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Tuning the Catalytic Activity and Selectivity of Pd Nanoparticles Using Ligand-Modified Supports and Surfaces
ACS Omega ( IF 3.7 ) Pub Date : 2017-09-20 00:00:00 , DOI: 10.1021/acsomega.7b00836
Fernanda Parra da Silva 1 , Jhonatan Luiz Fiorio 1 , Liane Marcia Rossi 1
Affiliation  

The organic moiety plays an essential role in the design of homogeneous catalysts, where the ligands are used to tune the catalytic activity, selectivity, and stability of the transition metal centers. The impact of ligands on the catalytic performance of metal nanoparticle catalysts is still less understood. Here, we prepared supported nanoparticle (NP) catalysts by the immobilization of preformed Pd NPs on the ligand-modified silica surfaces bearing amine, ethylenediamine, and diethylenetriamine groups. After excluding any size effect, we were able to study the influence of the ligands grafted on the support surface on the catalytic activity of the supported nanoparticles. Higher activity was observed for the Pd NPs supported on propylamine-functionalized support, whereas the presence of ethylenediamine and diethylenetriamine groups was detrimental to the activity. Upon the addition of excess of these amine ligands as surface modifiers, the hydrogenation of alkene to alkane was fully suppressed and, therefore, we were able to tune Pd selectivity. The selective hydrogenation of alkynes into alkenes, although a considerable challenge on the traditional palladium catalysts, was achieved here for a range of alkynes by combining Pd NPs and amine ligands.

中文翻译:

使用配体修饰的载体和表面调节Pd纳米粒子的催化活性和选择性

有机部分在均相催化剂的设计中起着至关重要的作用,其中配体用于调节过渡金属中心的催化活性,选择性和稳定性。配体对金属纳米颗粒催化剂的催化性能的影响仍然很少被理解。在这里,我们通过将预先形成的Pd NPs固定在带有胺,乙二胺和二亚乙基三胺基团的配体改性二氧化硅表面上来制备负载型纳米颗粒(NP)催化剂。排除任何尺寸效应后,我们能够研究接枝到载体表面上的配体对负载型纳米颗粒催化活性的影响。丙胺官能化载体上负载的Pd NPs的活性更高,乙二胺和二亚乙基三胺基团的存在不利于活性。在添加过量的这些胺配体作为表面改性剂后,烯烃加氢成烷烃被完全抑制,因此,我们能够调节Pd的选择性。炔烃选择性加氢成烯烃,尽管对传统的钯催化剂提出了巨大挑战,但在此通过结合Pd NP和胺配体实现了一系列炔烃的选择。
更新日期:2017-09-20
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