聚多巴胺功能化硅胶沉积单分散Pd纳米粒子的简易原位合成及用作醇需氧氧化反应的多相可循环使用的纳米催化剂

摘要

本文报道了一种不使用任何稳定剂或还原剂, 原位合成硅胶/聚多巴胺复合物(SiO2/PDA)负载的Pd纳米颗粒(Pd NPs)的简易方法. 该方法先将PDA涂覆的SiO2颗粒浸在Pd镀液中, 然后利用PDA中含N基团的还原能力将Pd物种原位还原为纳米簇合物. 并采用高分辨透射电镜、前场扫描电镜、能量散射谱、X射线衍射、X射线光电子能谱、诱导耦合等离子体和红外光谱等手段对所得纳米复合物的结构、形貌和物化性质进行了表征. 被PDA基团锚合的Pd NPs具有显著的小颗粒(30-40 nm)特性. 作为一个可循环使用的纳米催化剂, SiO2/PDA/Pd NPs在醇的需氧氧化反应中表现出高活性. 另外, 催化剂经回收和多次重复使用时未出现明显的失活.%This paper describes a facile in-situ synthesis of palladium nanoparticles (Pd NPs) on silica gel/polydopamine composite (SiO2/PDA) without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA-coated SiO2particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA's N-containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, inductively coupled plasma and Fourier-transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size (30-40 nm). SiO2/PDA/Pd NPs exhibited high catalytic activ-ity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.