Influence of the pretreatment conditions on the development and performance of active sites of Pt/TiO2 catalysts used for the selective citral hydrogenation
Influence of the pretreatment conditions on the development and performance of active sites of Pt/TiO2 catalysts used for the selective citral hydrogenation
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DOI：
10.1016/j.jcat.2015.04.019
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发表时间：
2015-07-01
影响因子：
7.3
通讯作者：
Maldonado-Hodar, Francisco J.
中科院分区：
文献类型：
--
作者：
Bailon-Garcia, Esther;Carrasco-Marin, Francisco;Maldonado-Hodar, Francisco J.
采用不同的预处理工艺，考察了Pt/TiO 2催化剂的结构和化学性质的变化对催化剂催化柠檬醛加氢反应性能的影响。经过H-2预处理后，二维Pt纳米颗粒和氧空位的形成有利于Pt物种向TiO 2结构中的扩散，而经过He预处理后，形成三维Pt微晶。Pt 2-D纳米颗粒和氧空位的耦合效应强烈地增强了催化活性和柠檬醛选择性加氢为不饱和醇，通过在由高度分散的Pt纳米颗粒提供的富含氢的环境中促进柠檬醛通过末端C=O基团吸附在还原表面上。这些耦合的金属空位活性位点也形成后，合并的He/H-2预处理，然而，在以前的He处理过程中形成的三维Pt颗粒强烈降低的程度的TiO 2-Pt界面，因此表面位点浓度和催化活性。(C)2015 Elsevier Inc. All rights reserved.
The influence of pretreatment conditions of Pt/TiO2 catalysts was analyzed by different techniques and changes in the textural and chemical properties correlated with the catalytic performance in citral hydrogenation. After H-2 pretreatment, the formation of two-dimensional Pt nanoparticles and oxygen vacancies favors the diffusion of Pt species into the TiO2 structure, while three-dimensional Pt crystallites are formed after He pretreatment. The coupled effect of Pt 2-D nanoparticles and oxygen vacancies strongly enhances the catalytic activity and the selective hydrogenation of citral to unsaturated alcohols by favoring the citral adsorption on the reduced surface through the terminal C=O groups in an environment rich in hydrogen provided by the highly dispersed Pt nanoparticles. These coupled metal-vacancy active sites are formed also after a combined He/H-2 pretreatment; nevertheless, the formation of three-dimensional Pt particles during the previous He treatment strongly reduce the extent of TiO2-Pt interface and consequently the surface site concentration and the catalytic activity. (C) 2015 Elsevier Inc. All rights reserved.