【摘要】：納米材料因其所具備獨特的物理性能、化學性能,一直備受廣大科研工作者的青睞。到目前為止,關(guān)于納米材料的研究已經(jīng)取得豐碩的成果,納米材料已經(jīng)被廣泛的應(yīng)用到光學傳感元件、仿生學、催化以及藥物化學等領(lǐng)域。隨著近年來對燃料電池研究的興起,催化劑作為影響燃料電池性能和大規(guī)模應(yīng)用的關(guān)鍵因素之一成為了人們關(guān)注的焦點。貴金屬鉑由于具有其他材料所不具備的高催化活性,常被選做反應(yīng)催化劑材料。但是貴金屬鉑催化劑同樣有著明顯的缺點,即昂貴的成本以及容易發(fā)生碳中毒現(xiàn)象。本文通過模板法成功制備得到了納米Pt-Ru合金催化劑、納米Pt-Ni合金催化劑以及Pt-Ru合金納米線催化劑三種材料,分別對三種材料進行性能測試發(fā)現(xiàn),相比較于目前商業(yè)化使用的鉑黑催化劑,本中得到的三種材料具有更高的電催化活性、更強的抗碳中毒能力以及更低的成本,主要工作如下：通過使用表面活性劑P123作為軟模板,抗壞血酸(AA)還原制備得到了納米Pt-Ru合金催化劑。通過電化學催化實驗研究發(fā)現(xiàn),由于堆積成球型結(jié)構(gòu)的催化劑顆粒大小在3nm左右且催化劑表面具有介孔結(jié)構(gòu),所以相比較于商業(yè)鉑黑催化劑具有更大的電催化活性表面積(ECSA);同時由于引入金屬Ru與Pt形成了合金結(jié)構(gòu),從而增加了催化劑抗碳中毒的能力,并且因為價格較低的Ru的引入,使得催化劑材料的成本相對于由純鉑構(gòu)成的商業(yè)鉑黑催化劑而言有所下降。通過選用非離子表面活性劑Brij58作為軟模板,利用硼氫化鈉在冰浴中還原,成功制備得到了不同含Pt質(zhì)量分數(shù)的納米Pt-Ni合金催化劑材料。制備得到的合金催化劑顆粒大小在6-8nm的范圍,顆粒分布均勻尺寸均一。通過電化學催化實驗研究發(fā)現(xiàn),六種不同質(zhì)量分數(shù)的電催化活性面積均明顯高于商業(yè)鉑黑催化劑,同時由于引入了金屬材料Ni使得催化劑抗碳中毒的能力得到了增強,并且因為Ni低廉的價格,大大降低了催化劑的成本。同時通過對比六種不同含量的催化劑材料性能發(fā)現(xiàn)Pt wt%=50%的樣品具有最高的電催化活性表面積42.9 m2 g-1,在催化甲醇氧化實驗中具有最大的正向掃描峰位電流密度(ECSA標準化后)0.84mA cm-2,較高的正反向掃描峰位電流密度比If/Ib=1.19。通過改進的Stober法制備了粒徑為30nm的二氧化硅小球,并使用抽濾法將二氧化硅小球填充到孔徑為200nm的多孔氧化鋁模板中,以此復合結(jié)構(gòu)為模板制備得到了三種不同含鉑質(zhì)量分數(shù)的Pt-Ru合金納米線材料。合成的合金納米線直徑200nm,且均勻分布有大量直徑為30nm的孔結(jié)構(gòu)。通過電催化實驗發(fā)現(xiàn),三種樣品的ECSA均大于商業(yè)鉑黑催化劑,且具有更強的抗碳中毒能力以及更低的成本。三種樣品中,Pt wt%=75%的樣品具有最高的ECSA=38.3 m2 g-1,最大的正向掃描峰位電流密度(ECSA標準化后)0.52 mA cm-2以及高的正反向掃描峰位電流密度比If/Ib=1.57。
[Abstract]:Nanomaterials are favored by researchers for their unique physical and chemical properties. Up to now, great achievements have been made in the research of nanomaterials. Nanomaterials have been widely used in the fields of optical sensing elements, bionics, catalysis and pharmaceutical chemistry. With the development of fuel cell research in recent years, catalyst as one of the key factors affecting fuel cell performance and large-scale application has become the focus of attention. Precious metal platinum is often selected as a catalyst for reaction because of its high catalytic activity that other materials do not. However, precious metal platinum catalysts also have obvious disadvantages, such as high cost and carbon poisoning. In this paper, three kinds of nanocrystalline Pt-Ru alloy catalysts, nanometer Pt-Ni alloy catalysts and Pt-Ru alloy nanowire catalysts were successfully prepared by template method. Compared with the current commercial use of platinum black catalysts, the three materials obtained in this paper have higher electrocatalytic activity, stronger resistance to carbon poisoning and lower cost. The main work is as follows: nanometer Pt-Ru alloy catalyst was prepared by using surfactant P123 as soft template and ascorbic acid (AA) reduced. By electrochemical catalytic experiments, it was found that the size of the catalyst was about 3nm and the mesoporous structure was found on the surface of the catalyst. Therefore, compared with commercial platinum black catalysts, the electrocatalytic surface area of (ECSA); is larger than that of commercial platinum black catalysts, and the metal Ru and Pt are introduced to form alloy structure, which increases the ability of the catalyst to resist carbon poisoning, and because of the introduction of lower price Ru, The cost of catalyst material is lower than that of commercial platinum black catalyst composed of pure platinum. Nonionic surfactant Brij58 was used as soft template and sodium borohydride was used to deoxidize in ice bath. Nanocrystalline Pt-Ni alloy materials with different mass fraction of Pt were prepared successfully. The particle size of the prepared alloy catalyst is in the range of 6-8nm, and the particle size is uniform. The electrochemical catalytic experiments showed that the electrocatalytic activity area of the six different mass fractions of the catalysts was significantly higher than that of commercial platinum black catalysts, and the ability of the catalysts to resist carbon poisoning was enhanced by the introduction of metal material Ni. And because of the low price of Ni, the cost of catalyst is greatly reduced. At the same time, by comparing the performance of six kinds of catalyst materials with different contents, it was found that the Pt wt%=50% sample had the highest electrocatalytic activity surface area of 42.9 m2 g-1, and the largest forward scanning peak current density (ECSA) in the catalytic methanol oxidation experiment. Higher peak current density ratio of positive and backward scanning of 0.84mA cm-2, to If/Ib=1.19. Silica pellets with diameter of 30nm were prepared by improved Stober method and filled into porous alumina template with pore diameter of 200nm by filter method. Three kinds of Pt-Ru alloy nanowires with different platinum content were prepared by using the composite structure as template. The synthesized nanowires are 200 nm in diameter and have a large number of pore structures with 30nm diameter uniformly distributed. The results of electrocatalytic experiments showed that the ECSA of the three samples was higher than that of commercial platinum black catalysts and had stronger resistance to carbon poisoning and lower cost. Of the three kinds of samples, the sample of Pt wt%=75% has the highest ECSA=38.3 m2 g-1, the maximum peak current density of positive scan (after ECSA standardization) of 0.52 mA cm-2, and the high peak current density ratio of positive and negative scanning to If/Ib=1.57..
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：O643.36;TB383.1

【共引文獻】

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2 李嬌;Mg/Zn摻雜孔雀石和Al/Zr摻雜綠銅鋅礦性質(zhì)的第一性原理研究[D];太原理工大學;2015年

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本文編號：2265461