Novel electrocatalysts for ethylene glycol oxidation based on functionalized phosphates of bimetals Mn/Ni: Morphology, crystallinity, and electrocatalytic performance

Abstract

Novel bimetallic phosphates of Mn&Ni were investigated in this study as low-cost phosphate electrodes for ethylene glycol (EG) electrooxidation at high pH (2.0 M NaOH aqueous medium). The investigated electrocatalyst was chemically prepared by two preparation methods: reflux (MnNiPh-Re) and sol-gel (MnNiPh-SG). The as-designed MnNiPh-Re and MnNiPh-SG materials were physiochemically investigated by different techniques to describe the morphology and the impact of the preparation method on its morphology besides crystallinity and chemistry. Interestingly, the preparation method significantly affects the observed morphology. In the case of the sol-gel method, the MnNiPh-SG material has nanocubes characteristics with heterogeneous orientation and exhibits micro sheets in case of reflux strategy made up of super-thin sheets having nanoscale in their thickness and connected to create a different thickness sheet. The electrocatalytic performance of MnNiPh-Re and MnNiPh-SG as working electrodes for EG oxidation was investigated in terms of anodic current density and charge transfer resistance. Interestingly, the anodic current density of the suggested phosphate electrode was increased from 0.018 mA/cm2 to 5.73 mA/cm2 because of only introducing EG to the supporting electrolyte. The fabricated MnNiPh-SG has better EG oxidation if compared with MnNiPh-Re at different EG contents from 0.0 M to 1.0 M Additionally, the improvement of the charge transfer resistances and anodic current density confirms the successful electrocatalytic oxidation of EG over the presented MnNiPh-SG.