用超临界流体沉积法以无机盐为前驱物制备纳米复合材料.超临界二氧化碳为溶剂，乙醇或乙二醇为共溶剂，AgNO3为前驱物，SBA-15为载体，在50℃、23~25MPa、3~24h条件下制备担载型纳米复合材料.反应结束后，经焙烧、还原处理，可得到Ag/SBA-15纳米复合材料.经XRD、TEM表征发现，担载的Ag纳米粒子分散均匀，粒径范围3~7nm；纳米线宽度5~9nm，长度由十几纳米到几微米，分散性较好.实验研究表明，超临界流体沉积法是制备纳米复合材料的有效方法，选择合适的共溶剂可以用超临界二氧化碳溶解无机盐.选择合适的沉积条件可以控制复合材料中金属相的形态.
对制备的复合材料进行催化活性评价表明，300℃下CO选择氧化反应可以完全转化.
Ag/SBA-15 nanocomposite was prepared by supercritical fluid deposition (SCFD) method, with AgNO3 as the precursor and ethanol or glycol as the cosolvent. AgNO3 was firstly deposited onto the SBA-15 support at 50℃, 23-25MPa, and reacted for 3-24h. The resultant composite was then subjected to calcination and reduction treatment for obtaining Ag/SBA-15 nanocomposite. Characterizations with XRD and TEM show that Ag nanoparticles (with sizes of 3-7nm) or nanowires (5-9nm in width and tens of nanometers to several micrometers in length) are formed in the nanochannels of SBA-15 support. It is demonstrated that SCFD is a green and effective method for preparation of nanocomposite. With the aid of cosolvent, the supercritical carbon dioxide can dissolve the inorganic metallic salts. Moreover, the morphologies of the nanocomposite can be controlled to some extent by selecting the deposition conditions. A catalytic test on the Ag/SBA-15 nanocomposite shows that the sample has a moderate activity, with the complete conversion of CO at 300℃.
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