铝团簇掺杂金催化CO氧化和金属钨羰基化合物对水煤气变换反应的密度泛函理论研究

发布时间：2019-01-05 04:35

【摘要】：近年来随着工业的快速发展,有毒气体CO的排放量也呈现出迅速递增的趋势。经济的发展必然带来环境的污染与破坏,但是从可持续发展的理念出发,我们必须遵循经济发展和环境污染的治理同步进行。这就要求我们在追求经济发展的过程中,一是要有效的治理有毒有污染的气体,二是要追求发展新的绿色能源,这也是本论文体现的两个重要观点。目前纳米粒子催化剂由于具有独特的催化活性受到越来越多的关注。而在选择催化剂时我们既希望它有高的催化活性,又希望它的性价比高。从这个思路出发我们选择了价钱便宜的铝来掺杂少量的金作为催化CO氧化的催化剂。这是因为,Al由于其许多化学和物理性质比如像导电性,超导性和磁性,在化学反应和纳米设备上起着非常重要的作用。尤其是Al合金团簇在应用材料科学和物理化学的传统领域方面越来越受到关注。因此在过去的几年里,Al纳米团簇掺杂金属或者非金属原子已经受到了很大的关注,而金纳米团簇在CO催化氧化CO_2上有区别于纯金的独特的催化活性,因此受到了广泛的关注。所以本论文在Gaussian09软件包下,采用密度泛函理论-DFT中的PBE的方法,对Au原子采用LANL2DZ的赝势基组,对Al、C、H、O原子采用6-31g(d,p)的基组,系统的研究了Al团簇掺杂Au原子即Al_nAu(n=1-12)催化氧化CO的LH反应机理。我们的研究结果发现Al11Au表现出了高的催化活性,决速步的能垒只有0.36 eV。氢能由于具有质量轻,易储存,燃烧产生的能量大,燃烧后的产物无污的优点而成为目前最受欢迎的绿色能源。而水煤气转换反应就是要除去氢气生产过程中的CO,进一步提高氢气的浓度。目前已经有大量关于水煤气转换反应的报道,而金属羰基化合物在水煤气转换反应中展示出了高的催化活性,但是金属羰基化合物在水煤气转换反应的研究仅限于铁族元素,有必要探索其他族元素的金属羰基化合物。本文采取密度泛函理论中的B3LYP的方法,对W原子采用LANL2DZ的赝势基组,对H原子,O原子和C原子采用6-31++g(d,p)基组。研究了W(CO)_6和W_2(CO)_(10)催化水煤气转换反应的机理。研究结果表明,二元的W_2(CO)_(10)在催化水煤气转换中有高的TOF值(3.62×10~(-12),气相;8.74×10~(-15),液相)表现出了高的催化活性,双核机理也是最好的反应机理。
[Abstract]:In recent years, with the rapid development of industry, the emission of toxic gas CO also shows a trend of rapid increase. The development of economy will inevitably lead to environmental pollution and destruction, but from the concept of sustainable development, we must follow the economic development and environmental pollution control simultaneously. This requires us to pursue the process of economic development, one is to effectively control toxic and polluting gas, the other is to pursue the development of new green energy, which is also reflected in this paper two important points of view. At present, nanoparticles have attracted more and more attention because of their unique catalytic activity. In the selection of catalyst, we hope that it has high catalytic activity and high cost-performance ratio. Based on this idea, we choose cheap aluminum as catalyst for CO oxidation by doping a small amount of gold. This is because Al plays a very important role in chemical reactions and nanoscale devices because of its many chemical and physical properties such as conductivity superconductivity and magnetism. Especially, Al alloy clusters have attracted more and more attention in the traditional fields of material science and physical chemistry. Therefore, in the past few years, Al nanoclusters doped with metal or non-metallic atoms have attracted much attention, and gold nanoclusters have unique catalytic activity different from pure gold in the catalytic oxidation of CO_2 by CO. As a result, it has received extensive attention. In this paper, the PBE method in DFT is used in the Gaussian09 software package. The pseudopotential basis set of LANL2DZ is used for Au atom, and 6-31g (DNP) basis set is used for Al,C,H,O atom. The mechanism of LH oxidation of CO catalyzed by Al cluster doped with Au atom (Al_nAu 1-12) was studied systematically. Our results show that Al11Au exhibits high catalytic activity with a barrier of only 0.36 eV.. Hydrogen energy has become the most popular green energy because of its advantages of light weight, easy storage, large energy generated by combustion and no pollution after combustion. The water gas conversion reaction is to remove CO, from the hydrogen production process and further increase the hydrogen concentration. At present, there have been a lot of reports on water gas conversion reaction, and metal carbonyl compounds show high catalytic activity in water gas conversion reaction, but the study of metal carbonyl compounds in water gas conversion reaction is limited to iron group elements. It is necessary to explore other groups of metal carbonyl compounds. In this paper, the method of B3LYP in density functional theory is used. The pseudopotential basis set of LANL2DZ is used for W atom, and 6-31 g (dapp) basis set for H atom, O atom and C atom. The mechanism of water gas conversion catalyzed by W (CO) _ 6 and W _ 2 (CO) _ (10) was studied. The results show that binary W _ S _ 2 (CO) _ (10) has high TOF value (3.62 脳 10 ~ (-12), gas phase) in catalytic water gas conversion. 8.74 脳 10 ~ (-15), liquid phase) showed high catalytic activity, and the binuclear mechanism was also the best reaction mechanism.
【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ542.4;O643.12

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