UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxon, Didcot OX11 0FA, UK.
Faraday Discuss. 2018 Sep 3;208(0):443-454. doi: 10.1039/c7fd00216e.
The use of sol-immobilisation to prepare supported metal nanoparticles is an area of growing importance in heterogeneous catalysis; it affords greater control of nanoparticle properties compared to conventional catalytic routes e.g. impregnation. This work, and other recent studies, demonstrate how the properties of the resultant supported metal nanoparticles can be tailored by adjusting the conditions of colloidal synthesis i.e. temperature and solvent. We further demonstrate the applicability of these methods to the hydrogenation of nitrophenols using a series of tailored Pd/TiO2 catalysts, with low Pd loading of 0.2 wt%. Here, the temperature of colloidal synthesis is directly related to the mean particle diameter and the catalytic activity. Smaller Pd particles (2.2 nm, k = 0.632 min-1, TOF = 560 h-1) perform better than their larger counterparts (2.6 nm, k = 0.350 min-1, TOF = 370 h-1) for the hydrogenation of p-nitrophenol, with the catalyst containing smaller NPs found to have increased stability during recyclability studies, with high activity (>90% conversion after 5 minutes) maintained across 5 catalytic cycles.
利用固溶体固定法制备负载型金属纳米粒子是多相催化中一个日益重要的领域；与传统的催化方法（例如浸渍法）相比，它能更好地控制纳米粒子的性质。这项工作和其他最近的研究表明，通过调整胶体合成的条件（例如温度和溶剂），可以调整所得负载型金属纳米粒子的性质。我们进一步证明了这些方法在使用一系列经过调整的负载量为 0.2wt%的 Pd/TiO2催化剂进行硝基苯酚加氢反应中的适用性。在这里，胶体合成的温度与平均粒径和催化活性直接相关。较小的 Pd 颗粒（2.2nm，k = 0.632min-1，TOF = 560h-1）的催化性能优于较大的 Pd 颗粒（2.6nm，k = 0.350min-1，TOF = 370h-1），对于 p-硝基苯酚的加氢反应，在可重复使用性研究中，含有较小 NPs 的催化剂具有更高的稳定性，在 5 个催化循环中保持了高活性（5 分钟后转化率>90%）。
