高比表面积纳米 MgO 的制备及其在催化反应中的应用

摘要

Nanometer magnesium oxide is widely used in various catalytic reactions because of its strong surface alkaline and stable chemical property. It was found that catalytic activity of nanometer magnesium oxide was improved with the increase of its specific surface area. The preparation methods of MgO with high specific surface area included solid phase method,liquid phase method,vapor phase method and external-template method. The methods were introduced in detail and compared,and the superiority of high specific surface area nano-MgO in catalytic reactions was also reviewed. The liquid phase method was more commonly used to prepare high specific-surface-area nano-MgO,and had the advantages of simple process,low production cost and easy industrialization. In addition,the as-prepared nano-MgO possessed uniform particle size distribution and more complete crystal structure. High-specific-area nanometer MgO had abundant pore structure and higher specific surface area,so it could provide more active sites in catalytic reactions. Meanwhile,high-specific-area MgO could also promote the molecule diffusion of reactants and products within the catalyst internal surface and increase the reaction activity. Therefore,high specific surface area nano-MgO based on the premise of keeping its strong alkaline has wider application prospect.%纳米 MgO 具有较稳定的化学性质，表面碱性较强，在催化领域应用广泛。提高纳米 MgO的比表面积，可以使其催化性能更为优良。常见的制备高比表面积纳米 MgO 的方法有固相法、液相法、气相法和外模板法。对4种方法进行详细介绍和比较，并对高比表面积纳米 MgO 在催化反应中表现出的优势进行评述。液相法工艺简便，生产成本较低，易实现工业化，是较常用的制备高比表面积纳米 MgO 的方法，且制得的样品粒度分布较均匀，晶型结构较为完整。高比表面积纳米MgO 具有较发达的孔道结构和较高的比表面积，在催化反应中可以提供更多的活性位，同时还可促进反应物和产物分子在催化剂内表面的扩散，提高反应活性，因此，在保持纳米 MgO 强碱性的前提下，高比表面积纳米 MgO 应用前景更为广阔。