Generation 4 PAMAM-OH dendrimers were employed as templating agent for the synthesis of dendrimer-encapsulated Ru and Pt nanoparticles (Ru- or Pt-DENs). These DEN catalysts were then immobilized onto preformed mesoporous support materials (TiO₂ and SiO₂) using wet-impregnation method to produce heterogeneous catalysts. Ru- and Pt-DENs were characterized prior to immobilization using UV–vis (UV-vis) spectroscopy and high-resolution transmission microscopy (HRTEM). The average particle sizes for Ru- and Pt-DENs were determined to be 1.4 ± 0.2 and 1.7 ± 0.3 nm, respectively. Supported solid catalysts were characterized using various techniques such N₂ adsorption-desorption physisorption, powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and HRTEM. Inductive coupled plasma-optical emission spectroscopy (ICP-OES) was used for the determination of metal loading on the support. The catalytic performance of these catalysts was investigated in the selective hydrogenation of levulinic acid (LA) to produce γ-valerolactone (GVL). The highest conversion was observed when unsupported catalysts (Ru-DENs and Pt-DENs) were used for all systems studied. The Ru catalyst displayed excellent activity as compared to Pt catalysts. All catalysts showed selectivity to γ-valerolactone up to 100%.

将第4代PAMAM-OH树状聚合物用作模板剂，用于合成树状聚合物封装的Ru和Pt纳米颗粒（Ru-或Pt-DENs）。然后使用湿法浸渍法将这些DEN催化剂固定在预制的介孔载体材料（TiO ₂和SiO ₂）上，以制备非均相催化剂。在固定之前，使用紫外可见光谱（UV-vis）和高分辨率透射显微镜（HRTEM）对Ru-和Pt-DENs进行了表征。Ru-和Pt-DENs的平均粒径分别确定为1.4±0.2和1.7±0.3 nm。使用各种技术（例如N _2）对负载型固体催化剂进行了表征吸附-解吸物理吸附，粉末X射线衍射（PXRD），傅立叶变换红外（FTIR）和HRTEM。电感耦合等离子体发射光谱法（ICP-OES）用于确定载体上的金属负载。研究了这些催化剂在乙酰丙酸（LA）选择性加氢生产γ-戊内酯（GVL）中的催化性能。当未负载的催化剂（Ru-DENs和Pt-DENs）用于所有研究的系统时，观察到最高的转化率。与Pt催化剂相比，Ru催化剂显示出优异的活性。所有催化剂对γ-戊内酯的选择性均显示高达100％。