A Ni(II) coordination polymer with dual electrochemical functions: synthesis, crystal structure, hydrogen evolution reaction and l-ascorbic acid sensing

Abstract A two-dimensional Ni(II) coordination polymer (NiCP) of the formula {[NiL(terephthalate)(H 2 O) 2 ]·2H 2 O} n (L = bis(1-(pyridin-4-ylmethyl)-benzimidazol-2-ylmethyl)ether), has been obtained from a solvothermal reaction, and characterized by single-crystal X-ray diffraction, elemental analysis, and IR and UV/Vis spectra. The coordinated terephthalate anions and the L ligands connect the Ni(II) ions in two directions, resulting in the construction of a corrugated layered structure. The electrochemical properties of a NiCP-CPE composite electrode supported by this coordination polymer were studied. For the electrocatalytic hydrogen evolution reaction, the required overpotential of this electrode (NiCP-CPE) is −521 mV when the current density reaches 10 mA cm −2 . Compared with the solid carbon paste electrode (sCPE, −976 mV), the smaller overpotential proves effective electrocatalysis of the coordination polymer of the hydrogen evolution reaction. The doped electrode also exhibits high-efficiency in the electrochemical sensing of l -ascorbic acid in water, showing a detection limit of 0.28 μM in a linear range of 0.4–4000 μM.