Enhanced glucose electrooxidation at a binary catalyst of manganese and nickel oxides modified glassy carbon electrode

A novel binary electrocatalyst fabricated from manganese and nickel oxides nanoparticles (MnOx and NiOx), prepared by electrodeposition, is proposed as an anode for an amplified electrochemical oxidation of glucose in NaOH solutions. Cyclic voltammetry and scanning electron microscopy images were used to characterize these electrocatalysts. It has been found that the electrocatalytic activity critically depends on the order of the deposition of the two oxides. The NiOx/MnOx/GC electrode (MnOx deposited first) showed a superior electrocatalytic activity towards glucose oxidation compared to NiOx/GC, MnOx/GC or MnOx/NiOx/GC electrodes (NiOx deposited first). The extraordinary activity obtained at the NiOx/MnOx/GC electrode is attributed to the compilation of the better adsorption of glucose molecules on the MnOx sites and the increase of conductivity of the NiOx due to the increase of Ni3+ content. The results lead us to conclude that there is a synergism between the two oxides towards the electrooxidation of glucose.

► NiOx/MnOx/GC electrode significantly catalyzes glucose oxidation. ► Order of deposition of oxides is a crucial in the electrocatalytic activity. ► A synergistic enhancement effect between the two oxides is concluded.