Dissertation > Excellent graduate degree dissertation topics show

Solvothermal Synthesis and Photocatalytic Properties of Doped ⅡB-sulfide Nanomaterials

Author: XuZhiYou
Tutor: ZhangYongCai
School: Yangzhou University
Course: Materials Physics and Chemistry
Keywords: Nanomaterials Solvothermal Doping Znic sulfide Cadium sulfide
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 161
Quote: 0
Read: Download Dissertation

Abstract

The present thesis is aimed at exploring novel solvothermal methods to synthesize the semiconductor nanomaterials of dopedⅡB-sulfide. By doping different concentrations of metal ions (such as Mn²⁺, Cu²⁺), we can obtain ZnS:Mn, CdS:Mn, ZnS:Cu nanorods or nanopaticles with tuneable bandgaps. And the corresponding formation mechanisms of the products were also discussed. X–ray diffraction （XRD）, Transmission electron microscopy （TEM）, Energy dispersive spectroscopy （EDS）, UV–vis absorption spectrum, and Fourier transform infrared spectroscopy （FTIR） were used to characterize the as–obtained products. At the same time, we did some photodegradation experiments of MO（methyl orange） or MB（methylence blue） solution under UV irradiation with our homemade products as catalysts. The main works achieved are summed up as following:1. The controllable synthesis of hexagonal Mn-doped CdS (Cd_1-xMn_xS, x=0–0.35) nanorods from a class of solid air-stable single-source molecular precursors (cadmium manganese bis（N,N-diethyldithiocarbamate）, Cd_1-xMn_x-（DDTC）₂) has been achieved by two facile steps: first, Cd_1-xMn_x-（DDTC）₂ （x=0–0.35） was prepared directly through the precipitation reactions of stoichiometric cadmium sulfate, manganese acetate, and sodium diethyldithiocarbamate in distilled water under the ambient condition; second, pure hexagonal phase Cd_1-xMn_xS （x=0–0.35） nanorods with different aspect ratios were produced via solvothermal treatment of the precursors in ethylenediamine at 180 oC for 12 h. It was observed that the values of x played an important role in shape, size and optical characteristic of the products. The possible formation mechanism was also discussed. The homemade products were characterized by XRD, TEM, EDS, Uv-vis and FTIR. At last, we did some photodegradation experiments of MO（methyl orange） solution under UV irradiation with Cd_1-xMn_xS as catalyst. The photocatalytic experiments indicated that Cd_0.98Mn_0.02S has the best photocatalytic performance. The decolorization efficiency of 250 mL MO solution （10 mg/L） would reach 99.9% after 4.5h’photodegradation with 0.1 g of Cd0.98Mn0.02S as catalyst.2. The controllable synthesis of hexagonal Zn_1-xMn_xS （x=0–0.10） nanorods from a class of solid air-stable single-source molecular precursors (zinc manganese bis（N,N-diethyldithiocarbamate）, Zn_1-xMn_x-（DDTC）₂) has been achieved by two facile steps: first, Zn_1-xMn_x-（DDTC）₂ （x=0–0.10） was prepared directly through the precipitation reactions of stoichiometric manganese acetate, zinc acetate, and sodium diethyldithiocarbamate in distilled water under the ambient condition; second, pure hexagonal phase Zn_1-xMn_xS （x=0–0.10） nanorods with different aspect ratios were produced via solvothermal treatment of the precursors in 40 vol.% hydrate hydrazine aqueous solution at 180 oC for 12 h, It was observed that the value of x was important to shape, size and optical characteristic of the products. The possible formation mechanism was also discussed. The homemade products were characterized by XRD, TEM, EDS, Uv-vis and FTIR. Finally, we do some photodegradation experiments of MB（methylence blue） solution with Zn_1-xMn_xS as catalyst. The photocatalytic experiments indicated that the decolorization efficiency of MB solution would decrease with increasing x values in the as-syntheiszed Zn_1-xMn_xS, and ZnS nanorods have the best photocatalytic performance. The decolorization efficiency of 250 mL MB solution （10 mg/L） will arrive at 98% after 5.5 hours, photodegradation, when 0.1 g of ZnS nanorods were used as catalyt.3. The controllable synthesis of hexagonal phase Zn_1-xCu_xS （x=0–0.10） nanorods or nanoparticles （x=0–0.01） from a class of solid air-stable single-source molecular precursors (zinc copper bis（N,N- diethyldithiocarbamate）, Zn_1-xCu_x-（DDTC）₂) has been achieved by two facile steps: first, Zn_1-xCu_x-（DDTC）₂ （x=0–0.10） was prepared directly through the precipitation reactions of stoichiometric copper chloride, zinc acetate, and sodium diethyl- dithiocarbamate in distilled water under the ambient condition; second, pure hexagonal phase （x=0, 0.01） and mixed phase （x = 0.03, 0.05） Zn_1-xCu_xS nanorods were produced via solvothermal treatment of the precursors in 50 vol.% en aqueous solution at 180 oC for 12 h, while the mixed phase （x=0, 0.002, 0.005） and single hexagonal phase （x=0.01） Zn_1-xCu_xS nanoparticles were produced via hydrothermal treatment of the precursors in distilled water at 180 oC for 12 h. It was observed that the value of x affected phase, shape, size and optical characteristic of the products. The possible formation mechanism was also discussed. The homemade products were characterized by XRD, TEM, EDS, Uv-vis and FTIR. At last, we do some photodegradation experiments of MB solution with Zn_1-xCu_xS nanorods as catalyst, the experiment indicated that the decolorization efficiency of 10 mg/L MB solution will decrease with increasing of Cu²⁺, ZnS nanorods have the best photocatalytic effect, The decolorization efficiency will arrive at 94.5% after 5.5 hours, photodegradation. Whlie it will arrive at 78.4% after 5.5 hours, photodegradation with ZnS nanoparticles as catalyst.

Related Dissertations

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net Mobile