光催化芳香醇的氧化及不饱和醛的还原的研究

发布时间：2018-04-10 23:23

本文选题：选择性氧化 + 芳香醇　；参考：《淮北师范大学》2017年硕士论文

【摘要】：通过不同方法制备了一系列不同形貌的In_2S_3光催化剂,考察了不同合成方法对In_2S_3形貌的影响,并研究其在可见光下选择性氧化有机物的光催化活性。通过简单的氨基酸分子辅助合成的方法合成了系列花状In_2S_3,比较分析了催化剂本体形貌以及氨基酸做为辅助试剂对其光催化活性的影响。分别采用XRD、UV-vis DRS、SEM、TEM、BET、XPS、ESR等表征技术对上述样品进行表征分析。结果表明,不同氨基酸为结晶助剂得到了不同形貌In_2S_3。在可见光下选择性氧化芳香醇到芳香醛的光催化活性结果表明,甘氨酸做为修饰剂合成的In_2S_3相较于不加氨基酸合成的样品具有较大的比较面积和较高的光生电子-空穴对的分离效率,In_2S_3选择性氧化醇到醛在加入氨基酸做结晶助剂后较不加时转化率有所提高,且具有较高的选择性。这种通过加入具有合适功能基团(如-NH2和-COOH)的氨基酸来改变材料性能的方法为实现合成有序纳米材料提供了一种廉价,绿色,有拓展性的方法。在对In_2S_3的其他合成条件的探索中发现,不同硫源对In_2S_3的生长有不同的影响,加入L-Cysteine后得到的样品结晶性较差,TU和TAA条件下合成的样品活性稍有提升。增加硫离子浓度对于In_2S_3的合成也有非常大的影响,探究合适的In/S比对于硫化铟的合成有至关重要的作用。我们采用化学还原法制备了Pt/RGO催化剂,采用乙二醇做溶剂和还原剂,通过溶剂热的方法在还原GO的同时也还原了Pt粒子,使其均匀地分散在RGO表面,且这种合成方法得到的Pt粒子粒径相对均匀。在将其用于肉桂醛选择加氢反应中发现,通过金属Pt修饰剂修饰后的催化剂的具有较高的转化率,这可能是由于Pt粒子的加入后使C=O键得到了弱化。这一反应在光催化领域中还鲜有报道,更多的实验条件和反应机理还有待于进一步的研究。
[Abstract]:A series of In_2S_3 photocatalysts with different morphologies were prepared by different methods. The effects of different synthesis methods on the morphology of In_2S_3 were investigated, and the photocatalytic activity of In_2S_3 photocatalysts for selective oxidation of organic compounds under visible light was studied.A series of flower Ins _ 2s _ 3 were synthesized by a simple method of amino acid molecular assisted synthesis. The effects of catalyst bulk morphology and amino acid as auxiliary reagent on its photocatalytic activity were compared and analyzed.The samples were characterized by means of XRDX UV-vis UV-vis DRSX SEMSTM Tem BETX XPS ESR and so on.The results showed that different morphologies of in _ 2s _ s _ s _ s _ 3s _ 3 were obtained by using different amino acids as crystal auxiliaries.The photocatalytic activity of selective oxidation of aromatic alcohols to aromatic aldehydes under visible light shows that,The In_2S_3 synthesized by glycine as modifier has a larger comparative area and higher separation efficiency of photogenerated electron-hole pairs than the sample synthesized without amino acids. In _ 2S _ 3 selective oxidation of alcohols to aldehydes helps to crystallize in addition of amino acids.The conversion rate was increased after the addition of the agent.And it has high selectivity.This method by adding amino acids with suitable functional groups (such as -NH _ 2 and -COOH) to change the properties of the materials provides a cheap, green and extensible method for the synthesis of ordered nanomaterials.In the exploration of other synthetic conditions of In_2S_3, it was found that different sulfur sources had different effects on the growth of In_2S_3, and the activity of the samples synthesized under the conditions of TU and TAA was slightly improved after the addition of L-Cysteine.Increasing the concentration of sulfur ion also has a great influence on the synthesis of In_2S_3. It is very important to explore the appropriate In/S ratio for the synthesis of indium sulfide.The Pt/RGO catalyst was prepared by chemical reduction method. Ethylene glycol was used as solvent and reductant. The Pt particles were reduced by solvothermal method, and the Pt particles were dispersed uniformly on the surface of RGO.The particle size of Pt particles obtained by this synthesis method is relatively uniform.In the selective hydrogenation of cinnamaldehyde, it was found that the catalyst modified by Pt had a higher conversion, which may be due to the weakening of the C-O bond after the addition of Pt particles.This reaction is rarely reported in the field of photocatalysis, and more experimental conditions and reaction mechanisms need to be further studied.
【学位授予单位】：淮北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.251

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