Electrooxidation of Toxic Sulfite Material Using Ni-Ru-Based Heterometallo Supramolecular Polymer as Electrocatalyst: Synthesis and Kinetics Study

Abstract

Considering the adverse effect of sulfite (SO3 2−), an effective Ni(II)- and Ru(II)-based heterometallic-supramolecular polymer (HMSMP) (polyNiRu) has been synthesized. PolyNiRu was characterized by Field-emission scanning electron microscopy (FE-SEM), and Fourier transmission infrared (FT-IR) spectroscopy. The formation of HMSMP was confirmed via UV–Vis spectroscopy. The molecular weight of polyNiRu (4.77 × 105 Da) was measured through intrinsic viscosity measurement following Mark-Houwink equation. The electrochemical behavior of polyNiRu modified glassy carbon electrode (polyNiRu_GCE) was investigated via CV and DPV. Furthermore, we have investigated the Tafel plot for this heterogeneous electrochemical system to calculate the number of transferred electrons during redox reactions. The limit of detection was found as 0.25 μM with a wide linear dynamic range of 10 to 600 μM. A probable surface mechanism has been studied toward SO3 2− oxidation at the interface of polyNiRu_GCE. Using the Butler-Volmer equation, the heterogeneous kinetic rate transfer constant and charge transfer coefficient were found as 1.02 × 10−6 cm2 s−1 and 0.68 respectively. These obtained parameters were further evaluated by simulated CV, which agreed with the experimental value. Excellent recovery with lower relative standard deviation (RSD) and high stability for 4000 s in analytic solution confirmed the reliability of using this polyNiRu_GCE in the practical assessment.