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There has been a growing interest in the field of transition metal dichalcogenide (TMD) materials and their potential applications in the field of electrochemical sensors. In the present work, molybdenum diselenide (MoSe2), as a typical representative of TMD, was prepared using a facile hydrothermal method and characterized in terms of its morphological and structural properties. Then, the obtained MoSe2 was dispersed in various solvents to investigate its electrocatalytic properties towards dopamine (DA), ascorbic acid (AA), and uric acid (UA). The electrochemical measurements revealed that deionized water is an effective solvent to disperse the MoSe2 and modify electrodes with the MoSe2 for electrochemical applications. Furthermore, the glassy carbon electrode (GCE) modified with the MoSe2, referred as GCE-MoSe2, was used as an electrochemical sensor to simultaneously detect the DA, AA, and UA. The GCE-MoSe2 exhibited wide linear detection with concentration ranges of 1–333 µM for DA, 50–3440 µM for AA, and 5–1146 µM for UA in phosphate buffer solution and low detection limits (LODs) of 0.57 µM, 13.7 µM, and 1.75 µM, respectively. The electrode further displayed good selectivity, reproducibility, and stability. This work provides valuable insights on constructing electrochemical sensing devices with high analytical performance using the important two-dimensional (2D) TMD materials. [ABSTRACT FROM AUTHOR]

A novel cobalt-doped two-dimensional molybdenum diselenide/polypyrrole hybrid-based carbon nanofiber (Co/MoSe2/PPy@CNF) was prepared using the hydrothermal method followed by electrospinning technique. The structural and morphological properties of the 2D-TMD@CNF-based hybrids were characterized through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and transmission electron microscopy (TEM). The Co-MoSe2/PPy@CNF exhibited large surface area, porous structure, and improved active sites due to the synergistic effect of the components. The electrochemical and electrocatalytic characteristics of the 2D-TMD@CNF-modified electrodes were also investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The Co/MoSe2/PPy@CNF electrode was used as an electrochemical sensor for simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) and showed enhanced catalytic activity and sensitivity. Using DPV measurements, the Co/MoSe2/PPy@CNF demonstrated wide linear ranges of 30–3212 μM for AA, 1.2–536 μM for DA, and 10–1071 μM for UA with low detection limits of 6.32, 0.45, and 0.81 μM, respectively. The developed sensor with the Co/MoSe2/PPy@CNF-modified electrode was also applied to a human urine sample and gave recoveries ranging from 94.0 to 105.5% (n = 3) for AA, DA, and UA. Furthermore, the Co/MoSe2/PPy@CNF-based sensor exhibited good selectivity and reproducibility for the detection of AA, DA, and UA. [ABSTRACT FROM AUTHOR]

The development of sensitive and selective electrodes for electrochemical detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) is essential for early diagnosis and effective treatment. In this work, a nanocomposite of two-dimensional WSe2 nanosheets with carbon black (WSe2@C) was prepared by facile hydrothermal method and used to modify a glassy carbon electrode (GCE) to fabricate an electrochemical sensing platform for simultaneous determination of AA, DA and UA. The as-prepared nanocomposite was characterized in terms of structural and morphological analyses through X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical and electrocatalytic behaviors of the modified electrode (GCE-WSe2@C) were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The sensing performance of GCE-WSe2@C electrode was tested against AA, DA and UA, resulting in enhanced electrocatalytic properties compared to GCE-WSe2 and GCE-C electrodes. The GCE-WSe2@C electrode displayed wide linear ranges of 8.0 - $2456 \mu \text{M}$ for AA, 1.0 - 49.0 & 72.8 - $381.4 \mu \text{M}$ for DA and 1.0– 24.8 & 36.9– $185.2 \mu \text{M}$ for UA with low detection limits of 3.2, 0.18 and $0.42 \mu \text{M}$ , respectively. In addition, the developed electrode demonstrated high reproducibility and stability for electrochemical detection of AA, DA and UA. [ABSTRACT FROM AUTHOR]

An electrochemical-sensing platform for determination of dopamine (DA) was fabricated using MnO2–polyaniline (MnO2–PANI) composite. The MnO2–PANI composite was prepared through in situ radio-frequency plasma polymerization of aniline monomer over MnO2 under rotating conditions and followed by external iodine doping to boost conductivity of final I2–MnO2–PANI sample. The structural and morphological analyses of the composite were carried out using Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Differential pulse voltammetry was used as an effective electrochemical method for detection of dopamine. I2–MnO2–PANI composite-based sensor shows enhanced electrocatalytic activity and high selectivity towards DA in the presence of its major interferences, which are ascorbic acid and uric acid. The sensor showed a linear detection range from 12.4 to 185.2 μM with a detection limit of 2.4 μM. The sensor also exhibited long-term stability and reproducibility. Plasma process offers facile and fast production of electrode materials. [ABSTRACT FROM AUTHOR]