Effect of selenium and carbon content on the electrochemical properties of molybdenum diselenide nanosheets for sensing applications

Two-dimensional (2D) nanomaterials have been extensively applied in sensing platforms due to their unique properties, including tunable electronic structures, high surface area, and excellent catalytic activity, enabling the selectice and sensitive detection of various biological compounds. However, 2D molybdenum diselenide (MoSe2) nanostructures have rarely studied in this field compared with its counterparts. In this work, we investigated the electrochemical sensing abilities of different MoSe2 nanostructures obtained via a facile hydrothermal method. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were employed to determine the structures and morphologies of the as-prepared MoSe2 samples. The analyses revealed that the MoSe2 materials were obtained in 2D nanosheet structures. The MoSe2 nanostructures were subsequently coated on glassy carbon electrodes to evaluate their electrochemical properties and performances. Voltammetric techniques were utilized to asses the electrocatalytic activities of different MoSe2-based electrodes towards three pivotal biological compounds, namely dopamine (DA), ascorbic acid (AA), and uric acid (UA). MoSe2@active carbon (AC) hybrids were also prepared to enhance the catalytic performance of the MoSe2 toward the detection of the mentioned analytes. An electrochemical sensor based on the most effective MoSe2@AC hybrid gave wide linear detection ranges of 1.25-86 mu M and 86-468 mu M for DA, 50-5128 mu M for AA, and 5-1025 mu M for UA. The sensor also indicated low detection limits of 0.16 mu M for DA, 8.22 mu M for AA, and 0.45 mu M for UA. Additionally, interference studies were conducted against common compounds present with DA, AA, and UA, demonstrating the high selectivity of the developed sensor.