Tuning selectivity in catalysis by controlling particle shape
Tuning selectivity in catalysis by controlling particle shape
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DOI：
10.1038/nmat2371
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发表时间：
2009-02-01
期刊：
影响因子：
41.2
通讯作者：
Zaera, Francisco
中科院分区：
文献类型：
--
作者：
Lee, Ilkeun;Delbecq, Francoise;Zaera, Francisco
选择性生成顺式烯烃的催化过程将有助于最大限度地减少食用油部分氢化过程中不健康反式脂肪的产生。在这里，我们在模型系统研究的基础上，报告了这样一个过程的设计。在单晶上的程序升温脱附数据表明，铂的(111)面促进了反式烯烃异构化为顺式烯烃，而这种选择性在更开放的表面上是相反的。量子力学计算表明，顺式烯烃在氢饱和的铂(111)表面上的额外稳定性可能是由于表面重建程度较低，这一因素在紧密堆积的铂表面上的吸附是重要的。由分散的四面体铂纳米颗粒制成的催化剂的动力学数据证实了金属(111)面上反式异构化为顺式异构化的选择性促进。我们的工作为如何通过控制催化颗粒的形状来控制催化选择性提供了一个例子。
A catalytic process for the selective formation of cis olefins would help minimize the production of unhealthy trans fats during the partial hydrogenation of edible oils. Here we report on the design of such a process on the basis of studies with model systems. Temperature programmed desorption data on single crystals showed that the isomerization of trans olefins to their cis counterparts is promoted by (111) facets of platinum, and that such selectivity is reversed on more open surfaces. Quantum mechanics calculations suggested that the extra stability of cis olefins seen on hydrogen-saturated Pt(111) surfaces may be due to a lesser degree of surface reconstruction, a factor found to be significant in the adsorption on close-packed platinum surfaces. Kinetic data using catalysts made out of dispersed tetrahedral Pt nanoparticles corroborated the selective promotion of the trans-to-cis isomerization on the (111) facets of the metal. Our work provides an example for how catalytic selectivity may be controlled by controlling the shape of the catalytic particles.