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

Abstract

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.

Incorporation of Ruthenium Ions into Nanometer-Thick Films of Copper Sulfide by Anodization for Proton-Coupled Electron Transfer Reactions

“…Incessant efforts have been devoted to the search for acid-stable electrocatalysts that can replace costly and scarce platinum for electrochemical hydrogen production and hydrogen oxidation. Various materials based on transition-metal phosphides, nitrides, carbides, sulfides, metal–organic frameworks, and metallopolymers were explored for hydrogen evolution reactions with relatively good stability in acidic electrolytes. − Among these, transition-metal sulfide (TMS)-based electrocatalysts are extensively investigated for hydrogen evolution reactions due to their high exchange current density, stability in a wide pH range, abundant active sites, and tunable electrochemical properties. ,− …”

Bismuth(III) Coordination Linkage with Dimercaptothiadiazole: A p-Type Metallopolymer Photocathode Stable in Protic Electrolytes

“…15−17 Especially, the proton relay sites at ligands which are structurally positioned in the secondary coordination sphere of the redox-active metal centers could favor multiple proton− electron transfer in electrocatalytic reactions. 18,19 This enables the fast transfer or exchange of protons to the local redoxactive sites, which is essential for m-PCET. The polydentate functional ligand systems that are rich in N and S in the backbone have obtained interest in coordination photoelectrocatalysts.…”

“…Recently, coordination molecular complexes, metal–organic polymers, and metallo-organic frameworks have been widely investigated for diverse applications due to their tunable structural and electronic properties. , The coordination structures with two- and three-dimensional networks could provide an efficient charge transfer from metals to ligands and vice versa and utilize the photoredox activity. ,, Notably, the charge trapping and recombination of photogenerated excitons can be minimized while using metal-incorporated coordination polymers. ,,, Recently, functional organic ligands with linker units have been explored for the development of photoactive coordination molecular systems. ,,, Metal ions incorporated with highly functionalized ligands have been explored for various applications. − Especially, the proton relay sites at ligands which are structurally positioned in the secondary coordination sphere of the redox-active metal centers could favor multiple proton–electron transfer in electrocatalytic reactions. , This enables the fast transfer or exchange of protons to the local redox-active sites, which is essential for m-PCET. The polydentate functional ligand systems that are rich in N and S in the backbone have obtained interest in coordination photoelectrocatalysts. ,− In our previous reports, triazine trithiolate and dimercaptothiadiazole being the functional ligands can form highly cross-linked coordination network structures and provide good charge transport. ,, …”