碳纳米管限域Ru基催化剂在超临界水中的制备及其活性研究

发布时间：2018-01-22 02:44

  本文关键词： 超临界水 苯酚 多壁碳纳米管 Materials studio的模拟　出处：《昆明理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着人类社会的发展和社会文明的进步,人类对新型材料和可再生能源的需求越来越高。新型材料和能源的开发利用可以极大地推进世界经济和人类社会的发展进步。所以,研发获得新型材料和可再生能源,一直以来都是研究学者关注的重要课题之一。本文即是在前人对纳米材料碳纳米管的制备和应用等研究的基础上,在超临界水中以碳纳米管为载体,在多壁碳纳米管内部负载金属Ru制备出了一种新型非均相催化剂用于超临界水中苯酚的催化气化制氢检测其活性。其主要研究结果与结论如下：(1)超临界水中制备多壁碳纳米管内部负载金属Ru(Ru/MWCNTs)催化剂。通过超临界两步水热合成法成功地将金属Ru负载在了多壁碳纳米管内部,而湿浸渍法、微波多元醇合成法、溶胶凝胶法等方法只能将负载物负载在碳纳米管表面。两者相比,多壁碳纳米管内部负载金属Ru(Ru/MWCNTs)催化剂在催化活性及选择性方面具有更广的应用。本文中一共选用了六种碳纳米管,分别成功地将4 wt%,2 wt%及1 Wt%的金属Ru负载在了六种碳纳米管的内部。(2)催化剂Ru/MWCNTs的活性研究：超临界水中苯酚的催化气化。本文中对催化剂Ru/MWCNTs进行了HR-TEM和XPS表征。HR-TEM表征结果直观地表明,无机的金属Ru粒子成功地负载到了多壁碳纳米管的内部。对于Ru/(60-100nm,5um) MWCNT催化剂,HR-TEM结果表明,金属Ru粒子在60-100nm多壁碳纳米管内部均匀分布。1wt%Ru/(60-100nm,5μm) MWCNT催化剂用于超临界水中苯酚的催化气化,其碳转化率甚至超过了商业催化剂(Ru/C,5wt%Ru). Ru/MWCNTs催化剂用于超临界水中苯酚的催化气化,可以得到70%以上的碳转化率和100%的气化率,是无催化剂状态下超临界水苯酚催化气化的近十倍左右。有趣的是,金属Ru粒子限制在碳纳米管内部,使超临界水中苯酚催化气化的产品C2H6和H2的生成量明显增加。这说明,通过超临界两步水热合成法制备出将金属Ru纳米颗粒密封在碳纳米管内部的催化剂呈现较高的催化活性和选择性。(3) Materials Studio计算机软件模拟催化剂Ru/MWCNTs制备的过程机理。本研究一共做了两个模型晶胞：300个水分子的与300个水分子和6个RuCl3分子的。计算结果表明,两个模型分子的能量随着温度的升高而升高,并且300个水分子和6个RuCl3分子的动能、势能、总能高于300个水分子的。这表明,随着温度的升高,超临界水的密度和分子间力降低,但分子间距离的增加,从而导致该氢键的数目减小,并且溶质扩散阻力变弱。从而得出结论,在低温时,RuCl3溶液分子在水中扩散并且均匀分布,随着温度的迅速升到380℃达到超临界状态,RuCl3溶液分子快速沉降,分子间的距离增加,导致RuCl32溶液分子不溶于水,使停留在碳纳米管中间的缺陷部分及两端的RuCl3溶液分子进入到碳纳米管内部。
[Abstract]:With the development of human society and the progress of social civilization. Human demand for new materials and renewable energy is increasing. The development and utilization of new materials and energy can greatly promote the development and progress of the world economy and human society. Research and development of new materials and renewable energy has been one of the most important research topics. This paper is based on the previous research on the preparation and application of carbon nanotubes (CNTs). Carbon nanotubes were used as carriers in supercritical water. A novel heterogeneous catalyst was prepared in the presence of metal Ru in multi-walled carbon nanotubes (MCNTs) for catalytic gasification of phenol in supercritical water to detect its activity. The main results and conclusions are as follows: 1). RuRu-MWCNTssupported metal catalysts were prepared in supercritical water. Metal Ru was successfully loaded in multi-walled carbon nanotubes by supercritical two-step hydrothermal synthesis. However, wet-impregnation method, microwave polyol synthesis method, sol-gel method and other methods can only load the support on the surface of carbon nanotubes. There are six kinds of carbon nanotubes (CNTs) in this paper, which have been widely used in the catalytic activity and selectivity of the multi-walled carbon nanotubes (MwCNTs) supported by metal Ruo / Ru-MWCNTs. in this paper, there are six kinds of carbon nanotubes. 4 wt% was successfully obtained respectively. 2wt% and 1Wt% metal Ru loaded on the inner of six carbon nanotubes. Study on the activity of Ru/MWCNTs catalyst:. Catalytic gasification of phenol in supercritical water. In this paper, HR-TEM and XPS characterization of the catalyst Ru/MWCNTs. HR-TEM characterization results show intuitively. Inorganic metal Ru particles were successfully loaded into the multi-walled carbon nanotubes (MCNTs). HR-TEM results showed that the Ru particles were successfully loaded into the multi-walled carbon nanotubes (MCNTs). The metal Ru particles are uniformly distributed in 60-100 nm multi-walled carbon nanotubes. 5 渭 m) MWCNT catalyst was used to catalyze the gasification of phenol in supercritical water, and its carbon conversion was even higher than that of commercial catalyst Rup / C. The catalytic gasification of phenol in supercritical water with Ru/MWCNTs catalyst for 5 wtt can yield more than 70% carbon conversion and 100% gasification rate. It is about ten times higher than the catalytic gasification of phenol in supercritical water without catalyst. Interestingly, the metal Ru particles are confined to the carbon nanotubes (CNTs). The production of C _ 2H _ 6 and H _ 2 in the products of phenol catalytic gasification in supercritical water was obviously increased. The catalysts sealed by metal Ru nanoparticles inside carbon nanotubes were prepared by supercritical two-step hydrothermal synthesis. The catalysts showed high catalytic activity and selectivity. The Materials Studio computer software was used to simulate the process mechanism of the preparation of catalyst Ru/MWCNTs. In this study, two model cells were made. Of 300 water molecules and 300 water molecules and 6 RuCl3 molecules. The energy of the two model molecules increases with the increase of temperature, and the kinetic energy and potential energy of 300 water molecules and 6 RuCl3 molecules are always higher than that of 300 water molecules. With the increase of temperature, the density and intermolecular force of supercritical water decrease, but the distance between molecules increases, which results in the decrease of the number of hydrogen bonds and the weakening of solute diffusion resistance. The molecules of RuCl3 solution diffuse and distribute uniformly in water. With the rapid rise of temperature to 380 鈩，

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