摘要
用γ射线辐射法制备了铂溶胶和粒径为5nm的超细铂粉,采用机械混合法和溶胶凝胶法制备了一系列不同载体的超细铂催化剂.不同载体对提高CO氧化活性的顺序为:MgO>γAl2O3≥ZrO2>TiO2>SiO2.其中,由溶胶凝胶法制备的01%Pt/SiO2和01%Pt/TiO2的比表面积大,Pt分散度高,但活性最差.XPS结果表明,部分表面Pt0和TiO2作用生成了PtO和Ti2O3,并且Pt的分散度愈高,Pt和TiO2间的作用愈强,从而降低了CO氧化活性.而MgO负载的超细铂样品活性明显高于常规浸渍法所制样品.XPS结果表明,超细Pt/MgO表面上存在大量的化学吸附氧,这可能是MgO负载样品活性高的重要原因.
Ultrafine platinum supported on a variety of metal oxides was prepared by the γ radiation method. The support effect of the 0 1%Pt/MO x prepared by mechanical mixing of ultrafine Pt and support on the CO oxidation activity has the sequence of MgO> γ Al 2O 3 α Al 2O 3≥ZrO 2>TiO 2>SiO 2. Although the 0 1%Pt/SiO 2 and 0 1%Pt/TiO 2 prepared with ultrafine Pt by sol gel procedure possess high specific surface area and high dispersion, their activity is the lowest. It is identified by XPS measurement that some PtO and Ti 2O 3 formed from Pt and TiO 2. In contrast to the Pt/TiO 2, the ultrafine Pt/MgO sample shows obviously higher activity than that prepared by the impregnation method. A large amount of chemisorbed oxygen is found on the ultrafine Pt/MgO catalyst and this is the main reason for its high activity.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1999年第1期17-20,共4页
基金
国家自然科学基金
福特-中国研究和发展基金
关键词
铂
超细粒子
负载型
催化剂
一氧化碳
氧化
platinum, ultrafine particle, supported catalyst, support, carbon monoxide, oxidation