Pd catalysts supported on MnCeOx mixed oxides and their catalytic application in solvent-free aerobic oxidation of benzyl alcohol: Support composition and structure sensitivity
Pd catalysts supported on MnCeOx mixed oxides and their catalytic application in solvent-free aerobic oxidation of benzyl alcohol: Support composition and structure sensitivity
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DOI：
10.1016/j.jcat.2011.06.021
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发表时间：
2011-10-06
影响因子：
7.3
通讯作者：
Yang, Yanhui
中科院分区：
文献类型：
--
作者：
Chen, Yuanting;Zheng, Huijian;Yang, Yanhui
结晶和非晶MnCeOx载体分别通过共沉淀和氧化还原沉淀法合成。Pd随后沉积通过一个简单的微波辅助多元醇还原程序，导致形成高度分散的Pd纳米团簇。MnCeOx载体在苯甲醇有氧氧化反应中的催化活性和选择性均比纯MnOx和CeO 2有显著提高。在Pd/7 Mn 3Ce-C（15，235 h（-1））和Pd/7 Mn 3Ce-A（14，438 h（-1））上实现了最高的qTOF（准转换频率），并且可以在五个连续反应运行中保持活性。Pd作为单一活性组分，Pd、MnOx和CeO 2之间的协同作用导致催化活性增强。Pd活性中心的良好可及性和Pd-0的高表面浓度有助于在结晶MnCeOx负载的Pd催化剂上的高初始反应速率。非晶态MnCeOx负载Pd催化剂由于氧化还原性能和氧迁移率之间的相互促进而表现出增强的催化剂稳定性。(C)2011 Elsevier Inc. All rights reserved.
Both crystalline and amorphous MnCeOx supports were synthesized by co-precipitation and redox precipitation methods, respectively. Pd was subsequently deposited by an easy microwave-assisted polyol reduction procedure, leading to the formation of highly dispersed Pd nanoclusters. MnCeOx supports were remarkably enhanced in both catalytic activity and selectivity in the aerobic oxidation of benzyl alcohol, compared with pure MnOx and CeO2. The highest qTOFs (quasi-turnover frequencies) were achieved over Pd/7Mn3Ce-C (15,235 h(-1)) and Pd/7Mn3Ce-A (14,438 h(-1)), and the activity could be maintained over five consecutive reaction runs. Pd acts as a single active component, and the synergetic interactions among Pd, MnOx, and CeO2 result in enhanced catalytic activity. Good accessibility of the Pd active sites and a high surface concentration of Pd-0 contribute to the high initial reaction rate over crystalline MnCeOx-supported Pd catalyst. Amorphous MnCeOx-supported Pd catalyst exhibits enhanced catalyst stability due to mutual promotion between redox properties and oxygen mobility. (C) 2011 Elsevier Inc. All rights reserved.