【摘要】：雙金屬納米材料由兩種不同金屬元素構成，與單金屬材料相比，雙金屬納米材料不是簡單的金屬性能相加，而是會衍生出更多的優(yōu)異性能。同時，由于雙金屬納米材料的結構和成分可調，以及特殊的物理化學性質，從而賦予了這種納米材料在燃料電池、生物診斷、表面拉曼增強以及催化劑等方面的廣泛的應用前景。因此，如何制備結構可調控的雙金屬納米材料，對于雙金屬納米材料的性能改善具有很重大的意義。本論文成功地制備出在鈦酸鹽納米線表面修飾不同結構的Ag/Pt雙金屬納米結構的納米復合材料，研究了影響其雙金屬納米結構以及組分的因素以及不同雙金屬結構的納米復合材料的催化性能。主要的研究內容以及取得的成果如下： 1、TiO2NW@空心Ag*/Pt納米復合材料：首先，將銀納米顆粒（AgNP）修飾在鈦酸鹽納米線（TiO2NW）表面，然后在AgNP表面上包覆一層納米級的一氧化鉑（PtO），即成功的制備出TiO2NW@Ag*NP@PtO納米復合材料。以Ag*NP為模板，將銀從銀核外擴到殼層以及還原，制備出TiO2NW@空心Ag*/Pt納米復合材料。探討鉑源K2PtCl4對Ag*NP@PtO納米結構的影響，以及TiO2NW@空心Ag*/Pt納米復合材料的銀鉑比的間接影響。同時，探討了Ag*NP@PtO與H2O2反應時間對TiO2NW@空心Ag*/PtOx及TiO2NW@空心Ag*/Pt納米復合材料的結構影響。PtOx可以通過NaBH4還原制備出單質鉑。結果表明，，改變鉑源的加入量可以實現(xiàn)對Ag*NP@PtO納米結構的PtO厚度的可控制備以及間接調控TiO2NW@空心Ag*/Pt納米復合材料的銀鉑比；改變Ag*NP@PtO與H2O2反應時間可以實現(xiàn)空心Ag*/Pt納米結構的可控制備。通過催化對硝基苯酚（4-NP）氫化還原實驗，表明隨著TiO2NW@Ag*NP@Pt納米復合材料的Pt殼層的厚度增加，催化4-NP氫化還原的轉化率反而降低，這是由于銀的裸露程度降低，使可進入雙金屬界面的減少。隨著TiO2NW@Ag*NP@PtO納米復合材料與H2O2反應時間的逐漸增加，催化4-NP活性隨著先增加后降低，這是由于銀納米顆粒的外擴，使鉑的催化位點以及可進入的雙金屬界面的發(fā)生改變。并且，TiO2NW具有一維的結構以及與雙金屬納米材料的不同水溶性，有利于催化性能以及可重復利用率的提高。TiO2NW@空心Ag*/Pt納米復合材料具有優(yōu)異的催化性能，同時對其多次循環(huán)催化4-NP實驗也證明其具有良好的可重復利用率。 2、TiO2NW@空心Ag/AgPt納米復合材料：首先，在TiO2NW表面上修飾上AgNP，然后通過鉑前驅體H2PtCl6與AgNP的置換反應以及抗壞血酸的共還原反應，成功地制備出TiO2NW@空心Ag/AgPt納米復合材料。探討了不同濃度H2PtCl6對空心Ag/AgPt納米結構、空心結構的表面結構以及AgPt合金比例的影響。結果表明，調控濃度H2PtCl6可實現(xiàn)具有不同AgPt合金比例以及修飾不同結構的空心Ag/AgPt納米結構的可控制備。通過催化對硝基苯酚（4-NP）氫化還原實驗，表明片狀空心結構TiO2NW@空心Ag/AgPt納米復合材料具有優(yōu)異的催化性能，這是由于片狀空心結構具有大的比表面積、具有可進入的AgPt雙金屬界面以及TiO2NW具有不同的水溶性。同時，通過多次循環(huán)催化4-NP實驗，表明片狀空心結構的TiO2NW@空心Ag/AgPt納米復合材料具有優(yōu)異的可重復利用率，這是由于TiO2NW具有一維納米結構。
[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.
【學位授予單位】：浙江理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O643.36

【參考文獻】

相關期刊論文 前1條

1 陳旭紅;王佳;;Au修飾Pt納米雙金屬催化劑的制備及其催化活性研究[J];江蘇技術師范學院學報(自然科學版);2008年01期

本文編號：2152945