【作者】 沈宗华；

【导师】 王安杰；

【作者基本信息】 大连理工大学 ， 工业催化， 2006， 硕士

【摘要】 硫化锌材料具有许多特殊的光电性能,在薄膜电致发光装置、光电二极管、红外窗材料以及光催化剂等领域有着广泛的应用。纳米尺寸的ZnS因其能带宽度大于其相应的体相材料,而具有更广泛的应用前景。但其应用受制于其稳定性,因为纳米材料高的化学反应活性使其易于氧化、聚集,进而导致结构和性质的巨大变化,因此提高ZnS材料的稳定性十分必要。要达到这个目的可采用的方法即是将纳米材料组装到有固定孔道的模板中,或在其外表面镀一层惰性的薄膜。近年来,MCM-41因其规则的六方结构和均一孔径而成为一种广泛研究的组装载体。 本文利用溶剂热法、微波法和等体积浸渍法三种方法在介孔MCM-41中组装ZnS纳米晶体,提高纳米ZnS材料的稳定性。并用X射线衍射（XRD）,紫外可见光谱（UV-Vis）,N₂吸附（N₂ adsorption-desorption isotherms）,透射电镜（TEM）等手段对得到的材料进行表征。由XRD计算得到三种方法制得的ZnS粒子尺寸在1.6～2.0nm间。ZnS的存在使MCM-41骨架强度降低,并导致比表面积、孔径和孔体积的减小。量子尺寸效应引起UV-Vis光谱蓝移28～45nm。表征结果表明由溶剂热合成的纳米ZnS材料主要集中在孔内,尺寸较小且载体MCM-41骨架结构保持完整,证明溶剂热法是一种有效的组装方法。最后对溶剂热法考察实验条件发现本文所提出的溶剂热合成法,可以在较宽的合成条件下获得ZnS/MCM-41材料,并得到了最佳实验条件: （1）硫化过程:H₂S流速80ml/min;硫化温度120℃;硫化时间2h;固定床硫化。 （2）制备ZnO/MCM-41过程的最佳实验条件:反应物浓度为0.03M;晶化温度为70℃;晶化时间为2h;无水乙醇为溶剂;选乙酸锌为锌源。更多还原

【Abstract】 As a wide-band gap semiconductor, ZnS particles have been found applications in thin-film electroluminescent devices, light-emitting diode, IR windows materials and photocatalysis. Nanosized materials are of importance due to its novel properties which differ from its bulk. It is well accepted that the stability of nanoscale materials is a key factor which determines their applications. Nanoscale materials often exhibit high chemical reactivity. The high chemical reactivity often results in dramatic changes in their structures and properties, which limits their applications. In order to lower the chemical reactivity of ZnS, some researchers prepared the nanomaterials in porous materials or the other inert film. With the protection of porous materials or the inert film, the nanocrystals were not easy to aggregation. In recent years, many studies indicate that the mesoporous MCM-41 is one of the best host materials, due to its regular hexagonal arrays of uniform pore opening.In order to enhance the stability of the nano-sized materials, the present work describes the preparation of binary semiconductor ZnS nanocrystals in the channels of mesoporous MCM-41 using solvothermal method, microwave method and pore value impregnation. The nano-sized materials prepared by the three methods were characterized by XRD, UV-Vis, N₂ adsorption-desorption isotherms and TEM et al. It is shown that the nano zinc sulfide crystals are about 1.6-2.0 nm. The existence of ZnS inside the host results in the decrease of surface area, pore diameter and pore volume. And a blue shift（28⁴5nm） in UV-Vis absorption spectra is observed. It shows that the solvothermal method is an effective route to assemble zinc sulfide into the mesoporous channels of MCM-41. The diameter of zinc sulfide synthesized by solvothermal method is smaller and the hexagonal order of the host material is maintained during the assembly process. In addition, the synthesis conditions of the solvothermal method are investigated. The results show that the ZnS/MCM-41 materials assembled by solvothermal method can be achieved in a wide range of conditions. And the best conditions are as follows:（1） Sulfidation conditions: H2S flow rate 80 ml/min, temperature 120℃, time 2h.（2） The conditions of synthesizing ZnO/MCM-41: Zn（CH₃COO）₂ concentration 0.03M, crystalization temperature 70℃, crytalization time 2 h, ethanol as the solvent.更多还原