Spherical Tin Oxide, SnO2 Particles Fabricated via Facile Hydrothermal Method for Detection of Mercury (II) Ions.

Smooth-surface spherical tin oxide particles were fabricated via hydrothermal processing route. X-ray diffraction (XRD) revealed that the particles consisted of the rutile phase of SnO2 with tetragonal structure. The spherical morphology was realized with the aid of ammonia. The aggregation of SnO2 particles could be avoided by adjusting the concentration of tin (II) chloride. Bare glassy carbon electrode (GCE) was modified with the hydrothermally prepared SnO2 particles to detect the presence of mercury (II) ions (Hg2+), in the presence of potassium chloride (KCl) as a supporting electrolyte. GCE modified with the spherical SnO2 particles that possessed small crystallite size and smooth surface exhibited significantly enhanced oxidative and reductive current of Hg2+ during cyclic voltammetry compared with its bare counterpart. The reductive current was observed to increase by two fold and the detection limit of 75 nM for Hg 2+ was achieved. This suggests that SnO2 particles are a promising chemical sensor for the detection of Hg2+ in natural waters

Preparation and characterization of tin oxide, SnO2 nanoparticles decorated graphene

SnO2 nanoparticles/graphene (SnO2/GP) nanocomposite was synthesized by a facile microwave method. The X-ray diffraction (XRD) pattern of the nanocomposite corresponded to the diffraction peak typical of graphene and the rutile phase of SnO2 with tetragonal structure. The field emission scanning electron microscope (FESEM) images revealed that the graphene sheets were dotted with SnO2 nanoparticles with an average size of 10 nm. The X-ray photoelectron spectroscopy (XPS) analysis indicated that the development of SnO2/GP resulted from the removal of the oxygenous groups on graphene oxide (GO) by Sn2+ ions. The nanocomposite modified glassy carbon electrode (GCE) showed excellent enhancement of electrochemical performance when interacting with mercury(II) ions in potassium chloride supporting electrolyte. The current was increased by more than tenfold, suggesting its potential to be used as a mercury(II) sensor

Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

A graphene-tin oxide (G-SnO2) nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). A homogeneous deposition of SnO2 nanoparticles with an average particle size of 10 nm on the graphene was observed in the FESEM and HRTEM images. The G-SnO2 nanocomposite was used to fabricate a modified electrode for the electrochemical detection of dopamine (DA) in the presence of ascorbic acid (AA). Differential pulse voltammetry (DPV) showed a limit of detection (LoD) of 1 μM (S/N = 3) in the presence of ascorbic acid (AA). Keywords: Graphene, Tin oxide, Nanocomposite, Electrochemical sensor, Biosensor, Dopamin