Preparation of supported mono- and bimetallic nanoparticles by Supercritical Fluid Reactive Deposition (SFRD)

与传统催化剂相比，纳米颗粒和纳米合金具有独特的性能和更强的催化活性，在催化应用中受到越来越多的关注。到目前为止，单金属和双金属纳米颗粒通常是通过传统的湿浸渍技术制备的，这种技术存在一些缺点，例如对所得产品性能的控制不好。与此相反，SFRD技术为制备单金属和双金属纳米颗粒提供了一种替代和有前途的方法，因为它可以控制颗粒的大小和分布、均匀性和浓度。单组分SFRD过程包括三个步骤：前驱体在scCO2中的溶解，前驱体在载体上的吸附或吸附以及将吸附的前驱体转化为其金属形式。在SFRD合成双金属纳米粒子的过程中，自然产生了同步沉积和顺序沉积两种方法。因此，在拟议的项目中，各种单金属和双金属纳米颗粒将沉积在不同的支撑上。与单组分SFRD类似，在同时SFRD中，前驱体在存在scCO2的情况下在载体上的吸附是至关重要的，将应用实验和理论方法进行研究。因此，本项目的目标是通过SFRD制备负载的单金属和双金属纳米颗粒，并研究前驱体和衬底性质、吸附行为和还原方法对金属负载、颗粒大小和分布的影响。

Due to unique properties and enhanced catalytic activities compared to conventional catalysts, nanoparticles and nanoalloys have been attracting increasing attention in catalytic applications. So far, mono- and bi-metallic nanoparticles were usually prepared by using conventional wet impregnation techniques that are associated with a few drawbacks such as poor control of the obtained product properties. In opposite thereto, the SFRD technique enables an alternative and promising method for the preparation of mono- and bimetallic nanoparticles, since it provides to control the particle size and distribution, homogeneity and concentration. The single component SFRD process consists of three steps that are: the dissolution of a precursor in scCO2, adsorption or sorption of the precursor onto support and the conversion of the adsorbed precursor to its metal form. Two approaches naturally arise in order to synthesize bimetallic nanoparticles using SFRD, which are simultaneous and sequential deposition. Therefore, within the proposed project, various mono- and bimetallic nanoparticles will be deposited on different supports. Similar to single component SFRD, in simultaneous SFRD the adsorption of precursor(s) on the support in the presence of scCO2 is of crucial importance and will be investigated applying experimental and theoretical approaches. Thus, the objectives of this proposed project are to prepare supported mono- and bimetallic nanoparticles via SFRD and to investigate the influence of precursor and substrate properties, adsorption behavior and reduction method on metal loading, particle size and distribution.