Ag、Pt贵金属纳米结构调控与催化性能研究
发布时间：2018-07-29 14:16
【摘要】：双金属纳米材料由两种不同金属元素构成，与单金属材料相比，双金属纳米材料不是简单的金属性能相加，而是会衍生出更多的优异性能。同时，由于双金属纳米材料的结构和成分可调，以及特殊的物理化学性质，从而赋予了这种纳米材料在燃料电池、生物诊断、表面拉曼增强以及催化剂等方面的广泛的应用前景。因此，如何制备结构可调控的双金属纳米材料，对于双金属纳米材料的性能改善具有很重大的意义。本论文成功地制备出在钛酸盐纳米线表面修饰不同结构的Ag/Pt双金属纳米结构的纳米复合材料，研究了影响其双金属纳米结构以及组分的因素以及不同双金属结构的纳米复合材料的催化性能。主要的研究内容以及取得的成果如下： 1、TiO2NW@空心Ag*/Pt纳米复合材料：首先，将银纳米颗粒（AgNP）修饰在钛酸盐纳米线（TiO2NW）表面，然后在AgNP表面上包覆一层纳米级的一氧化铂（PtO），即成功的制备出TiO2NW@Ag*NP@PtO纳米复合材料。以Ag*NP为模板，将银从银核外扩到壳层以及还原，制备出TiO2NW@空心Ag*/Pt纳米复合材料。探讨铂源K2PtCl4对Ag*NP@PtO纳米结构的影响，以及TiO2NW@空心Ag*/Pt纳米复合材料的银铂比的间接影响。同时，探讨了Ag*NP@PtO与H2O2反应时间对TiO2NW@空心Ag*/PtOx及TiO2NW@空心Ag*/Pt纳米复合材料的结构影响。PtOx可以通过NaBH4还原制备出单质铂。结果表明，，改变铂源的加入量可以实现对Ag*NP@PtO纳米结构的PtO厚度的可控制备以及间接调控TiO2NW@空心Ag*/Pt纳米复合材料的银铂比；改变Ag*NP@PtO与H2O2反应时间可以实现空心Ag*/Pt纳米结构的可控制备。通过催化对硝基苯酚（4-NP）氢化还原实验，表明随着TiO2NW@Ag*NP@Pt纳米复合材料的Pt壳层的厚度增加，催化4-NP氢化还原的转化率反而降低，这是由于银的裸露程度降低，使可进入双金属界面的减少。随着TiO2NW@Ag*NP@PtO纳米复合材料与H2O2反应时间的逐渐增加，催化4-NP活性随着先增加后降低，这是由于银纳米颗粒的外扩，使铂的催化位点以及可进入的双金属界面的发生改变。并且，TiO2NW具有一维的结构以及与双金属纳米材料的不同水溶性，有利于催化性能以及可重复利用率的提高。TiO2NW@空心Ag*/Pt纳米复合材料具有优异的催化性能，同时对其多次循环催化4-NP实验也证明其具有良好的可重复利用率。 2、TiO2NW@空心Ag/AgPt纳米复合材料：首先，在TiO2NW表面上修饰上AgNP，然后通过铂前驱体H2PtCl6与AgNP的置换反应以及抗坏血酸的共还原反应，成功地制备出TiO2NW@空心Ag/AgPt纳米复合材料。探讨了不同浓度H2PtCl6对空心Ag/AgPt纳米结构、空心结构的表面结构以及AgPt合金比例的影响。结果表明，调控浓度H2PtCl6可实现具有不同AgPt合金比例以及修饰不同结构的空心Ag/AgPt纳米结构的可控制备。通过催化对硝基苯酚（4-NP）氢化还原实验，表明片状空心结构TiO2NW@空心Ag/AgPt纳米复合材料具有优异的催化性能，这是由于片状空心结构具有大的比表面积、具有可进入的AgPt双金属界面以及TiO2NW具有不同的水溶性。同时，通过多次循环催化4-NP实验，表明片状空心结构的TiO2NW@空心Ag/AgPt纳米复合材料具有优异的可重复利用率，这是由于TiO2NW具有一维纳米结构。
[Abstract]:Bimetal nanomaterials are made up of two different metallic elements. Compared with single metal, bimetallic nanomaterials are not simple metal properties, but will derive more excellent properties. At the same time, due to the adjustable structure and composition of bimetal nanomaterials, as well as special physical and chemical properties, the nanomaterials endow the nanoscale. Materials are widely used in fuel cells, biological diagnosis, surface Raman enhancement and catalysts. Therefore, how to prepare structural adjustable bimetal nanomaterials is of great significance for the performance improvement of bimetallic nanomaterials. This paper has successfully prepared different structures on the surface modification of titanate nanowires. The Ag/Pt bimetallic nanocomposite nanocomposites were used to study the factors affecting the bimetal nanostructures and components as well as the catalytic properties of the nanocomposites with different bimetal structures. The main research content and the results obtained are as follows:
1, TiO2NW@ hollow Ag*/Pt nanocomposites: first, the silver nanoparticles (AgNP) were modified on the surface of the titanate nanowire (TiO2NW), and then a nano scale of platinum oxide (PtO) was coated on the surface of AgNP, that is, the TiO2NW@Ag*NP@PtO nanocomposite was successfully prepared. Ag*NP was used as a template to expand the silver from the silver nucleus to the shell and to make the reduction. The TiO2NW@ hollow Ag*/Pt nanocomposites were prepared. The effect of platinum source K2PtCl4 on the Ag*NP@PtO nanostructure and the indirect effect of the silver platinum ratio on the TiO2NW@ hollow Ag*/Pt nanocomposites were investigated. Meanwhile, the effects of the reaction time of Ag*NP@PtO and H2O2 on the structure of TiO2NW@ hollow Ag*/PtOx and TiO2NW@ hollow core Ag*/Pt nanocomposites were investigated. The results show that the control of the PtO thickness of the Ag*NP@PtO nanostructures can be controlled by the addition of the platinum source and the silver platinum ratio of the TiO2NW@ hollow Ag*/Pt nanocomposites can be indirectly