Palladium Nanoparticle Size Effect in 1-Hexyne Selective Hydrogenation

• Published in: JOURNAL OF PHYSICAL CHEMISTRY c, vol. 111, num. 37, p. 13933-13937
• Publication date: 2007

The structure sensitivity of a liquid-phase 1-hexyne hydrogenation was studied using monodispersed nonsupported Pd nanoparticles of 6, 8, 11, 13, and 14 nm diameter. The particles were prepared via a reverse microemulsion water/AOT/isooctane. The size was varied by the water-to-surfactant ratio. A 15-fold TOF increase was observed with increase of the particle diameter from 11 to 14 nm. For particles above 14 nm, TOF approached the value of the Pd black catalyst. It was observed that the selectivity toward 1-hexene did not vary with the particle size and was 96.5% at the conversion of 1-hexyne of 85%. The byproduct distribution was characterized by the ratio of selectivities to 2-hexenes/n-hexane and decreased 5-fold with particle diameter from 6 to 11 nm but remained constant for bigger particles. The experimental results indicate a predominance of a “geometric” nature of the size effect observed during selective 1-hexyne hydrogenation, suggesting that an ensemble of neighboring Pd surface atoms constitutes the active center responsible for hydrogenation.

Reference

• LGRC-ARTICLE-2007-023
• doi:10.1021/jp073944k
• View record in Web of Science

Record created on 2007-10-25, modified on 2016-08-08