發(fā)布時間：2018-02-10 11:05

  本文關鍵詞： 鈀基納米催化劑 晶體生長 框架結構 納米片 異質(zhì)結構 氧還原反應二氧化碳電還原反應　出處：《中國科學技術大學》2017年碩士論文　論文類型：學位論文

【摘要】：貴金屬納米材料作為一類重要的催化劑,在很多催化反應中都有著廣泛的應用前景,例如,它們既可以被用于燃料電池中,也可以被用于CO2電還原反應以及光解水反應中。然而,貴金屬在地球上的儲量稀少,因此人們開始大力發(fā)展具有不同結構的催化劑,這樣不僅可以在一定程度上減少貴金屬的使用,并且往往還因為組分之間的協(xié)同效應而表現(xiàn)出更好的催化性能。對于貴金屬納米催化劑來說,它的催化性能與其尺寸、表面結構以及組分密切相關。因此,為了得到性能更優(yōu)越的催化劑,我們常常通過調(diào)節(jié)這些參數(shù)來改善催化劑的性能。對于鈀基納米催化劑來說,大的比表面積、高指數(shù)晶面暴露以及組分之間的協(xié)同效應均能有效提高催化劑的催化性能。然而在晶體的生長過程中,金屬納米材料趨向形成最小表面積和低表面能晶面。因此,如何獲得理想結構的催化劑也是相關研究的研究重點。本論文主要工作旨在合成一些鈀基納米材料,并運用動力學調(diào)控、晶種生長法等多種調(diào)控方法,精心設計合成了一些納米結構,例如,結構開放度較高的框架結構、具有協(xié)同效應的異質(zhì)結構。一方面,這些特殊結構的合成拓寬了催化劑的設計思路,另一方面,它們也在燃料電池、二氧化碳電還原等領域表現(xiàn)出了優(yōu)越的性能。本論文共有四章,各章節(jié)內(nèi)容簡述如下:在第一章中,我們簡單介紹了貴金屬納米材料的基本結構特征、性能影響因素、晶體生長理論以及合成現(xiàn)狀。其中,我們通過實例說明了幾個性能影響因素對貴金屬納米材料的催化性能的影響,以及如何根據(jù)這些影響因素設計一些對于催化反應有特殊貢獻的金屬納米晶體,或者根據(jù)一些特殊結構在催化領域的顯著性能來精心設計一些結構。在第二章中,我們首先介紹了框架結構在不同催化體系中的應用及其合成方法。然后我們通過動力學控制,在Pd八面體上選擇性沉積Pt原子并通過硝酸刻蝕的方法去除Pd晶核成功制備了結構高度開放的Pt-Pd雙金屬框架結構,詳細了分析了該框架結構的構造以及組成,并探索了該框架結構在燃料電池陰極氧還原反應中的電催化性能。在第三章中,我們首先介紹了 CO2電還原發(fā)展現(xiàn)狀及其催化劑發(fā)展現(xiàn)狀,然后我們通過模板誘導生長法成功合成了 Pd方形納米片-rGO異質(zhì)結構,詳細分析了該異質(zhì)結構中Pd方形納米片的晶體結構,并探究了該異質(zhì)結構在二氧化碳電還原方面的應用。在第四章中,我們展望了金屬納米材料應用前景,并從催化劑的合成、性能測試以及催化劑與性能之間的關系等多個方面闡述了貴金屬納米催化劑研究中存在的一些機遇和挑戰(zhàn)。
[Abstract]:As a kind of important catalyst, noble metal nanomaterials have been widely used in many catalytic reactions. For example, they can be used in fuel cells. They can also be used in CO2 electroreduction and photolysis reactions. However, precious metals are scarce on Earth, so people are beginning to develop catalysts with different structures. This not only reduces the use of precious metals to a certain extent, but also tends to exhibit better catalytic performance because of the synergistic effect between components. The surface structure and composition are closely related. Therefore, in order to obtain better catalysts, we often improve the performance of the catalysts by adjusting these parameters. For palladium based nanocatalysts, the specific surface area is large. The high exponent crystal plane exposure and the synergistic effect among the components can effectively improve the catalytic performance of the catalyst. However, in the process of crystal growth, the metal nanomaterials tend to form the minimum surface area and the low surface energy crystal surface. The main purpose of this thesis is to synthesize some palladium based nanomaterials, and to use the kinetic control, seed growth method and other control methods. Some nanostructures have been carefully designed and synthesized, such as frame structures with high structural openness and heterogeneity with synergistic effects. On the one hand, the synthesis of these special structures broadens the design ideas of catalysts, on the other hand, They also show excellent performance in the fields of fuel cell, carbon dioxide electroreduction and so on. In this paper, there are four chapters, and the contents of each chapter are summarized as follows: in the first chapter, we briefly introduce the basic structural characteristics of noble metal nanomaterials. Among them, we illustrate the effect of several performance factors on the catalytic performance of noble metal nanomaterials through examples. And how to design some metal nanocrystals that have a special contribution to the catalytic reaction based on these factors, or elaborate some structures according to the remarkable performance of some special structures in the catalytic field. We first introduced the application of the frame structure in different catalytic systems and its synthesis methods. Selective deposition of Pt atoms on PD octahedron and removal of PD nucleus by nitric acid etching were used to fabricate the highly open Pt-Pd bimetallic frame structure. The structure and composition of the frame structure were analyzed in detail. The electrocatalytic properties of the frame structure in the cathodic oxygen reduction reaction of fuel cells were explored. In chapter 3, we first introduced the development of CO2 electroreduction and the current development of catalysts. Then we successfully synthesized the PD square nanochip -rGO heterostructure by template-induced growth method, and analyzed the crystal structure of the PD square nano-chip in detail. The application of the heterostructure in the electroreduction of carbon dioxide is also discussed. In Chapter 4th, we look forward to the application of metal nanomaterials and the synthesis of catalysts. Some opportunities and challenges in the research of noble metal nanocatalysts were discussed from the aspects of performance test and the relationship between catalyst and performance.
【學位授予單位】：中國科學技術大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O643.36

【參考文獻】

相關期刊論文 前4條

1 Xue Wang;Aleksey Ruditskiy;Younan Xia;;Rational design and synthesis of noble-metal nanoframes for catalytic and photonic applications[J];National Science Review;2016年04期

2 張雷;金明尚;蔣亞琪;江智淵;匡勤;謝兆雄;;高指數(shù)晶面裸露的貴金屬納米晶體的合成[J];中國科學:化學;2012年11期

3 Rajender Gupta;Rachid B Slimane;Alan E Bland;Ian Wright;;Progress in carbon dioxide separation and capture: A review[J];Journal of Environmental Sciences;2008年01期

4 孫世剛;原子和分子水平層次的表面電化學與電催化研究[J];電化學;1998年01期

，

本文編號：1500371