| 稀土元素对ZrO2-M2O3/MCM-41(M=La,Ce,Sm,Gd)氢转移催化活性的影响 |
| Effect of Rare Earth Element in ZrO2-M2O3/MCM-41 (M=La, Ce, Sm, Gd) on Hydrogen Transfer Reaction |
|
| 摘要: 通过浸渍法制备了5%ZrO2/MCM-41、5%ZrO2-5%M2O3/MCM-41(M=La,Ce,Sm,Gd)催化剂,考察其在苯乙酮氢转移还原生成α-苯乙醇反应中的催化活性,同时对样品进行XRD、N2吸附-脱附、吡啶吸附原位红外等表征分析,研究添加稀土金属氧化物对催化剂活性的影响机理.结果表明:ZrO2及稀土金属氧化物均以无定型态或粒度低于XRD检测限的细小晶粒较好地分散在MCM-41介孔分子筛内表面;加入稀土金属氧化物对ZrO2/MCM-41的催化活性有较大影响,催化活性按5%ZrO2-5%La2O3/MCM-41 > 5%ZrO2-5%Sm2O3/MCM-41 > 5%ZrO2-5%Gd2O3/MCM-41 > 5%ZrO2/MCM-41 > 5%ZrO2-5?2O3/MCM-41降低.这一方面归因于加入稀土金属氧化物增强了催化剂表面Zr-OH、L酸中心及B酸中心的酸性,另一方面归因于La2O3的加入使催化剂表面酸中心数目明显提高,Sm2O3、Gd2O3的加入使催化剂表面酸中心数目有所降低,而加入Ce2O3使催化剂表面酸中心数目显著减少. |
| 关键词: 氧化锆 MCM-41介孔分子筛 稀土金属氧化物 苯乙酮 氢转移反应 |
| 基金项目: |
| Abstract: 5%ZrO2/MCM-41 and 5%ZrO2-5%M2O3/MCM-41(M=La,Ce,Sm,Gd)were prepared by the impregnation method. The hydrogen transfer reduction of acetophenone with 2-propanol was investigated over these catalysts. The catalysts were characterized with XRD, N2 adsorption-desorption and FTIR spectra of adsorbed pyridine. The results show that ZrO2 and rare-earth metal oxides disperse on the surface of MCM-41 supports in an amorphous phase or as tiny crystal particles lower than the detection limit of XRD. The catalytic activity obviously varies upon loading rare-earth metal oxides on5%ZrO2-MCM-41, The activities of the catalysts decrease in the order of 5%ZrO2-5%La2O3/MCM-41 > 5%ZrO2-5%Sm2O3/MCM-41 > 5%ZrO2-5%Gd2O3/MCM-41 > 5%ZrO2/MCM-41 > 5%ZrO2-5?2O3/MCM-41. Addition of rare-earth metal oxides leads to strengthening the acidity of Zr-OH, Lewis acid sites and Brönsted acid sites on the catalyst surface. On the other hand, the addition of La2O3 can obviously enhance the number of acid sites on the catalyst surface. On the contrary, the loading of Sm2O3、Gd2O3 results in the slight decrease in the number of acid sites on the catalyst surface, especially, the addition of Ce2O3 leads to a significant drop in the number of acid sites. |
| Keywords: zirconia MCM-41 mesoporous molecular sieve rare-earth metal oxides acetophenone hydrogen transfer reaction |
| 投稿时间：2014-07-05 修订日期：2014-10-13 |
| 摘要点击次数: 1548 |
| 全文下载次数: 1894 |
| 邓冰心,张波,姜剑锋.稀土元素对ZrO2-M2O3/MCM-41(M=La,Ce,Sm,Gd)氢转移催化活性的影响[J].无机化学学报,2015,31(1):153-158. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
| Support information: |
|
|
|
|
|
|
