Atomistic Distribution of Iron and Copper in Coordination Metallopolymer for Highly Efficient and Stable Hydrogen Evolution in Protic Media

Multifunctional aromatic linker ligands are crucial for designing robust heterogeneous electrocatalytic systems with an effective surface distribution of atomic redox active sites. Herein, we report the chemical immobilization of hetero-metal ions (Fe and Cu) containing metallopolymers on copper surface as a low overpotential and stable electrocatalyst in acidic electrolyte. The sulfur and nitrogen-rich triazine trithiolate ligand enables the active sites atomistic distribution through coordination linkage and displays an impressive low overpotential of −94 mV vs. RHE to attain −10 mA cm⁻² in 0.5 M H₂SO₄. It is almost 10³ times higher hydrogen evolution current densities than the copper substrate. The increased iron content and activation in acidic electrolyte reduce the overpotential and increase the electrochemical active surface area and catalytic activity. The long-term hydrogen evolution suggests excellent stability in strong acidic electrolytes, and the film remains adherent to the substrate at higher hydrogen evolution current densities of −500 mA cm⁻² and −700 A gm⁻¹.