Synthesis of in Situ N-, S-, and B-Doped Few-Layer Graphene by Chemical Vapor Deposition Technique and Their Superior Glucose Electrooxidation Activity

Abstract

At present, N-, S-, and B-doped grapheme-modified indium tin oxide (ITO) electrodes are produced and doping method effect on the glucose electrooxidation is investigated. Firstly, few-layer graphene is produced by chemical vapor deposition (CVD) method. Then, N, S, and B doping is carried out after graphene produced by CVD to prepare N-doped, B-doped, and S-doped few-layer graphene. N, S, and B doping is carried out by two different ways as (a) doping after synthesis of few-layer graphene and (b) in situ doping during few-layer graphene production. These materials are characterized by X-ray diffraction, scanning electron microscopy-energy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). One could note that graphene and nitrogen networks are clearly visible from SEM images. Raman spectra show that B, N, and S are doped on few-layer graphene/ITO successfully. XPS results of graphene, N-doped graphene, and in situ N-doped graphene reveal that graphene and nitrogen atoms used in the preparation of the electrodes obtain mainly in their elemental state. Then, these N-, S-, B-doped and in situ N-, S-, B-doped few-layer graphene materials are coated onto indium tin oxide (ITO) to obtain N-, S-, B-doped and in situ N-, S-, B-doped ITO electrodes for glucose (C6H12O6) electrooxidation. C6H12O6 electrooxidation measurements are investigated with cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy measurements. As a result, in situ N-doped few-layer graphene/ITO electrode displays the best C6H12O6 electrooxidation activity with 9.12 mA.cm(-2) current density compared with other N-, S-, B-doped graphene and in situ doped S and B grapheme-modified ITO electrodes. Furthermore, this current density value for in situ N-doped few-layer graphene/ITO is highly above the values reported in the literature. In situ N-doped few-layer graphene/ITO electrode is a promising electrode for C6H12O6 electrooxidation because it exhibits the best electrocatalytic activity, stability, and resistance compared with other electrodes.