The Controllable Assembly Of Nanoparticles In Mesoporous Materials

Nanoparticle is intermediade between atoms and body phase. and its peculiar structure makes it different from formal materials in electrical, magnetic and catabytic properties. Nanoparticle has long been paid much attentions and the catabytic of materials has been hot once published. First of all. nanoparticle catabytic research requires us could produce single scattered and stability of nanoparticle. Which is to be settled in catabytic field. Silver has been widely used in catabytic reaction system, as high selectivity catalyst. Comparing with other nanoparticles. silver nanoparticle is more difficult to control, more easily gather and less stable. Making single scattered and various of particle size silver nano materials is much more difficult. The work is focus on looking for one moderate mesaporous material as carrier, and choosing one method to make silver particle into porelikes of mesaporous. making use of mesaporous material's limit effect to obtain particle size, single scattered and stabitity of silver nanoparticle.The details are as follows:(1) Firstly, we succeed in synthesizing mesoporous materials SBA-15. with six direction porous. Through BET characterization ways SBA-15. Specific surface area is 634.9 m2/g, aperture is 6.8 nm. Using nitric acid remove the surfactant of mesoporous material. Its best process condition is:density of nitric acid is 6 M. the temperature of backflow oxidized is 60℃. back flowing for-4 hours. Then making use of the SBA-15 as object of silver nanoparticle. Silver ions are led into proelikes of mesoporous materials, by immersion method. Making full use of its inner active groups. with the reduction method to make silver nanoparticle in-situ-assembly into SBA-15's porelike. Through various characterization ways, which turn out that the silver nanoparticle in porelike are single scattered and uniform partric size about 6nm. The loading capacity of silver nanoparticle is 3.2 percent.(2) Successfully making out mesoporous material FDU-5 with Ia3d structure, in which we get high dispersion siiver nanoparticles. Many characterization ways show that silver nano particles are evenly disdributed in porelikes of mesoporous materious FDU-15. EDS research indicates that silver's besr cindoruk is about 8.3wt%. At last, we also observe and study the FDU-15 catalyst whose catalytic properties in methne catalyse. As its difficult to keep higher activity and stability. so its catalytic effect is not idead.(3) When choose SBA-15 as template and sucrose as carbon source pioneer content. we make out the mesoporous carbon materials of CMK-3 and the XRD suggested that, it hold the ordered porelike of SBA-15, and the aperture is 3.8nm. At the same time, there come into being a new method which make silver particle at pore of CMK-3, and the silver particles form high dispersion in mesoporous carbon materials through the inside the aperture is between 2-4nm. Compared with the tratidional immersion method. the load silver particle that making by the new method has highly of dispersion and uniformity. it has better thermal stability and there was no big particles were found. At the end of the experiment, we compared the two kinds of load type catalyst performance and the results suggested that. catalyst of mesoporous carbon materials which load silver that making by insitu method has advantage of that by immersion.