沸石分子筛负载Pt催化剂室温催化氧化甲醛
发布时间：2019-06-20 14:35
【摘要】：作为备受关注的主要室内空气污染物,甲醛(HCHO)会对人类身体健康与环境造成巨大破坏。在消除HCHO的众多方法中,室温完全催化氧化法被认为是最有效的方法,而催化剂的设计和制备是该法的关键。由于沸石分子筛负载Pt催化剂同时具有分子筛和贵金属组分,它具备二者的组合优势,因此正逐渐成为室温完全催化氧化HCHO的最有潜力的催化剂之一。目前已经有相关沸石分子筛负载Pt催化剂低温完全催化氧化HCHO的探索工作,但在室温下完全催化氧化HCHO依然是一个巨大的挑战。本论文主要开展了一系列沸石分子筛负载Pt催化剂用于室温完全催化氧化HCHO的活性研究,着重考察了分子筛载体的酸密度、骨架外阳离子种类和硅铝比等因素对催化剂催化活性的影响。本文有四章,第一章为前言,第二章为实验部分,研究结果主要在第三与第四章。在第三章中,我们将富铝H-Beta分子筛负载Pt催化剂(Pt/H-Beta-SDS)与传统H-Beta负载Pt催化剂(Pt/H-Beta-TEA)的活性作相比,结果前者表现出更为优异的HCHO催化氧化性能。Pt/H-Beta-SDS催化剂在室温条件下(25℃)实现对400 ppm HCHO的完全催化氧化,而在同样条件下,Pt/H-Beta-TEA催化剂则需45 ℃。Pt/H-Beta-SDS如此高的HCHO室温催化活性归因于活性组分Pt具有更高的分散度和分子筛载体更加优异的HCHO吸附能力。同时,我们也对比了Pt/H-Beta-SDS, Pt/Na-Beta-SDS和Pt/K-Beta-SDS催化剂的催化性能,结果发现Pt/H-Beta-SDS的催化活性远远高于后二者,我们通过反应拆分的手段证明了Na型和K型催化剂不利于HCHO氧化为甲酸的反应步骤,从而影响整个反应活性。在第四章中,我们通过制备了一系列不同硅铝比(60,100,300,∞)与不同阳离子(H+,Na+,K+)的ZSM-5沸石分子筛,然后通过等体积浸渍法制备了上述分子筛负载1%Pt催化剂。反应结果表明,Pt/H-ZSM-5催化剂的催化活性远远高于Pt/Na-ZSM-5和Pt/K-ZSM-5催化剂,与第三章中结论一致。同时,分子筛硅铝比同样也影响着催化剂的催化活性,Pt/ZSM-5-Si催化剂具有最为优异的室温催化氧化甲醛的活性,我们把原因归结于分子筛硅铝比升高,导致催化剂疏水性也逐渐提高,这一方面增强了催化剂对HCHO的吸附能力。另一方面使得H20能更快地从催化中心脱附,从而促进反应的进行。最后,反应气氛围中引入水汽或者改变空速反应条件对上述催化剂的活性没有显著影响,而且更为重要的是催化剂的活性稳定,寿命优异。这表明这类催化剂具有较好的工业应用前景。
[Abstract]:As the main indoor air pollutant, formaldehyde (HCHO) will cause great damage to human health and environment. Among the many methods to eliminate HCHO, complete catalytic oxidation at room temperature is considered to be the most effective method, and the design and preparation of catalysts are the key to this method. Because the zeolites supported Pt catalyst has both molecular sieves and precious metal components, it has the advantages of the combination of the two, so it is gradually becoming one of the most potential catalysts for the complete catalytic oxidation of HCHO at room temperature. At present, there have been some researches on the complete catalytic oxidation of HCHO by zeolites supported Pt catalysts at low temperature, but the complete catalytic oxidation of HCHO at room temperature is still a great challenge. In this paper, a series of zeolites supported Pt catalysts for complete catalytic oxidation of HCHO at room temperature were studied, with emphasis on the effects of acid density, the type of cations outside the framework and the ratio of silicon to aluminum on the catalytic activity of the catalysts. This paper has four chapters, the first chapter is the preface, the second chapter is the experimental part, the research results are mainly in the third and fourth chapters. In chapter 3, we compare the activity of aluminum-rich H-Beta molecular sieves supported Pt catalyst (Pt/H-Beta-SDS) with that of traditional H-Beta supported Pt catalyst (Pt/H-Beta-TEA). The former shows better HCHO catalytic oxidation performance. PT / H-Beta-SDS catalyst realizes complete catalytic oxidation of 400 ppm HCHO at room temperature (25 鈩，
本文编号：2503298
[Abstract]:As the main indoor air pollutant, formaldehyde (HCHO) will cause great damage to human health and environment. Among the many methods to eliminate HCHO, complete catalytic oxidation at room temperature is considered to be the most effective method, and the design and preparation of catalysts are the key to this method. Because the zeolites supported Pt catalyst has both molecular sieves and precious metal components, it has the advantages of the combination of the two, so it is gradually becoming one of the most potential catalysts for the complete catalytic oxidation of HCHO at room temperature. At present, there have been some researches on the complete catalytic oxidation of HCHO by zeolites supported Pt catalysts at low temperature, but the complete catalytic oxidation of HCHO at room temperature is still a great challenge. In this paper, a series of zeolites supported Pt catalysts for complete catalytic oxidation of HCHO at room temperature were studied, with emphasis on the effects of acid density, the type of cations outside the framework and the ratio of silicon to aluminum on the catalytic activity of the catalysts. This paper has four chapters, the first chapter is the preface, the second chapter is the experimental part, the research results are mainly in the third and fourth chapters. In chapter 3, we compare the activity of aluminum-rich H-Beta molecular sieves supported Pt catalyst (Pt/H-Beta-SDS) with that of traditional H-Beta supported Pt catalyst (Pt/H-Beta-TEA). The former shows better HCHO catalytic oxidation performance. PT / H-Beta-SDS catalyst realizes complete catalytic oxidation of 400 ppm HCHO at room temperature (25 鈩，
本文编号：2503298
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