Electrocatalytic hydrogen evolution with cobalt–poly(4-vinylpyridine) metallopolymers

A facile synthetic pathway using poly(4-vinylpyridine) as a polypyridyl platform is reported for the formation of a metallopolymer. Electrochemical studies indicate that the metallopolymer acts as an efficient H2 evolution catalyst similar to cobalt polypyridyl complexes. It is also observed that the metallopolymer is transformed to cobalt particles when a cathodic potential is applied in the presence of an acid. Electrochemical measurements indicate that an FTO electrode coated with these cobalt particles also acts as an efficient hydrogen evolution catalyst. Approximately 80 µmoles of H2 gas can be collected during 2 h of electrolysis at − 1.5 V (vs. Fc+/0) in the presence of 60 mM of acetic acid. A comprehensive study of the electrochemical and electrocatalytic behavior of cobalt-poly(4-vinylpyridine) is discussed in detail. Graphical Abstract: Poly(4-vinylpyridine) as a precursor for electrodeposited cobalt particles: a cobalt coat derived by a metallopolymer acts as an efficient H2 evolution catalyst. It can transform to a cobalt coat when a potential above − 1.1 V is applied in acid medium. Exchange current density of 10−2.67 mA cm−2 was observed from the Co-coat at − 1.5 V (vs. Fc+/0). Acknowledgements The authors thank the Science and Technology Council of Turkey, TUBITAK (Project No: 215Z249) for financial support. Emine Ülker thanks TUBITAK for support (Project No: 1929B011500059).