Effect of Carbon Layer Thickness on the Electrocatalytic Oxidation of Glucose in a Ni/BDD Composite Electrode

Abstract

High-performance non-enzymatic glucose sensor composite electrodes were prepared by loading Ni onto a boron-doped diamond (BDD) film surface through a thermal catalytic etching method. A carbon precipitate with a desired thickness could be formed on the Ni/BDD composite electrode surface by tuning the processing conditions. A systematic study regarding the influence of the precipitated carbon layer thickness on the electrocatalytic oxidation of glucose was conducted. While an oxygen plasma was used to etch the precipitated carbon, Ni/BDD-based composite electrodes with the precipitated carbon layers of different thicknesses could be obtained by controlling the oxygen plasma power. These Ni/BDD electrodes were characterized by SEM microscopies, Raman and XPS spectroscopies, and electrochemical tests. The results showed that the carbon layer thickness exerted a significant impact on the resulting electrocatalytic performance. The electrode etched under 200 W power exhibited the best performance, followed by the untreated electrode and the electrode etched under 400 W power with the worst performance. Specifically, the electrode etched under 200 W was demonstrated to possess the highest sensitivity of 1443.75 μA cm−2 mM−1 and the lowest detection limit of 0.5 μM.

Understanding the active sites and associated reaction pathways of metal-free carbocatalysts in persulfate activation and pollutant degradation

“…The increasing environmental pollution with the fast development of various industries calls for efficient and low-cost methods to remove the toxic and refractory pollutants from water radically. 1–4 The current methods involve adsorption, 5–7 Fenton oxidation, 8,9 Fenton-like oxidation, 10,11 electro-Fenton, 12,13 photo-Fenton, 14,15 electrochemical oxidation, 16,17 photocatalysis 18–21 and others. 22–26 Among these methods, Fenton-like oxidation based on peroxomonosulfate (PMS) and peroxydisulfate (PDS) has attracted significant attention due to its long life spans, strong oxidation ability, ease of storing and transporting PMS/PDS relative to liquid H 2 O 2 , applicability to a diversity of refractory organic pollutants, and capability to withstand a wide pH range, which is superior to the Fenton process requiring H 2 O 2 as the reactant, thus causing the storage and delivery to be difficult.…”