摘要
以SnCl2为锡源,通过添加含乙二胺四乙酸(EDTA)的SnCl2溶液和直接采用SnCl2溶液两种方式对Ag催化剂载体进行改性,制得表面改性的Ag催化剂载体,再通过浸渍法制得负载Ag催化剂;采用SEM,TEM,XRD等方法对改性载体及Ag催化剂进行表征,并考察了表面改性的载体对Ag催化剂性能的影响。研究结果表明,用SnCl2-EDTA溶液处理Ag催化剂载体后,在载体表面形成大量的SnO2晶体颗粒,用该改性载体制得的Ag催化剂具有很高的活性和稳定性;表征结果显示,SnO2晶粒对活性组分Ag的电子结构有调变作用,对Ag粒子在载体表面的热迁移有隔离阻碍作用,这是该改性载体制得的Ag催化剂具有优异活性和稳定性的主要原因;由SnCl2溶液直接处理Ag催化剂载体只形成较少量的SnO2晶粒,制得的Ag催化剂活性变差,选择性略有降低。
The support of the silver catalyst, which was used in ethylene epoxidation to ethylene oxide, was treated with SnC12 solution or SnC12 solution containing ethylene diamine tetraacetic acid （EDTA） by an impregnation method. And then the supported silver catalysts were prepared by an impregnation method. The modified supports and the silver catalysts were characterized by means of SEM, TEM and XRD. The effect of the Sn-modified supports on the performances of the silver catalysts in the epoxidation was studied. The results showed that, after the treatment with SnCI^-EDTA solution, lots of the crystal tin oxide particles were formed on the support surface. The SnO2 particles could modulate the electronic structure of the active component （silver） and could hinder the heat migration of the silver particles on the support surface, which was the main cause of the excellent activity and stability of the silver catalyst with the Sn-modified support. After the treatment with SnC12 solution, only a few SnO2 particles were formed on the support surface, and the activity of the silver catalyst with the modified support was even lower while the selectivity decreased slightly.
出处
《石油化工》
CAS
CSCD
北大核心
2011年第12期1292-1296,共5页
Petrochemical Technology
关键词
银催化剂
氯化亚锡
载体改性
环氧化
环氧乙烷
silver catalyst
stannous chloride
support modification
epoxidation
ethylene oxide
