Ni纳米线/SiO2复合气凝胶的制备及机理分析

摘要

The Ni nanowires/SiO2 aerogels catalysts were prepared by sol-gel process combined with supercritical drying using TEOS, nickel nitrate and ethylene glycol as raw material.The samples were characterized by means of AAS, BET, TEM and XRD etc.The results indicate that the Ni content of Ni/SiO2 can be as high as 15％ (mass fraction), the apparent density is 0.22 g/cm3, the specific surface area is 494.4 m2/g, pore volume is 1.80 cm3/g and the average pore size is 14.6 nm.This Ni nanowires (10-60 nm in length) and unreduced nickel species are highly dispersed in the porous SiO2 matrix.After calcined at 600 ℃ for 3 h in Ar atmosphere, the crystal structure of Ni nanowires becomes more optimal but no obvious aggregation occurs, which indicates good thermal stability of the composite aerogel.%以正硅酸乙酯和硝酸镍以及乙二醇为原料,采用溶胶-凝胶法和超临界干燥工艺制备负载金属Ni纳米线的SiO2复合气凝胶.采用AAS,BET,TEM及XRD等测试手段对样品进行表征.研究结果表明:Ni/SiO2气凝胶负载的Ni含量(质量分数)约为15%,其表观密度为0.22 g/cm3,比表面积为494.4 m2/g,孔容为1.80 cm3/g,平均孔径为14.6nm;负载的Ni以非晶态的单质Ni纳米线(长度为10～60nm)和-Ni-O-Si-键组成的化合物形态均匀地分布在SiO2气凝胶三维网络骨架结构上;经Ar中600℃和3 h热处理后,Ni纳米线由非晶态转变为晶态,纳米线略有长大,但未出现团聚现象,显示出较强的热稳定性.