摘要
采用化学气相沉积法,研究了五氧化二磷对Hβ分子筛酸性和孔结构的改性.XRD研究显示,没有新的物相生成.TPD和IR测试表明,五氧化二磷与Hβ分子筛中B r¨onsted酸性位存在着强相互作用,有新的弱酸中心产生.通过改性,强酸中心降低,弱酸中心增加,同时发现,被磷物种覆盖的部分酸中心经过氮气的吹扫能够得到恢复.N2吸附—脱附等温线研究表明,样品的N2吸附—脱附等温线为Ⅰ型和Ⅳ型的复合体.由于磷物种对孔道的堵塞,改性Hβ分子筛样品的比表面积、孔容以及平均孔半径均减小.以正癸烷异构化为模型反应对改性样品的异构化催化性能进行了考察,结果发现,改性后P t/Hβ催化剂上正癸烷异构化性能有明显的改善.
The structure and the acidic properties of Hβ zeolite were modified with phosphorus pentoxide added by using chemical vapour deposition method. XRD showed no new crystalline phase existed in the modified samples. The results of NH3-TPD and IR showed that phosphorus pentoxide reacted with both Br/Snsted acid sites and terminal SiOH groups. Strong Broensted sites decreased and new weak acid sites were formed. The nitrogen adsorption-desorption measurement suggested that the isothermal type of all samples was a combination of type Ⅰ and type Ⅳ. BET surface areas, pore volume, micropore volume and average pore diameter decreased after modified with phosphorus pentoxide by chemical vapour deposition. The catalytic properties of the phosphorus modified zeolites were characterized in the hydroisomerization reaction of n-decane.
出处
《南开大学学报（自然科学版）》
CAS
CSCD
北大核心
2005年第6期22-27,共6页
Acta Scientiarum Naturalium Universitatis Nankaiensis
基金
国家自然科学基金资助项目(20233030)
关键词
Hβ
酸性
五氧化二磷
化学气相沉积
改性
Hβ
acidity
phosphorus pentoxide
chemical vapour deposition, modification
