Fabrication Of Nanosilver Embedded Hybrid Materials By Oxidation-reduction And Sol-gel Coupling Route

Nanosilve embedded hybrid materials with manipulated morphologies and controllable size distributions have drawn considerable attention in recent decades because of their excellent stability, large specific surface area, and unique physicochemical properties and the functionalization of hybrid materials have attracted more and more interest to the use in integrated circuit, battery cathodes, antibacterial materials and catalysis. Besides, it usually used as catalyst because of its large specific heat, high hardness, large specific surface area and much active site. In this paper, we introduced the synthesis, characterization and catalytic performance of nanosilver embedded hybrid materials.The main research work is as follows:1. A facile sol-gel route to the fabrication of size-controllable nanosilver embedded hybrid materials at room-temperature is presented. The preparation process involves using three kind of organosilica precursors, i.e.tetraethoxysilane,3-mercaptopropyltrimethoxysilane and polymethylhydrosiloxane, which behaved as framework constructor, complexing agent toward metal ions and insitu reducing agent for Ag ions, respectively. The dependence of textural characteristics on the preparation parameters were investigated employing various techniques as such N2adsorption/desorption isotherms, UV-vis DRS, FT-IR and TEM measurements. It was shown that well-dispersed silver nanoparticles (AgNPs) with small particle size were successfully embedded in the hybrid skeleton, and the mean particle size of AgNPs could be controlled at ca.2-5nm. Besides, the hybrid materials exhibited high surface areas, large pore volume, tunable pore diameters.2. The effects of several key preparation parameters on the structural characteristics of samples prepared from the process described above were investigated.(1) Several samples were prepared with different MPTMS:Ag-molar ratios by changing the amount of AgNO3added to the initial gels while keeping the amounts of TEOS, PMHS, and MPTMS constant.(2) Several samples were prepared with different Ag+:MPTMS molar ratios by changing the amount of MPTMS added to the initial gels while keeping the amounts of TEOS, PMHS, and MPTMS constant.(3) Several samples were prepared with different PMHS:TEOS mass ratios while MPTMS:TEOS and MPTMS:Ag+molar ratios were kept constant, respectively. The dependence of textural characteristics on the preparation parameters were investigated employing various techniques as such N2adsorption/desorption isotherms, UV-vis DRS, FT-IR, TEM and XPS measurements. The optimized conditions are as follows:a mass ratio of PMHS:TEOS of1:10, a molar ratio of MPTMS:TEOS of1:5, and a molar ratio of MPTMS:AgNO3of1:1and putting in ammonia water after24h reacting.3. Large pore volume and high surface areas hybrid materials were obtained use different preparing conditions and were also applied for catalytic reduction of PNP. It was shown that the sample prepared as follows:mass ratio of PMHS:TEOS of1:10, a molar ratio of MPTMS:TEOS of1:5, and a molar ratio of MPTMS:AgNO3of1:4and putting in ammonia water after48h reacting showed excellent catalysis during room-temperature.Besides, when the amount of catalyst was0.15g, the reduction ability of PNP increasing clearly with increasing of reaction time and when the reaction time was60min, PNP was almost change to PAP.