规则中孔氧化铈的纳米铸型合成及作为高CO氧化活性金催化载体的应用

以有序的中孔炭材料CMK-3为模板,以硝酸铈为前体,利用纳米铸型法合成了具有规则结构的中孔氧化铈,考察了模板脱除温度对中孔氧化铈微结构的影响.热重、元素分析、X射线衍射、透射电镜和氮气物理吸附结果表明,炭模板的脱除温度可低至350℃,所得氧化铈具有二维六方规则结构,比表面积高达167 m~2/g,孔径分布集中在3～5nm.采用胶体沉积法将2-5nm的金溶胶粒子沉积到所得氧化铈表面制得了Au/CeO_2催化剂,考察了Au/CeO_2在CO氧化反应中的活性.结果表明,该催化剂的活性较常规氧化铈制备的金催化利有明显提高,这可能与载体的规则结构有关.

Nanocast Ordered Mesoporous CeO_2 as Support for Highly Active Gold Catalyst in CO Oxidation

Ordered mesoporous ceria oxides (CeO_2) were synthesized by nanocasting using ordered mesoporous carbon (CMK-3) as the template and cerium nitrate as the CeO_2 precursor. The as-prepared materials were characterized by thermogravimetry, elemental analysis, powder X-ray diffraction, transmission electron microscopy, and N_2 adsorption. The obtained ceria exhibits a 2-D hexagonal ordered structure with a high surface area of up to 167 m~2/g and pore size in the range of 3-5 nm. The carbon template can be completely removed at a temperature as low as 350 ℃. Such ceria was then employed as the support for the preparation of gold catalysts by the colloid deposition method. The catalytic activity of the Au/CeO_2 catalyst was evaluated in CO oxidation. An enhanced catalytic activity was observed over such a catalyst possibly due to the nano-sized particle and narrow pore size of the ordered mesoporous ceria.