环氧化物共凝胶法合成稀土氧化物掺杂碳气凝胶的研究

Compared with the simple stacking of rare-earth oxide (REO) nanoparticles, its physical and chemical properties can be efficiently enhanced by highly dispersing to the three dimension network structure of carbon aerogel. Traditional sol-gel method and ion exchange method are commonly used for preparing REO-doped carbon aerogels, which usually display three disadvantages: low amount of dopant, uneven distribution of dopant，and consumption of time and labor. Therefore, the REO-doped carbon aerogels with high dopant amount, good dispersion uniformity，and high specific surface area will be synthesized and investigated by epoxide-catalyzed co-gelation method. The RE chloride aqueous solution and epoxide will be used as catalysts to catalyze the organic RF solution and the RE chloride aqueous solution, respectively. The relationships between the preparation parameters and the physical and chemical properties of the REO-doped carbon aerogels will be established, while the structure-function relationships between the epoxide, the pH of the solution and the hydrolysis of RE ions, the nucleation and growth of the colloidal particles, the formation of the gel network will be analyzed. At the same time, intrinsic law of simultaneous gelling in two different systems will be explored, and the general synthesis method and sol-gel mechanism of the REO-doped carbon aerogels will be obtained. At last, their applications as lithium-ion battery materials will be studied. The research of REO-doped carbon aerogels derived by epoxide-catalyzed co-gelation method can provide technical reserve and theoretical basis for the research of other metal oxide doped carbon aerogels. With the support of the National Natural Science Foundation of China, lots of practical experiences have been accumulated during the research of RE oxide aerogels and carbon aerogels, which will ensure the successful completion of this project.

与稀土氧化物纳米颗粒的简单堆叠相比，将其均匀掺杂到碳气凝胶中，能有效提高其理化性能。制备稀土氧化物掺杂碳气凝胶的方法有传统溶胶-凝胶法和离子交换法，但两者都存在掺杂量低、分散不均匀和耗时耗力的问题。因此，申请人拟采用环氧化物共凝胶法，利用稀土氯化物水溶液的酸性去催化有机RF溶液凝胶，同时稀土氯化物水溶液又在环氧化物催化下凝胶，达到共凝胶，制备出掺杂量高、分散均匀性好、比表面积高的稀土氧化物掺杂碳气凝胶。建立制备技术参数与稀土氧化物掺杂碳气凝胶理化性能的对应关系，解析环氧化物和溶液PH值与稀土离子的水解、胶体颗粒的成核生长和凝胶网络的形成之间的构效关系，探索两种体系同步凝胶的内在规律，获得稀土氧化物掺杂碳气凝胶的制备方法和溶胶-凝胶机理，拓展其在锂离子电池领域的应用。申请人在国家自然科学基金（已结题）的资助下，在稀土氧化物气凝胶和碳气凝胶方面积累了丰富的实战经验，能确保本项目的顺利完成。

通过将稀土氧化物纳米颗粒均匀分散到碳气凝胶的网络结构中可获得稀土氧化物掺杂碳气凝胶。一方面能增加稀土氧化物纳米颗粒与其它反应物质的接触面积，提高其物理和化学性能；另一方面也能实现对碳气凝胶的微结构、导电性和催化性能的调控。稀土氧化物掺杂碳气凝胶的常用制备方法有：传统溶胶-凝胶法、注入法（浸渍法）和离子交换法，但都存在掺杂量低、分散不均匀和耗时耗力耗财等问题。因此，项目组成员采用环氧化物共凝胶法，以稀土元素M(=La、Y、Ce和Eu)的氯化物为研究对象，以去离子水为公共溶剂，制备出了掺杂量高、分散均匀性好、比表面积高的稀土氧化物掺杂碳气凝胶。研究了稀土氯化物的种类、反应前驱体的配比、反应温度、反应物的添加顺序、环氧化物的种类（环氧丙烷、环氧氯丙烷、环氧丙醇）和添加量、干燥方式等对稀土氧化物掺杂碳气凝胶理化性能的影响，揭示了环氧化物共凝胶法制备稀土氧化物掺杂碳气凝胶的溶胶-凝胶机理，为其它金属氧化物掺杂碳气凝胶提供了技术储备和理论支持。本项目的部分研究成果共发表论文10篇，其中9篇被SCIE收录，部分研究成果还在分析整理中。