Cu-Ni纳米晶形貌可控合成及其催化性能研究

发布时间：2018-05-31 23:05

  本文选题：Cu-Ni纳米晶 + 可控合成　； 参考：《东南大学》2017年硕士论文

【摘要】：由于可控合成双金属纳米材料可应用于非均相催化,低温燃料电池技术等很多领域,其研究正成为是一个中要热门的课题。相比于单金属催化剂,双金属催化剂可以通过不同金属之间电子转移,局部协同环境,晶格张力,表面元素的分布有更多的机会改变其催化性能。本文通过控制包覆剂、反应时间、温度等因素,利用溶剂热法合成不同形貌的Cu-Ni双金属纳米品,考察了纳米晶形成过程的不同因素以及形成机理。此外,还通过邻二甲苯催化氧化实验来探究不同形貌的纳米晶的催化活性。在Cu-Ni双金属纳米晶制备过程中,利用聚乙烯吡咯烷酮(PVP)为包覆剂、苯胺为还原剂在苯甲醇溶液中进行,可控合成出的六边形纳米片和纳米线,它们形貌比较规整、分散性很好,具有高结晶度。在合成过程中发现,当PVP溶度为0.2 mM,即较低时,最终得到的纳米粒子为六边形纳米片;而当PVP溶度升高到0.4 mM时,最终得到的纳米粒子为纳米线。同时,温度也是一个比较重要的影响因素,当温度低于170 ℃时纳米粒子无法形成;而当温度高于220 ℃时,纳米粒子的成核和生长速度会急剧加快,造成最终纳米粒子的聚合。在催化氧化实验中,通过三种方法制备不同的催化剂来比较Cu-Ni双金属纳米晶的催化性能。实验表明,与传统的浸渍法相比,超声法制备催化剂对邻二甲苯催化燃烧反应表现出比浸渍法更好的活性,特别是活性相为Cu-Ni纳米线的催化剂拥有最优的活性。同时载体为介孔分子筛(MZSM-5)催化剂负载11 wt%的Cu-Ni纳米线活性相表现出更优的活性。通过比较T90的数值,可以发现纳米线催化剂的温度大约比浸渍法催化剂低40 ℃,比原位法催化剂低70 ℃。MZSM-5负载的纳米线具有优异的活性主要是超声过程中催化剂会形成一种类似于榴莲状的表面结构,导致了催化剂活性要优于浸渍法制备的催化剂。
[Abstract]:Due to the controllable synthesis of bimetallic nanomaterials can be used in heterogeneous catalysis, low-temperature fuel cell technology and many other fields, its research is becoming a hot topic. Compared with monometallic catalysts, bimetallic catalysts have more opportunities to change their catalytic performance through electron transfer between different metals, local synergistic environment, lattice tension and distribution of surface elements. In this paper, Cu-Ni bimetallic nanocrystals with different morphologies were synthesized by controlling the coating agent, reaction time and temperature. The different factors and formation mechanism of nanocrystalline formation were investigated. In addition, the catalytic activity of nanocrystals with different morphologies was investigated by catalytic oxidation of o-xylene. In the preparation of Cu-Ni bimetallic nanocrystals, hexagonal nanowires and nanowires were synthesized by using polyvinylpyrrolidone (PVP) as coating agent and aniline as reducing agent in benzol solution. High crystallinity. It was found that when the solubility of PVP was 0. 2 mm, the final nanoparticles were hexagonal nanoparticles, while when the solubility of PVP increased to 0. 4 mm, the final nanoparticles were nanowires. At the same time, temperature is also an important factor, when the temperature is below 170 鈩，

本文编号：1961695