Zhang Jianming, Chen Guozhu, Guay Daniel, Chaker Mohamed, Ma Dongling
Institut National de la Recherche Scientifique, INRS-Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
Nanoscale. 2014 Feb 21;6(4):2125-30. doi: 10.1039/c3nr04715f. Epub 2013 Nov 11.
To enhance the catalytic activity of gold nanoparticles (AuNPs) for the hydrogenation of nitro-aromatic chemicals, Pt was introduced into AuNPs to form "bare" PtAu alloy NPs using a physical approach, pulsed laser ablation in liquid (PLAL), on single metal-mixture targets. These PLAL-NPs are deemed to favor catalysis due to the absence of any surfactant molecules on their unique "bare and clean" surface. The PLAL-NPs were facilely assembled onto CeO2 nanotubes (NTs) by simply mixing them without conducting any surface functionalization, representing another advantage of these NPs. Their catalytic activity was assessed in 4-nitrophenol (4-NP) hydrogenation. The reaction catalyzed by alloy-NP/CeO2-NT catalysts demonstrates a remarkably higher reaction rate in comparison with that catalyzed by pure Au and Pt NPs, and other similar Au and Pt containing catalysts reported recently. A "volcano-like" catalytic activity dependence of the alloy NPs on their chemical composition suggests a strong synergistic effect between Au and Pt in the 4-NP reduction, far beyond the simple sum of their individual contributions. It leads to the significantly enhanced catalytic activity of Pt30Au70 and Pt50Au50 alloy NPs, outperforming not only each single constituent, but also their physical mixtures and most recently reported AuNP based nanocatalysts. The favorable d-band center shift of Pt after alloying, and co-operative actions between Pt clusters and nearby Au (or mixed PtAu) sites were proposed as possible mechanisms to explain such a strong synergistic effect on catalysis.
为提高金纳米颗粒（AuNPs）对硝基芳烃化合物氢化反应的催化活性，采用物理方法——液体中的脉冲激光烧蚀（PLAL），在单一金属混合靶材上，将铂引入AuNPs中以形成“裸”PtAu合金纳米颗粒。这些通过PLAL制备的纳米颗粒因其独特的“裸露且洁净”表面不存在任何表面活性剂分子，被认为有利于催化反应。通过简单混合，无需进行任何表面功能化处理，就能轻松地将这些通过PLAL制备的纳米颗粒组装到二氧化铈纳米管（NTs）上，这体现了这些纳米颗粒的另一个优势。在4-硝基苯酚（4-NP）氢化反应中评估了它们的催化活性。与纯Au和Pt纳米颗粒以及最近报道的其他类似含Au和Pt的催化剂相比，合金纳米颗粒/二氧化铈纳米管催化剂催化的反应显示出显著更高的反应速率。合金纳米颗粒的催化活性对其化学成分呈现出“火山状”的依赖性，这表明在4-NP还原反应中Au和Pt之间存在强烈的协同效应，远远超过它们各自贡献的简单加和。这导致Pt30Au70和Pt50Au50合金纳米颗粒的催化活性显著增强，不仅优于每种单一成分，还优于它们的物理混合物以及最近报道的基于AuNP的纳米催化剂。合金化后Pt有利的d带中心位移以及Pt团簇与附近Au（或混合的PtAu）位点之间的协同作用被认为是解释这种对催化反应强烈协同效应的可能机制。
