【作者】 翟晶；

【导师】 陈建峰；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2011， 博士

【摘要】 纳米催化剂由于其高效的还原或氧化作用,在催化或光催化领域的应用非常广泛,与普通商用催化剂相比,表现出高活性和高选择性等优异的催化性能。在反应中,纳米催化剂的尺寸、形貌、表面性质等对其活性和选择性起到了关键的作用。纳米催化剂制备过程中的条件,如原料浓度、反应时间、反应温度、溶剂比例和表面活性剂等,对于控制制备纳米催化剂至关重要。目前,人们对各种纳米催化剂的制备和应用做了大量研究,取得了丰硕的成果,同时也提出了纳米催化剂在实际应用中出现的许多问题。本论文立足于绿色、廉价、简易、可工业化放大的制备方法,来获得尺寸、形貌及表面性质可控的纳米氧化锌光催化剂、纳米铜催化剂,并且发挥优化设计理念,对纳米氧化锌光催化剂、纳米铜催化剂进行了有针对性的表面改性。本论文从控制制备、表面改性及提高产品应用性能等方面开展了研究工作,全文的主要内容和创新点如下：1、系统研究了水热法控制制备多形貌、多尺寸纳米氧化锌的制备工艺。考察了原料浓度、水热温度、水热时间、pH值、溶剂比例等因素对氧化锌颗粒尺寸和形貌的影响,结果表明：通过不同原料的水热反应,可以得到类球状、棒状、花状的纳米氧化锌光催化剂,调节原料浓度、水热温度、水热时间、pH值及溶剂比例等参数,可以控制光催化剂的形貌和尺寸。该制备方法原料简单价廉,调控手段简单,适于工业化放大生产。2、以罗丹明B等为降解对象,研究了水溶液中各种产品的光催化活性,考察了产品形貌、粒径、表面处理和使用条件对光催化性能的影响,选取了利于提高光催化效率的途径。实验结果表明：本论文所报道的方法所制备的纳米氧化锌光催化剂均具有良好的光催化性能,减小颗粒粒径、增大比表面积、较低温度煅烧有利于得到高催化性能的光催化剂,选取适当用量、调节体系pH值等,可以促进光催化体系的迅速降解。3、创新性的设计、制备并表征了核壳结构的纳米ZnO@SiO2、ZnO@@SiO2光催化剂颗粒,对其光催化性能进行了测试,验证了其在光催化应用中的优势和设计思路的正确性。4、系统研究了液相还原法制备纳米铜催化剂的制备工艺。考察了原料浓度、体系温度、反应时间、溶剂比例和表面活性剂等对铜催化剂颗粒的影响,结果表明：该工艺可以得到形貌可控、粒度可调、分散均匀、质量稳定的纳米铜催化剂,为工业化放大生产提供了基础。5、创新性的设计、制备并表征了核壳结构的纳米Cu@C催化剂颗粒,对其催化性能进行了测试,验证了其在苯羟基化催化反应中的优势和设计思路的正确性。6、在两种催化剂基础相材料的制备实验基础上,结合液相还原法与高通量反应器的特点,利用超重力旋转床和套管式微反应器对制备过程进行了连续式放大研究,对烧杯实验的放大制备优化了产品形貌、尺寸、分散性能,充分证明了高通量反应器在微观混合和反应传质方面的优势。更多还原

【Abstract】 Nano-catalyst, which showed highly efficient the reduction or oxidation properties, was widely used in the catalysis or photocatalysis areas. Compared to the commercial catalyst, nano-catalyst possessed higher activity, selectivity, and more excellent catalytic performance. The partical size, mophology and surface properties of the nano-catalyst played the key role of the activity and selectivity. The properties of the nano-catalyst were affected by the preparation conditions, such as regant concentration, duration time, temperature, solvent ratio, surfactant, etc. Recently, lots of reasearch work on the preparation and application of nano-catalyst has been reported. However, the applications of nano-catalyst are still a challenge to the scientists.Herein we report on the synthesis of nano-ZnO and Cu catalysts with controllable particle size, morphology and surface properites through a simple green, cheap and easy for industrial way. The surface modifications to the nano-ZnO and Cu catalysts were researched separatly in order to design an optimized catalyst structure.The main content and innovations are summarized as follows. 1、Nano-ZnO with different morphologies and particle sizes can be successfully synthesized using a simple hydrothermal method. The effects of the reagent concentration, hydrothermal temperaure, duration time, slurry pH value and solvents ratio to the nano-ZnO morphologies and particle sizes were studied. Sphere-like, rod-like and flower-like nano-ZnO catalysts were obtained by changing the different hydrothermal reagents. The morphologies and particle sizes of the photocatalysts could be contralable synthesized by adjusting the reagents concentration, hydrothermal temperaure, duration time, slurry pH value and solvents ratio. This simple preparation method with the inexpensive raw materials is easy to control which could be potential enlarged in industry.2、The photocatalytic activities of differenct samples in the water solution were researched using Rhodamine B as the degradation target. The effects of products morphology, partical size, surface modification and system conditions to the photocatalytic properties were also studied. The optimized method for increase the photocatalytic efficiency was found. The results showed that as-prepared nano-ZnO catalysts all posessed good photocatalytic properties. Decreasing of particle size, increasing of specific surface area and low temperatur calcining will lead to the increase of the photocatalytic properties. The degradation speed of the whole photocatalytic system will be increaed by adjusting the concentration of the catalysts and the pH value of the slurry. 3、Novel nano core/shell strctured ZnO@SiO2 and ZnO@@SiO2 photocatalytic particles were successfully designed and synthesized. The photocatalytic propereties were researched. The results showed that the core/shell strctured ZnO@SiO2 and ZnO@@SiO2 photocatalytic particles have potential application in catalysts area, which proved the advantage in the photocatalytic application area and the correctness of our design.4、Nano Cu catalysts can be successfully synthesized using liquid phase reduction method. The effects of the reagents concentration, system temperature, duration time, solvents ratio and surfactants to the Cu particles were studied in our research work. The well-dispersed nano Cu catalyst particles with contralable mophology and particle size can be obtained by the simple method, which could be potential, applied in industry area.5、A novel nano core/shell strctured Cu@C photocatalytic particles were successfully designed and synthesized. The photocatalytic propereties were reseached. The results showed that the core/shell strctured Cu@C photocatalytic particles have potential application in catalysts area, which proved the advatage in the Benzene hydroxylation catalytic application area and the correctness of our design.6、Based on the lab-preparations of the two kinds of catalysts, the whole synthesis systems were enlarged throughout tube-in-tube microreactor and the rotating packed bed combining with liquid phase reduction method. The tube-in-tube microreactor and the rotating packed bed can significantly improve the dispersity of the particles.更多还原