Crafting fast and efficient H2 evolution electrocatalysts with tactical inclusion of nucleobases

Abstract

In order to achieve a hydrogen-driven energy infrastructure that is carbon-neutral, it is imperative that there be a synthetic catalyst that is developed from a non-noble metal. The unique interplay between the abundant transition metal containing an active site and the surrounding protein-based outer coordination sphere (OCS) is the essence of the remarkable H2 production displayed by hydrogenase enzymes. Here, we report a series of biomimetic cobalt complexes [Co(dimethylglyoxime)2(Nnucleobase derivative)Cl] crafted by strategic incorporation of a nucleobase and its derivatives (adenine, adenosine, adenosine monophosphate and hypoxanthine) around a common template. The nucleoside- and nucleotide-appended complexes electrocatalyze H2 evolution from neutral aqueous solutions at a rapid rate (turnover frequencies of ~13 000 and ~12000 s-1, respectively) while operating at an overpotential of <400 mV. The intricate proton exchange network created between the different fractions of nucleobase derivatives is one of the prime reasons behind such fast and energy-efficient catalysis.