controlled by the addition of the platinum source, and the controllable preparation of the hollow Ag*/Pt nanostructures can be realized by changing the reaction time of Ag*NP@PtO and H2O2. The hydrogenation reduction experiments of over catalyzed p-nitrophenol (4-NP) show that the conversion rate of 4-NP hydrogenated reduction decreases with the increase of the thickness of the Pt shell of the TiO2NW@Ag*NP@Pt nanocomposites, which is due to the decrease of the silver exposure and the reduction of the bimetallic interface. With the reaction of TiO2NW@Ag*NP@PtO nanocomposites with H2O2 The catalytic activity of 4-NP decreases as it increases first, which is due to the expansion of the silver nanoparticles and the change in the catalytic site of platinum and the entry of the bimetallic interface. Moreover, TiO2NW has a one-dimensional structure and different water solubility with the bimetallic nanomaterials, which is beneficial to the catalytic performance and the reusable rate. The improvement of.TiO2NW@ hollow Ag*/Pt nanocomposites has excellent catalytic performance. At the same time, the repeated cyclic catalysis of 4-NP experiments also proved that the nanocomposites have good reproducibility.
2, TiO2NW@ hollow Ag/AgPt nanocomposites: first, the upper AgNP is modified on the TiO2NW surface, and then the TiO2NW@ hollow Ag/AgPt nanocomposites are successfully prepared by the replacement reaction of H2PtCl6 and AgNP and the co reduction reaction of ascorbic acid. The hollow Ag/AgPt nanostructures and hollow structures of different concentration H2PtCl6 pairs are discussed. The effect of the surface structure and the proportion of AgPt alloy shows that the controlled concentration of H2PtCl6 can realize the controllable preparation of hollow Ag/AgPt nanostructures with different AgPt alloys and different structures. Through the hydrogenation reduction experiments of catalytic p-nitrophenol (4-NP), the hollow structure of TiO2NW@ hollow Ag/AgPt nanocomposites is demonstrated. It has excellent catalytic performance, which is due to the large specific surface area, the AgPt bimetallic interface and the different water solubility of TiO2NW. At the same time, through many cyclic catalytic 4-NP experiments, it shows that the hollow Ag/AgPt nanocomposites with hollow structure have excellent reproducibility. This is due to the fact that TiO2NW has a one-dimensional nanostructure.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O643.36
本文编号：2152945
[Abstract]:Bimetal nanomaterials are made up of two different metallic elements. Compared with single metal, bimetallic nanomaterials are not simple metal properties, but will derive more excellent properties. At the same time, due to the adjustable structure and composition of bimetal nanomaterials, as well as special physical and chemical properties, the nanomaterials endow the nanoscale. Materials are widely used in fuel cells, biological diagnosis, surface Raman enhancement and catalysts. Therefore, how to prepare structural adjustable bimetal nanomaterials is of great significance for the performance improvement of bimetallic nanomaterials. This paper has successfully prepared different structures on the surface modification of titanate nanowires. The Ag/Pt bimetallic nanocomposite nanocomposites were used to study the factors affecting the bimetal nanostructures and components as well as the catalytic properties of the nanocomposites with different bimetal structures. The main research content and the results obtained are as follows:
