本文選題：微米級ZnO　切入點：ZnO/CuO復合粉體　出處：《華中科技大學》2015年碩士論文　論文類型：學位論文

【摘要】：隨著人類文明的高速發(fā)展與進步,由此帶來了一系列的資源短缺、環(huán)境污染問題,特別是水資源的污染問題已經(jīng)引起人們的廣泛關注。其中研究的熱點之一是采用ZnO和TiO2等半導體氧化物材料作為光催化劑催化處理污水中有機污染物。ZnO屬于直接寬禁帶半導體材料(Eg=3.37eV),其熱力學穩(wěn)定晶體結構為纖鋅礦結構。ZnO具有化學性質穩(wěn)定、安全廉價、易合成及較高的光催化效率等特點,是一種光催化領域中應用較廣泛的新型半導體材料。但是ZnO的催化效率存在著一些不足,一方面其只對太陽光中的紫外區(qū)域有很好的吸收,不能有效吸收可見光部分;另一方面,ZnO電子-空穴對容易復合,降低了光催化性能。所以,一些基于ZnO的復合光催化材料被相繼研究,這些材料擁有更寬的光響應范圍和更高的光催化降解活性。本文以ZnO為研究主體,對微米級ZnO及ZnO/CuO復合粉體的結構,形貌,性能進行了一系列研究。具體如下:(1)以硝酸鋅為原料,通過超聲噴霧熱解法制備球形ZnO粉體。對前驅體進行TG-DSC測試,分析了硝酸鋅熱分解得到ZnO的過程。實驗結果表明:通過改變電阻爐溫度及前驅體溶液濃度,能夠有效控制產(chǎn)物粒子的粒徑與形貌。較高的反應溫度,有助于合成出表面更加光潔,球形度更好的ZnO粉體,但溫度不宜過高;提高硝酸鋅溶液濃度所制得產(chǎn)物的粒徑較大,球形度也會變差;并且在前驅體溶液中添加不同的添加劑也會對樣品的形貌產(chǎn)生明顯的影響。(2)以硝酸鋅、硝酸銅的混合水溶液作為前驅體溶液,通過改變兩者的復合比例,在爐子溫度恒定為700℃下采用噴霧熱解技術成功制備了ZnO/CuO復合中空球形顆粒。利用X射線衍射儀、掃描電子顯微鏡、能譜儀、紫外可見分光光度計對所合成的復合材料的結構、形貌及UV-Vis吸收性能進行了表征,并對復合樣品光催化降解甲基橙(MO)進行了考察。實驗結果證明:ZnO/CuO復合材料在整個紫外與可見光區(qū)都有良好的吸收,顯著增大了光譜的吸收范圍。其光催化性能明顯比純ZnO更高,其中又以復合5%CuO的復合樣品的催化效率最高。
[Abstract]:With the rapid development and progress of human civilization, this has brought about a series of resource shortages and environmental pollution problems. In particular, the pollution of water resources has attracted widespread attention. One of the research hotspots is that the use of semiconductor oxide materials such as ZnO and TiO2 as photocatalysts for the treatment of organic pollutants in wastewater. The thermodynamically stable crystal structure of Wurtzite structure. ZnO has stable chemical properties. It is a new semiconductor material widely used in the field of photocatalysis, such as safe and cheap, easy to synthesize and high photocatalytic efficiency. However, there are some shortcomings in the catalytic efficiency of ZnO. On the one hand, it only absorbs the ultraviolet region of sunlight, and it can't absorb visible light effectively. On the other hand, ZnO electron-hole pair is easy to compound, which reduces the photocatalytic performance. Some composite photocatalytic materials based on ZnO have been studied one after another, and these materials have wider photoresponse range and higher photocatalytic degradation activity. In this paper, the structure and morphology of micron ZnO and ZnO/CuO composite powders are studied with ZnO as the main body. A series of studies were carried out on the properties of spherical ZnO powders prepared by ultrasonic spray pyrolysis with zinc nitrate as raw material. The precursor was tested by TG-DSC. The process of obtaining ZnO by thermal decomposition of zinc nitrate was analyzed. The experimental results show that the particle size and morphology of the product can be effectively controlled by changing the temperature of the resistor furnace and the concentration of the precursor solution. It is helpful to synthesize ZnO powder with more smooth surface and better sphericity, but the temperature should not be too high, the particle size of the product prepared by increasing the concentration of zinc nitrate solution is larger, and the sphericity will also become worse. In addition, adding different additives to the precursor solution also had a significant effect on the morphology of the sample. (2) the mixed aqueous solution of zinc nitrate and copper nitrate was used as the precursor solution, and by changing the composite ratio of the two solutions, ZnO/CuO composite hollow spherical particles were successfully prepared by spray pyrolysis at a constant furnace temperature of 700 鈩，

本文編號：1557021