Bioinspired nickel‐cysteine‐methoxy polyethylene glycol metallopolymer water solubility and electrochemical properties

Abstract The exploitation of remarkable hydrogen evolution reaction (HER) catalysts that perform at rates comparable with that of platinum but utilize earth‐abundant metals in a green solvent (water) has garnered considerable interest. Inspired by enzymes, water‐soluble metallopolymers have recently emerged as highly promising HER catalysts, generally exhibiting high HER rates in aqueous solutions. However, challenges remain in the synthesis of metallopolymers and many artificial hydrogen evolution catalysts still rely on organic solvents. This study proposes incorporating water‐soluble methoxy polyethylene glycol at both ends of a nickel–cysteine metal complex through a classical esterification reaction. The resulting nickel metallopolymer demonstrates considerable water solubility (103.9 mg mL −1 ) under room temperature. Moreover, the stable metallopolymer exhibits an irreversible reduction peak between −0.6 and − 0.8 V, indicating HER activity in acidic and neutral environments. The excellent water solubility of this metallopolymer catalyst provides a basis for subsequent research and has practical applications in the field of HER catalysts.