| Recently, environmental problems such as air and water pollution have provided the impetus for sustained fundamental and applied research in the area of environmental remediation. Among the numerous physical and chemical methods, photodegradation of organic compounds by semiconductor photocatalysts, which is an economic and ecologically safe option for solving pollution problems, has attracted intense research interest since photo-electrochemical water splitting was reported. The wide-band-gap semiconductor metal oxide (SMO), such as ZnO, which has a large direct band gap (3.37 eV), excellent chemical and thermal stability, and the electrical properties ofⅡ-Ⅵsemiconductor possessing large excitation binding energy (60 meV) at room temperature, has been widely used as photocatalysts for its high photosensitivity, environmental sustainability, and large bandgap. Synthesis, characterization of Nano-ZnO and Fe/ZnO were repororted in this paper. Some meaningful results were obtained.In this paper, the fluffy porous structure ZnO nanocrystals have been successfully synthesized using citric acid assisted sol-gel method. The ZnO nanocrystals were systematically characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), diffuse reflectance UV-vis spectroscopy. Moreover, the thermal decomposition of zinc citrate chelate compound precursor was further studied by Termogarvimety/Differential Scanning Calorimeter analyzer (TG/DSC). Finally, the ZnO nanocrystals were investigated in the photodegradation experiment, its photocatalytic activity was studied in the degradation of methylene blue (MB) dye at ambient temperature, the results indicated that the highly photocatalytic activity was exhibited using ZnO nanocrystals as photocatalyst. The fluffy porous structure ZnO architectures might be found to have potential applications in many other fields such as: chemical sensor, solar cells, optoelectronic devices, etc.Next, we report using Zn(Ac)2·2H2O, Fe(NO3)3·9H2O and NaOH as raw materials, and Fe-doped ZnO is prepared by hydrothermal method. The structural and morphology were investigated by means of X-ray diffraction and Scan election microscopy. The measurements indicate that the Fe-doped ZnO is rod. The UV diffuse reflectance absorbent properties are detected by UV-Lambda 35 spectrophotometer. The results show that the Fe-doped ZnO has strong absorption at ultral and visible region. Photodegradation of dyes in an aqueous solution is investigated using Fe-doped ZnO as a photocatalyst. The results show that Fe doped ZnO has better degradation properties than nano-ZnO material.Then, using Zn(Ac)2·2H2O, Fe(NO3)3·9H2O and NaOH as raw materials, nano- ZnO-Fe2O3 is prepared by hydrothemal method. The structural and morphology were investigated by means of XRD and SEM. The measurement indicates that the ZnO-Fe2O3 is spherical particles, and the average diameter of the particles is 30-40nm. Ultraviolet-visible (UV-Vis) spectra indicated that the nano-ZnO-Fe2O3 composite powder has strong absorption from ultraviolet light to visible light. The influence about different react temperature, time, pH and the molar ratio of Fe3+/Zn2+ is also discussed. The result indicates that the nano-ZnO-Fe2O3 composite powder has best absorption by reacting at the molar ratio of Fe3+/Zn2+ was 1:1, the temperature was 180℃, react time was 5h and pH was 7. |
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