Platinum Terpyridine Metallopolymer Electrode as Cost-Effective Replacement for Bulk Platinum Catalysts in Oxygen Reduction Reaction and Hydrogen Evolution Reaction

Conducting polymers consisting of metal-selective coordination units and a highly conductive backbone, so-called metallopolymers, are interesting materials exposing single atoms for photo/electrocatalysis and thus represent a potential low-cost alternative for bulk or nanoparticulate platinum group metals (PGMs). We synthesized and fully characterized an electropolymerisable monomer bearing a pendant terpyridine unit for the selective complexation of PGMs. Electrocatalytic tests of the resulting metallopolymer, poly-[(tThTerpy)PtCl]Cl, revealed activity both in the oxygen reduction reaction and hydrogen evolution reaction. Rotating disk experiments showed the direct four-electron reduction of molecular oxygen to water at low angular velocities of the rotating electrode. Furthermore, the fabrication of Pt metallopolymers proved to be simple, nonhazardous and versatile. This proof-of-concept opens up the possibility for developing future low-cost electro- and photocatalysts to replace current systems.