A Bis(thiosemicarbazonato)‐zinc Complex, an Electrocatalyst for Hydrogen Evolution and Oxidation Via Ligand‐assisted Metal‐centered Reactivity

Based on that hydrogen energy is widely used in fuel cells, the design and research of new catalysts for both hydrogen evolution reactions (HERs) and hydrogen oxidation reactions (HORs) are becoming increasingly important. A new catalyst for both hydrogen evolution and oxidation, based on a zinc complex, [Zn-ATSE](2), is designed and provided by the reaction of Zn (CH3CO2)(2) with diacetyl-2-(4-N-ethyl-3-thiosemicarbazone)-3-(4-N-amino-3-thiosemicarbazone) (H(2)ATSE) in our group. Electrochemical investigations show that [Zn-ATSE](2) can electro-catalyze hydrogen evolution from acetic acid with a turnover frequency (TOF) of 64 mol H-2 mol catalyst(-1) h(-1) under an overpotential of 914.6 mV. Moreover, [Zn-ATSE](2) also can electro-catalyze hydrogen oxidation with a TOF of 13.52 s(-1). The results can be attributed to the hydrazine group of [Zn-ATSE](2) that can form a ligand-based radical species. Possible electrocatalytic cycles for H-2 production and oxidation by [Zn-ATSE](2) are afforded. We hope these findings can afford a new method for the design of electrocatalysts for both H-2 evolution and H-2 oxidation.