Preparation And Characterization Of Ordered Mesoporous CMK-5 And MWNTs/metal Sulfide Composites

Ordered mesoporous CMK-5 exhibit potential applications in catalysis, capacitor and adsorption due to their large surface area, suitable pore size and highly chemical stability. CNTs, with ordered nano-array structure, exhibit good electron conductivity and excellent chemical adsorption ability. When metal sulfides were deposited onto CNTs surface, electron-hole separation and transport has been found to be significantly enhanced. This composite is attacting much attention because of their potential applications in solar cells and photocatalysis.Ordered mesoporous CMK-5 carbon materials with various pore size and surface area were synthesized using chemical vapor deposition (CVD) method by changing the CVD time and Si/Fe molar ratio. The increase of CVD time from 30 min to 90 min leaded to the increase in surface area and pore size of the carbon materials. When CVD time was prolonged beyond 120 min, it exhibited a decrease in surface area and pore size of carbon materials because the pore of CMK-5 was blocked by the deposited carbon. It has been found that the surface area and pore size of carbon materials also increased with increasing the molar ratio of Si/Fe.High-aspect-ratio of CdS nanorod has been successfully prepared by the reaction of Cd(NO₃)₂·4H₂O with NH₂CSNH₂ in ethylenediamine in the presence of acrylamide as a structure-directing agent via a solvothermal process. The morphology and size of CdS nanorod can be readily controlled by changing the amount of surfactant and the reaction time.A facile solvothermal route has been developed to coat MWNTs with CdS nanocrystal in DETA-water or EDA-water medium using Cd(Ac)2·2H2O or Cd(NO₃)₂·4H₂O as a Cd precursor and H2NCSNH2 as a sulfur source. The hybrid MWNTs/CdS nanostructure was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), FT-IR and UV-vis absorption spectroscopy. The results indicate that nano-sized CdS has been successfully in-situ encapsulated onto the surface of MWNTs.MWCNTs/Ag₂S has been successfully synthesized using AgNO₃ as a Ag precursor and Na₂S·9H₂O as a sulfur source, SDS as surfactant at room temperature. It has been shown from TEM images that diameter of composite materials increased compared to that of MWCNTs, indicating that nano-sized Ag₂S has been coated onto the surface of MWNTs.