ZnO多壳层纳米空心微球的合成与气敏性质研究

发布时间：2018-04-19 18:11

本文选题：碳微球 + ZnO　；参考：《青岛科技大学》2015年硕士论文

【摘要】：氧化锌(ZnO)是一种重要的功能材料,在催化、化妆品、医药、太阳能等领域有着广泛的应用。作为最早使用的半导体气敏材料之一,ZnO具有制备简单、价格便宜、无毒性、稳定性好等优点,近年来,人们制备了多种形貌的ZnO材料,如ZnO纳米线、ZnO纳米棒、ZnO纳米颗粒以及花状、管状等形貌,ZnO的不同形貌表现出不同的气敏性能和选择性,但最终目标是要找到一种稳定性好,选择性好,工作温度低,灵敏度高的材料。本论文以碳微球作为牺牲模版,采用吸附-煅烧的方法,通过多种调控措施,合成了ZnO实心球和ZnO多壳层空心结构的纳米微球,并对其进行了大量的表征。以无水乙醇和甲醛作为目标气体,采用静态配气法研究了不同壳层的ZnO空心微球的气敏性能,对气敏性能最好的三壳层ZnO空心微球进行了Sn元素的掺杂和Ag单质的负载,得到了掺杂Sn和负载Ag的三壳层ZnO空心微球,并对其气敏性能进行了测试和研究。本论文的主要研究内容如下：首先以蔗糖为原料在水热体系中合成了不同尺寸的碳微球,以此作为牺牲模版合成了不同壳层的ZnO空心纳米微球。对碳微球进行了红外光谱(IR)、扫描电子显微镜(SEM)和热重分析(TG)的表征。Zeta电位表征显示碳微球表面带有负电荷,红外表征显示碳微球表面含有大量-OH和.COOH,扫描电子显微镜表征显示碳微球表面有大量的微孔,这些特征都有利于碳微球对金属氧离子的吸附。其次用水热吸附—煅烧的方法,通过调节前驱体浓度、吸附温度、吸附时间、溶剂组成、升温速率、煅烧程序等一系列方法合成了ZnO实心球、ZnO单壳层、ZnO双壳层和ZnO三壳层空心纳米微球,并对这四种纳米材料进行了SEM、TEM、X射线粉末衍射(XRD)、能量色散X射线光谱(EDX)、TG和氮气吸附比表面测试(BET)等表征。对以上材料进行了乙醇和甲醛气体的气敏性能测试研究。气敏测试结果显示ZnO三壳层纳米空心微球的气敏性能远远高于ZnO实心球、ZnO单壳层空心微球和ZnO双壳层空心微球。选取气敏性能最好的ZnO三壳层空心纳米微球,通过共吸附的方法进行了Sn元素的掺杂,又通过硼氢化钠还原法进行Ag单质的负载,合成了基于ZnO三壳层纳米空心微球的SnO2-ZnO、Ag/ZnO、SnO2-Ag/ZnO三壳层纳米空心微球,对其进行了EDX等表征,并对这三种ZnO纳米空心微球材料进行了乙醇气体的气敏性能测试和研究。结果显示Sn元素掺杂对ZnO空心纳米材料的灵敏度有少量提高,而Ag单质的负载对其气敏性能提升较大。最后对上述经过掺杂或负载的ZnO空心微球材料进行了其他气体的气敏性能测试,例如丙酮,甲醇,甲醛,氨水,三氯甲烷等。
[Abstract]:Zinc oxide (ZnO) is an important functional material, which is widely used in catalysis, cosmetics, medicine, solar energy and so on.As one of the earliest semiconductor gas sensing materials, ZnO has many advantages, such as simple preparation, low price, non-toxicity, good stability and so on. In recent years, many morphologies of ZnO materials have been prepared.For example, ZnO nanowires, ZnO nanorods, flower-like, tubular and other morphologies show different gas-sensing properties and selectivity, but the ultimate goal is to find a kind of good stability, good selectivity and low working temperature.A material of high sensitivityIn this paper, carbon microspheres were used as sacrificial templates. By means of adsorption-calcination method, ZnO solid spheres and ZnO multi-shell hollow nanospheres were synthesized and characterized.Using anhydrous ethanol and formaldehyde as the target gas, the gas-sensing properties of ZnO hollow microspheres with different shell layers were studied by static gas distribution method. Sn doping and Ag loading were carried out on the three-shell ZnO hollow microspheres with the best gas sensitivity.Three-shell ZnO hollow microspheres doped with Sn and Ag were obtained and their gas-sensing properties were tested and studied.The main contents of this thesis are as follows: firstly, carbon microspheres of different sizes were synthesized in hydrothermal system using sucrose as raw material, and then ZnO hollow microspheres with different shell layers were synthesized as sacrificial templates.The characterization of carbon microspheres by IR, SEM (SEM) and TGA (thermogravimetric analysis) showed that the surface of carbon microspheres was negatively charged.Infrared analysis showed that there were a lot of -OH and .COOH on the surface of carbon microspheres, and scanning electron microscopy showed that there were a lot of micropores on the surface of carbon microspheres, which were favorable to the adsorption of metal oxygen ions on carbon microspheres.Secondly, by adjusting the concentration of precursor, adsorption temperature, adsorption time, solvent composition and heating rate,A series of methods, such as calcination procedure, have been used to synthesize ZnO solid spheres, single shell ZnO double shell and ZnO three-shell hollow nanospheres.The four nanomaterials were characterized by SEMMOTEMN X-ray powder diffraction (XRDX), energy dispersive X-ray spectroscopy (EDX) TG and nitrogen adsorption specific surface test (BET).The gas sensing properties of ethanol and formaldehyde were studied.The gas sensing results show that the gas sensing properties of ZnO trishell hollow microspheres are much higher than that of ZnO solid spheres and ZnO double shell hollow microspheres.The hollow ZnO hollow microspheres with the best gas-sensing properties were selected, and Sn was doped by co-adsorption method, and Ag was loaded by sodium borohydride reduction method.Sno _ 2-ZnO _ (2) O _ (2) O _ (2) O _ (2) O _ (2) O _ (2) O _ (2) O _ (2) nanospheres were synthesized and characterized by EDX. The gas sensing properties of these three kinds of ZnO hollow microspheres were tested and studied by ethanol gas.The results show that the sensitivity of Sn doping to ZnO hollow nanomaterials is slightly improved, while the gas sensing properties of Ag loaded on hollow nanomaterials are greatly improved.Finally, the gas-sensing properties of the doped or loaded ZnO hollow microspheres were tested for other gases, such as acetone, methanol, formaldehyde, ammonia water, chloroform and so on.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.41;TB383.1

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