Ming-Liang Chen

Synthesis, characterization, and photocatalytic analysis of CNT/TiO2 composites derived from MWCNTs and titanium sources

Abstract CNT/TiO 2 composites were prepared using multi-walled carbon nanotubes (MWCNTs) as a starting material, and titanium(IV) isopropoxide, titanium(IV) propoxide and titanium(IV) n -butoxide as titanium sources and benzene as a solvent. The composites were characterized by N 2 adsorption, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, and UV-vis absorption spectroscopy. The photoactivity of the prepared materials was evaluated by the conversion of methylene blue (MB, C 16 H 18 N 3 S·Cl·3H 2 O) in aqueous solution under UV irradiation. It can be found that the MB removal effect of the CNT/TiO 2 composites is not only due to the adsorption of MWCNTs and the photocatalytic degradation of TiO 2 but also to electron transfer between MWCNTs and TiO 2 .

Effect of Pt treated fullerene/TiO2 on the photocatalytic degradation of MO under visible light

Platinum treated fullerene/TiO2 composites (Pt-fullerene/TiO2) were prepared using a sol–gel method. The composite obtained was characterized by FT-IR, BET surface area measurements, X-ray diffraction, energy dispersive X-ray analysis, transmission electron microscopy (TEM) and UV-vis analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. Excellent photocatalytic degradation of a MO solution was observed using the Pt-TiO2, fullerene-TiO2 and Pt-fullerene/TiO2 composites under visible light. An increase in photocatalytic activity was observed and Pt-fullerene/TiO2 has the best photocatalytic activity, which may be attributable to increase of the photo-absorption effect by the fullerene and the cooperative effect of the Pt.

SYNTHESIS OF GRAPHENE-CDSE COMPOSITE BY A SIMPLE HYDROTHERMAL METHOD AND ITS PHOTOCATALYTIC DEGRADATION OF ORGANIC DYES

Abstract A graphene-CdSe composite was synthesized by a facile hydrothermal method, and characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry. The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue (MB), methyl orange (MO) and rhodamine B (Rh.B) in aqueous solution under UV or visible light irradiation. The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution.

Photocatalytic Degradation of Methylene Blue by CNT/TiO 2 Composites Prepared from MWCNT and Titanium n-butoxide with Benzene

In this study, CNT/TiO₂ composites were prepared using surface modified Multiwall carbon nanotube (MWCNT) and titanium n-butoxide (TNB) with benzene. The composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), FT-IR spectra, and UV-vis absorption spectroscopy. The UV radiation induced photoactivity of the CNT/TiO₂ composites was tested using a fixed concentration of methylene blue (MB, C 16 H 18 N₃SㆍCl·3H2₂) in an aqueous solution. Finally, it can be considered that the MB removal effect of the CNT/TiO₂ composites is not only due to the adsorption effect of MWCNTand photocatalytic degradation of TiO₂, but also to electron transfer between MWCNT and TiO₂.

Synthesis and Characterization of Metal (Pt, Pd and Fe)-graphene Composites

In this study, we prepared graphene by using the modified Hummers-Offeman method and then introduced the metals (Pt, Pd and Fe) for dispersion on the surface of the graphene for synthesis of metal-graphene composites. The characterization of the prepared graphene and metal-graphene composites was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). According to the results, it can be observed that the prepared graphene consists of thin stacked flakes of shapes having a well-defined multilayered structure at the edge. And the metal particles are dispersed uniformly on the surface of the graphene with an average particle size of 20 ㎚.

