摘要
采用固态离子交换法在沸石中直接引进Ｃｕ（Ｉ）活性中心，ＣｕＣｌ分子在Ｈβ沸石中与Ｈ＋交换和在沸石内表面单层分散两个过程同时发生，负载阈值为２１．２％（ＣｕＣｌ％），调节ＣｕＣｌ和Ｈβ的配比，可得到从桥羟基被部分交换到所有羟基被完全交换的ＣｕＣｌ／Ｈβ催化剂．以ＣＯ为探针分子，研究了Ｃｕ＋的吸附特性．结果表明，在沸石中Ｃｕ＋存在两类阳离子位．从沸石中Ｃｕ＋的配位空位数、Ｃｕ＋周围的电子环境和电子亲和性，探讨了Ｃｕ＋位于不同位置时Ｃｕ—Ｃ＝Ｏ的成键与ＣＯ吸收峰差别的原因．
CuCl can be directly exchanged and highly dispersed into zeolite H without formation of Cu2+ by solid\|state ion exchange method at 573 K, 1.0 10-3 Pa for 24 h. CuCl/H systems with different CuCl ratio were prepared; the critical monolayer dispersion capacity into H of CuCl was 21.2% ( CuCl % ), high dispersion of cuprous chloride molecules can result in more active sites for catalysis and adsorption. From IR in\|situ results, it was found that solid\|state ion exchange process of cuprous ions and dispersion process of cuprous chloride molecules occur simultaneously during solid\|state ion exchange. When the ratio of CuCl is \{0.35% ( CuCl% ),\} ion\|exchange of Cu+ predominated and the intensity of the -OH at 3597 cm-1 band decreases, Cu+ ions are mainly located at SI sites. In contrast, when the ratio of CuCl is 5% and 15%, the bands at 3597, 3635, 3740 cm-1 disappear totally. The XRD results indicated that all CuCl molecules are in monolayer dispersion. The IR spectra of
出处
《分子催化》
EI
CAS
CSCD
北大核心
1999年第2期115-120,共6页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金
关键词
HΒ沸石
氯化亚铜
沸石
羰基化
催化剂
Solid\|state ion exchange, CuCl, Zeolite, Monolayer dispersion CuCl/H systems with CO adsorbed showed that the intensity of the bands at 2152 and 2157 cm-1 increase with increasing CuCl ratio, more Cu+ ions are located at Ssites. The carbonyls
