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submitted on 17.06.2019 and posted on 18.06.2019by Xi Yin, Ling Lin, Hoon T. Chung, Ulises Martinez, Andrew M. Baker, Sandipkumar Maurya, Piotr Zelenay
Finding a low-cost and stable electrocatalyst for hydrogen evolution reaction (HER) as a replacement for scarce and expensive precious metal catalysts has attracted significant interest from chemical and materials research communities. Here, we demonstrate an organic catalyst based on 2,2’-dipyridylamine (dpa) molecules adsorbed on carbon surface, which shows remarkable hydrogen evolution activity and performance durability in strongly acidic polymer electrolytes without involving any metal. The HER onset potential at dpa adsorbed on carbon has been found to be less than 50 mV in sulfuric acid and in a Nafion-based membrane electrode assembly (MEA). At the same time, this catalyst has shown no performance loss in a 60-hour durability test. The HER reaction mechanisms and the low onset overpotential in this system are revealed based on electrochemical study. Density functional theory (DFT) calculations suggest that the pyridyl-N functions as the active site for H adsorption with a free energy of -0.13 eV, in agreement with the unusually low onset overpotential for an organic molecular catalyst.
An earlier version of this manuscript was submitted to Science on January 12, 2018. A revised version was submitted to Nature Catalysis on March 22, 2019. The current version has been submitted to the Journal of the American Chemical Society on June 09, 2019.