摘要
借助于ＣＡ，ＩＣＰ－ＡＥＳ和ＸＰＳ测定了在常压综合法氨氧化装置中使用的Ｐｔ－Ｐｄ－Ｒｈ合金系催化网的组成与表面状态的变化。随着催化网使用时间延长，Ｐｔ的体积浓度降低，Ｆｅ和Ｃａ污染增大。催化网表层中主组元的化学状态为Ｐｔ°，Ｐｄ°，Ｒｈ°，ＲｈＯ２和Ｒｈ２Ｏ３。催化网表面Ｐｔ明显贫化，而Ｐｄ和Ｒｈ相对富集。在合金中增高Ｐｄ的浓度，可降低Ｐｔ的损耗，降低表面Ｒｈ２Ｏ３浓度，因而有利于提高氨转换率。
Changes of composition and surface state of catalyst gauztes made of Pt-Pd-Rh alloy systems were determined by the chemicalanalysis(CA),spectral quantitative analysis (ICP-AES)and X-ray photoelectron spectroscopy (XPS).With prolonging the duration of the runs,the bulk concentration of platinum in the catalyst gauzes decreased,and the contamination of iron and calcium increased.The chemical species of major components on the surface of gauzes are Pt°,Pd°,Rh°,RhO 2 and Rh 2O 3.Apparent dilution of Pt took place on the surface of gauzes whereas amount Pd and Rh relatively concentrated.The increment of Pd content in alloys led to decreasing platinum loss and the surface concentration of Rh 2O 3 which is favorable for increasing the conversion rate of ammonia.
出处
《贵金属》
CAS
CSCD
北大核心
1999年第1期1-9,共9页
Precious Metals
基金
国家自然科学基金
