Synthesis and characterization of 2D metal carbide (MXene) and its composites with ZnS nanoparticles for electrochemical sensing of dopamine

Abstract

21st century definitely being an era of nanotechnology, has discovered a new world in material science, the advancement in which has extended to two-dimensional nanomaterials. Among the two dimensional nanomaterials, graphene and its derivatives have ruled over for quite some time, the next big thing in this field is the two dimensional metal carbides and nitrides, popularly known as MXenes. MXene being a new born in this field is not so much explored yet, still it has been successful enough to draw attention towards itself on the basis of its revolutionary properties and commercial applications. Niobium carbide (Nb2C) is one of the most important member of MXene family, which great importance in energy storage devices (LIBs and supercapacitors). This research work comprises of etching of Nb2C from parent MAX phase (Nb2AlC) at different temperatures i.e. 55˚C, 65˚C, 75˚C and 85˚C. The as-synthesized Nb2C was then doped with Lanthanum by using two approaches i.e. co-precipitation and hydrothermal method. The morphological, elemental, and optical analysis of these prepared samples was done with the help of XRD, SEM, TEM, EDS, FTIR, and UV-Vis spectroscopy. The application of Nb2C in electrochemical sensing of dopamine (neurotransmitter) was checked by the help of differential pulse voltammetry (DPV). To enhance the electrochemical properties of Nb2C, it was fabricated with zinc sulphide quantum dots (synthesized hydrothermally). The formation of quantum dots and nanocomposites was also confirmed by their FTIR, XRD, SEM, EDS, UV-Vis and PL spectra. The hence produced MXene-QD nanocomposite proved to be a very effective electrode material to detect dopamine electrochemically with a wide linear detection range of 0.09-0.82 mM, a very low detection limit of 1.39 μM and excellent sensitivity of 12.1 μAμM-1. The modified glassy carbon electrode also proved to be exceptionally selective towards dopamine in the presence of interfering agents like ascorbic acid, citric acid and glucose.