摘要
以IR光谱和程序升温硫化方法对近年来催化研究和应用较多的几种杂多酸在H2S作用下的硫化过程进行了研究．在SiW12、PW12和PMo12三种杂多酸中，PMo12最易发生硫化作用，其两种桥氧比端氧易硫化的倾向也最大．PW12次之．在初始硫化阶段，杂多酸中的部分氧原子在维持其Keggin骨架结构情况下被硫原子取代．在这一条件下硫氧交换是可逆的．对于PMo12，可维持其Keggin结构的温度接近室温，对于SiW12和PW12，该温度在673K～723K之间．当超过这一特定温度时，杂多酸的硫化作用不再可逆，深度硫化作用可能伴随Keggin骨架结构的解体．
The sulfUIization of several heteropoly acids (HPA), which have been applled as catalysts frequently in recent years, have been studied by IR spectra and temperature programmed sulPhurization technology. The result showed that sulphurization of PMo12 is the easiest one among the three kinds of HPA (PMo12, PW12, SiW12). In addition,The trend that the two kinds of bridged oxygen in HPA were substituted by sulfur atoms prior to terAnnal oxygen, is PMo12 >PW12 >SiW12. In the iintial stage of sulphUrization,some of oxygen atoms in HPA are substituted by sulfur atoms reversibly and the Keggin structure has been preserved during this process. For PW12 and SiW12, the Keggin structure can be preserved until the sulphurization temPerature has been raised to 673K,and for the PMo12, this temPerature is near room temPerature. When the temPerature exceed those mentioned above in the sulphUIization process, the exchange between sulfur and oxygen become irreversible, and deep sulphurization of HPA 1nay be accompanied with disintegration of the Keggin anion skeleton.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1996年第2期124-129,共6页
Acta Physico-Chimica Sinica
基金
中国博士后科学基金
关键词
硫化作用
氧-硫交换
杂多酸
催化剂
Heteropoly anion, Sulphurization, Oxygen-sulfur exchange
