Bio-Inspired Polydopamine Mimic Noble Metal Electrocatalysts in Hydrogen Evolution Reaction

Abstract

The main electrocatalysts for the electrochemical hydrogen evolution reaction (HER) rely on platinum due to high efficiencies, low binding energy for hydrogen and high electroactive-site density, however the cost of platinum is a crucial limitation for the production of hydrogen by this rare metal.[1] Here, we establish a metal-free and bio-organic electrocatalyst platform that resembles the platinum surface by incorporating hydrogen-affine hydrogen bonds. We introduce keto-amine functional motifs, which act as selective reaction centres.[2, 3] The keto-amine-functionalized biopolymer shown in this work evolve hydrogen at the lowest overpotential in a non-metallic system. With excellent electrochemical stability and chemical robustness, we are able to present a scale-up continuous-flow electrolysis and produce 1 L net molecular hydrogen within less than 9 hours using 2.3 mg of biopolymer electrocatalyst.[1] Y. Zheng, Y. Jiao, Y. Zhu, L.H. Li, Y. Han, Y. Chen, A. Du, M. Jaroniec, S.Z. Qiao, Hydrogen evolution by a metal-free electrocatalyst, Nature Communications, 5 (2014) 3783.[2] H. Coskun, A. Aljabour, P. De Luna, D. Farka, T. Greunz, D. Stifter, M. Kus, X.L. Zheng, M. Liu, A.W. Hassel, W. Schofberger, E.H. Sargent, N.S. Sariciftci, P. Stadler, Biofunctionalized conductive polymers enable efficient CO2 electroreduction, Science Advances, 3 (2017).[3] H. Coskun, A. Aljabour, L. Uiberlacker, M. Strobel, S. Hild, C. Cobet, D. Farka, P. Stadler, N.S. Sariciftci, Chemical vapor deposition - based synthesis of conductive polydopamine thin-films, Thin Solid Films, 645 (2018) 320-325.