Honggui Wang

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 novel yttrium-doped graphene oxide nanocomposite for dye removal

A novel yttrium-doped graphene oxide (GOY) composite was prepared by a hydrothermal method. The morphology results showed that graphene oxide (GO) can successfully form a composite with yttrium and that the as-prepared GOY had a nanoflake structure. From the photoelectrochemical analysis and photoluminescence (PL) spectra, the primary role of GO in Y2O3 was confirmed as an electron conductor, which enhanced the photocurrent density. As expected, the as-obtained GOY composites had better photocatalytic performance for the decomposition of methylene blue molecules than bare GO and Y2O3. The 5 GOY (10 mg) could degrade MB (25 ppm) thoroughly (∼100%) within 10 min, which was quite comparable with the commercial TiO2 P25 under UV irradiation. In addition, a possible mechanism of photocatalysis is 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.