Synthesis and Characterization of CNT / TiO 2 Photoelectrocatalytic Electrodes for Methlene Blue Degradation

In this study, two series of CNT/TiO electrodes were prepared. The decrease of surface area compared with that of the pristine carbon nanotubes (CNTs) indicated the blocking of micropores on the surface of the CNTs; was further supported by scanning electron microscopy (SEM) and field emission SEM (FE-SEM) observations. The X-ray diffraction (XRD) results showed that the CNT/TiO composites contained a mix of anatase and rutile forms of TiO particles when the precursor was TiO powder, whereas when the precursor was Ti (OC H ) (TNB), the composites contained only the typical single and clear anatase TiO particles. The energy dispersive X-ray spectroscopy (EDX) spectra showed the presence of C, O and Ti peaks for all samples. It was found that catalytic decomposition of methylene blue (MB) solution could be attributed to synthetic effects between the TiO photocatalysis and electro-assisted CNTs network, and that photoelectrocatalytic oxidation increased with an increase of CNT composition. It was also found that the photoelectrocatalytic oxidation efficiency for MB is higher than that of photocatalytic oxidation. Moreover, the CNT/TiO composites catalyst prepared by the impregnation method demonstrates higher photoelectrocatalytic activity than the mechanical mixture with the same CNT content.

Photoelectrocatalytic Properties of Ag-CNT/TiO2 Composite Electrodes for Methylene Blue Degradation

Carbon nanotubes modified with silver (Ag-CNTs) were used for the fabrication of Ag-CNT/TiO2 composite electrodes. The electrodes were characterized by X-ray diffraction, transmission and scanning electron microscopy, and energy dispersive X-ray analysis. It was found that TiO2 particles were distributed uniformly in the CNT networks, and silver particles were fixed on the surface of the CNTs.. The composite electrodes exhibited a high photoelectrocatalytic (PEC) activity. The PEC degradation efficiency for methylene blue (MB) was a synergistic effect of photo-degradation of TiO2, increased electrical conductivity by the CNT networks, an effect of the silver and a function of the applied potential. Especially, the composites treated with silver revealed an enhanced photo-degradation ability for MB and the PEC activity increased with increasing silver content.

The Improved Photocatalytic Properties of Methylene Blue for V2O3/CNT/TiO2 Composite under Visible Light

Multiwall carbon nanotube (MWCNT), vanadyl acetylacetonate (V(acac)3), and titanium n-butoxide (TNB) were used as carbon, vanadium oxide, and titanium oxide precursor to prepare V2O3/CNT/TiO2 composite. The obtained composite was characterized by BET surface area measurement, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray analysis. In addition, we used methylene blue (MB) solution under condition of visible light irradiation to determine their photocatalytic degradation efficiency. In conclusion, the V2O3/CNT/TiO2 composite had excellent photocatalytic degradation for MB solution under visible light.

Photoelectrocatalytic Degradation of Dyes in Aqueous Solution Using CNT/TiO₂ Electrode

The effect of photoelectrocatalytic (PEC) degradation for different dyes with the CNT/TiO2 electrode was studied. The prepared electrode was characterized with surface properties, structural crystallinity, elemental identification, and PEC activity. The N₂ adsorption data showed that the composites had decreased surface area compared with the pristine CNT. This indicated the blocking of micropores on the surface of CNT, which was further supported by observation via FESEM. XRD patterns of the composites showed that the CNT/TiO2 composite contained a mixing anatase and rutile phase. EDX spectra showed the presence of C, O and Ti peaks for all samples. The decomposition efifciency of the prepared electrode was evaluated by the PEC degradation of three dyes (methylene blue (MB), rhodamine B (RH.B), methyl orange (MO)). The variations of the FT-IR spectra and pH value of dye solutions were measured during the PEC system; it was found that the CNT/ TiO₂ electrode has better PEC degradation for MB solution than that of RH.B and MO. The proposed degradation mechanism was present.

Synthesis and highly visible-induced photocatalytic activity of CNT-CdSe composite for methylene blue solution

Carbon nanotube-cadmium selenide (CNT-CdSe) composite was synthesized by a facile hydrothermal method derived from multi-walled carbon nanotubes as a stating material. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectrophotometer. The as-synthesized CNT-CdSe composite efficiently catalyzed the photodegradation of methylene blue in aqueous solutions under visible-light irradiation, exhibiting higher photocatalytic activity.