Tunability of Nickel Benzenehexathiolate Electrocatalysts for the Hydrogen Evolution Reaction

Dithiolene-based coordination polymers synthesized using earth-abundant transition metals have been rigorously explored for sustainable energy applications, such as solar-to-fuel conversion. The strategy of embedding molecular catalysts into extended frameworks is expected to improve the catalytic performance and reusability of the catalysts. Here, we investigate nickel benzenehexathiolate (<b>NiBHT</b>) frameworks as electrocatalysts to facilitate the hydrogen evolution reaction (HER) in acidic aqueous conditions. <b>NiBHT</b> coordination polymers synthesized with different morphologies and porosity were investigated to determine the essential features for developing efficient electrocatalysts for HER. The nonporous <b>NiBHT</b> coordination polymer in nanoparticle morphology exhibited enhanced electrochemical activity with an onset potential of -128 mV and an overpotential of 225 mV at 10 mA/cm². The 2 h controlled potential electrolysis of this electrocatalyst achieved a Faradaic efficiency of 90%, suggesting that the dithiolene-based electrode materials containing nickel ions are an efficient electrocatalyst for the hydrogen evolution reaction.