Ibrahim M, Garcia M A S, Vono L L R, Guerrero M, Lecante P, Rossi L M, Philippot K
CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, F-31077-Toulouse Cedex 4, France.
Dalton Trans. 2016 Nov 28;45(44):17782-17791. doi: 10.1039/c6dt03104h. Epub 2016 Oct 21.
The solution synthesis of rhodium nanoparticles (Rh NPs) was achieved from the organometallic complex [Rh(η-CH)] under mild reaction conditions in the presence of a polymer (PVP), a monophosphine (PPh) and a diphosphine (dppb) as a stabilizer, leading to very small Rh NPs of 2.2, 1.3 and 1.7 nm mean size, with PVP, PPh and dppb, respectively. The surface properties of these nanoparticles were compared using a model catalysis reaction namely, hydrogenation of cyclohexene, first under colloidal conditions and then under supported conditions after their immobilization onto an amino functionalized silica-coated magnetite support. PVP-stabilized Rh NPs were the most active catalyst whatever the catalytic conditions as a result of a strong coordination of the phosphine ligands at the metal surface that blocks some surface atoms even after several recycles of the supported nanocatalysts and limit the reactivity of the metallic surface.
在温和的反应条件下，以聚合物（PVP）、单膦（PPh）和二膦（dppb）作为稳定剂，由有机金属配合物[Rh(η-CH)]实现了铑纳米颗粒（Rh NPs）的溶液合成，分别得到平均尺寸为2.2、1.3和1.7 nm的非常小的Rh NPs，分别对应于使用PVP、PPh和dppb的情况。使用模型催化反应，即环己烯加氢反应，首先在胶体条件下，然后在将它们固定在氨基官能化的二氧化硅包覆磁铁矿载体上后的负载条件下，比较了这些纳米颗粒的表面性质。无论催化条件如何，PVP稳定的Rh NPs都是最具活性的催化剂，这是由于膦配体在金属表面的强配位作用，即使在负载型纳米催化剂经过几次循环后，也会阻塞一些表面原子，并限制金属表面的反应性。