1, TiO2NW@ hollow Ag*/Pt nanocomposites: first, the silver nanoparticles (AgNP) were modified on the surface of the titanate nanowire (TiO2NW), and then a nano scale of platinum oxide (PtO) was coated on the surface of AgNP, that is, the TiO2NW@Ag*NP@PtO nanocomposite was successfully prepared. Ag*NP was used as a template to expand the silver from the silver nucleus to the shell and to make the reduction. The TiO2NW@ hollow Ag*/Pt nanocomposites were prepared. The effect of platinum source K2PtCl4 on the Ag*NP@PtO nanostructure and the indirect effect of the silver platinum ratio on the TiO2NW@ hollow Ag*/Pt nanocomposites were investigated. Meanwhile, the effects of the reaction time of Ag*NP@PtO and H2O2 on the structure of TiO2NW@ hollow Ag*/PtOx and TiO2NW@ hollow core Ag*/Pt nanocomposites were investigated. The results show that the control of the PtO thickness of the Ag*NP@PtO nanostructures can be controlled by the addition of the platinum source and the silver platinum ratio of the TiO2NW@ hollow Ag*/Pt nanocomposites can be indirectly controlled by the addition of the platinum source, and the controllable preparation of the hollow Ag*/Pt nanostructures can be realized by changing the reaction time of Ag*NP@PtO and H2O2. The hydrogenation reduction experiments of over catalyzed p-nitrophenol (4-NP) show that the conversion rate of 4-NP hydrogenated reduction decreases with the increase of the thickness of the Pt shell of the TiO2NW@Ag*NP@Pt nanocomposites, which is due to the decrease of the silver exposure and the reduction of the bimetallic interface. With the reaction of TiO2NW@Ag*NP@PtO nanocomposites with H2O2 The catalytic activity of 4-NP decreases as it increases first, which is due to the expansion of the silver nanoparticles and the change in the catalytic site of platinum and the entry of the bimetallic interface. Moreover, TiO2NW has a one-dimensional structure and different water solubility with the bimetallic nanomaterials, which is beneficial to the catalytic performance and the reusable rate. The improvement of.TiO2NW@ hollow Ag*/Pt nanocomposites has excellent catalytic performance. At the same time, the repeated cyclic catalysis of 4-NP experiments also proved that the nanocomposites have good reproducibility.
2, TiO2NW@ hollow Ag/AgPt nanocomposites: first, the upper AgNP is modified on the TiO2NW surface, and then the TiO2NW@ hollow Ag/AgPt nanocomposites are successfully prepared by the replacement reaction of H2PtCl6 and AgNP and the co reduction reaction of ascorbic acid. The hollow Ag/AgPt nanostructures and hollow structures of different concentration H2PtCl6 pairs are discussed. The effect of the surface structure and the proportion of AgPt alloy shows that the controlled concentration of H2PtCl6 can realize the controllable preparation of hollow Ag/AgPt nanostructures with different AgPt alloys and different structures. Through the hydrogenation reduction experiments of catalytic p-nitrophenol (4-NP), the hollow structure of TiO2NW@ hollow Ag/AgPt nanocomposites is demonstrated. It has excellent catalytic performance, which is due to the large specific surface area, the AgPt bimetallic interface and the different water solubility of TiO2NW. At the same time, through many cyclic catalytic 4-NP experiments, it shows that the hollow Ag/AgPt nanocomposites with hollow structure have excellent reproducibility. This is due to the fact that TiO2NW has a one-dimensional nanostructure.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O643.36
【参考文献】
相关期刊论文 前1条
1 陈旭红;王佳;;Au修饰Pt纳米双金属催化剂的制备及其催化活性研究[J];江苏技术师范学院学报(自然科学版);2008年01期
本文编号：2152945
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