Fangfang Wen

Electrocatalytic determination of nitrite based on straw cellulose/molybdenum sulfide nanocomposite.

Cellulose is the most abundant, renewable, biodegradable natural polymer resource on earth, which can be a good substrate for catalysis. In this work, straw cellulose has been oxidized through 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation, and then a TEMPO oxidized straw cellulose/molybdenum sulfide (TOSC-MoS2) composite has been synthesized via a hydrothermal method. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis confirm that TOSC and MoS2 have successfully composited. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show the TOSC as a carbon nanotube-like structure and edged MoS2 grows on the TOSC substrate. The TOSC-MoS2 modified glassy carbon electrode (GCE) is used as a simple and non-enzymatic electrochemical sensor. Cyclic Voltammetry (CV) result shows TOSC-MoS2 has excellent electrocatalytic activity for the oxidation of nitrite. The amperometric response result indicates the TOSC-MoS2 modified GCE can be used to determine nitrite concentration in wide linear ranges of 6.0-3140 and 3140-4200µM with a detection limit of 2.0µM. The proposed sensor has good anti-interference property. Real sample analysis and the electrocatalytic mechanism have also been presented.

Synthesis of S-rich flower-like Fe2O3-MoS2 for Cr(VI) removal

ABSTRACT A novel Fe2O3-MoS2 nanocomposite was synthesized directly via the solvothermal method. Scanning electron microscopy (SEM) results showed the as-prepared Fe2O3-MoS2 had a uniform 3D blooming flower-like nanostructure with a MoS2 substrate. The high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirmed the Fe2O3 nanostructures were well-dispersed on the surface of the layered MoS2. The elemental mapping results revealed Fe, O, Mo and S elements coexisted in the Fe2O3-MoS2 nanocomposite. X-ray photoelectron spectroscopy (XPS) results displayed an S-rich MoS2 structure had been formed in the Fe2O3-MoS2 nanocomposite. As expected, the S-rich Fe2O3-MoS2 nanocomposite had better photocatalytic performance on Cr(VI) reduction than that of bare Fe2O3, MoS2 and TiO2 P25.