SB] (Complex 1), for HER under both aqueous and non‐aqueous conditions. In non‐aqueous settings, the catalyst achieves excellent HER performance, requiring only a 270 mV overpotential when acetic acid is used as the proton donor. Notably, in fully aqueous conditions, complex 1 attains a remarkable current density of 18.8 mA ⋅ cm−2 at −0.7 V vs. RHE in cyclic voltammetry. The kobs value of ≈2.7×104 s−1 in aqueous solution at pH 7.0 further underlines the superior catalytic performance of 1, outperforming most non‐noble‐metal molecular catalysts functioning in fully aqueous solutions. The robust stability of 1 is demonstrated through controlled potential electrolysis (CPE) over a span of 48 hours, achieving an impressive catalytic current of 11.0 mA ⋅ cm−2 at −0.39 V. Moreover, the catalytic current gradually increases with higher reduction potentials, reaching a substantial 100 mA ⋅ cm−2 at an overpotential of 590 mV during CPE >48 hours. Thorough characterizations further confirm the molecular nature of the catalyst. Copper Glycine Schiff Base Catalyst: Mimicking natural processes, this dinuclear copper catalyst with a Schiff base ligand efficiently catalyzes HER from neutral water, showcasing remarkable rate and stability. It reaches ~19 mA cm−2 at −0.7 V vs. RHE (ic/ip=166), corresponding to a kobs of ~27,000 s−1, one of the highest TOFs for an earth‐abundant molecular catalyst under similar coditions.