本文關(guān)鍵詞： Pt基催化劑 Pd基催化劑 過渡金屬 甲醇 甲酸 電催化氧化　出處：《煙臺(tái)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：燃料電池是高效、綠色的發(fā)電裝置，其中直接甲醇燃料電池(DMFC)和直接甲酸燃料電池(DFAFC)被認(rèn)為是最有應(yīng)用前景的能源裝置。Pt電極是目前常用的DMFC陽極催化劑，在電化學(xué)方面顯示出良好的催化性能。但Pt資源有限，價(jià)格昂貴，且容易吸附CO而導(dǎo)致催化劑中毒，使用壽命縮短。對(duì)DFAFC，Pd基催化劑具有很好的電催化活性，但穩(wěn)定性也有待提高。 本論文在優(yōu)化制備條件的基礎(chǔ)上，通過添加Fe、Co、Ni等廉價(jià)過渡金屬制備了炭黑負(fù)載Pt-M及Pd-M雙金屬催化劑，采用X射線衍射(XRD)、透射電子顯微鏡(TEM)、X射線光電子能譜(XPS)等分析技術(shù)研究了所得催化劑的形貌、結(jié)構(gòu)及表面組成，以循環(huán)伏安法(CV)、計(jì)時(shí)電流法及CO吹掃循環(huán)伏安法分別考察了Pt基催化劑對(duì)甲醇、Pd基催化劑對(duì)甲酸的電催化活性、穩(wěn)定性及抗CO中毒性能。通過引入天然聚合物殼聚糖分子對(duì)炭黑載體進(jìn)行改性，制備了殼聚糖-炭黑復(fù)合物負(fù)載Pt及Pd催化劑，并考察了它們對(duì)甲醇、甲酸的電催化活性與穩(wěn)定性。將催化劑的結(jié)構(gòu)與其電催化性能進(jìn)行關(guān)聯(lián)，論文所得主要結(jié)果如下： 1.考察了溶液pH值、Pt負(fù)載量及Pt/Ni原子比等制備條件對(duì)Pt-Ni/C催化劑用于甲醇電催化氧化反應(yīng)的影響。結(jié)果表明：當(dāng)溶液pH為9，Pt負(fù)載量為5%，Pt/Ni原子比為1:1時(shí)所得催化劑具有最好的電催化活性與穩(wěn)定性。 2. Pt基雙金屬催化劑對(duì)甲醇的電催化氧化活性次序?yàn)椋篜t/CPt-Fe/CPt-Ni/CPt-Co/C。從幾何效應(yīng)講，，第二金屬的引入使Pt粒子更小、分散更均勻，從而增大了電化學(xué)活性面積，提高了Pt的利用率；從電子效應(yīng)看，第二金屬強(qiáng)的給電子效應(yīng)能使Pt2+濃度減少，Pt0表面百分濃度增加。其中以Co、Ni所表現(xiàn)出的兩種效應(yīng)最好，因此具有最好的催化活性及穩(wěn)定性。 3. Pd基雙金屬催化劑對(duì)甲酸的電催化氧化活性次序?yàn)椋篜d/C Pd-Fe/C Pd-Ni/C Pd-Co/C。第二金屬的添加可使催化劑顆粒變小、分散度提高。Pd基催化劑具有比Pt基催化劑更高的甲酸氧化活性。 4.殼聚糖可在一定程度上抑制金屬顆粒的聚集長大，提高金屬的分散度，從而改善Pt催化劑對(duì)甲醇、Pd催化劑對(duì)甲酸的電催化活性與穩(wěn)定性。
[Abstract]:Fuel cell is an efficient and green power generation device, in which direct methanol fuel cell (DMFC) and direct formic acid fuel cell (DFAFFC) are considered to be the most promising energy devices. Pt electrode is the commonly used anode catalyst for DMFC. However, Pt has limited resources, high price, easy to adsorb CO and lead to poisoning of catalyst and shorten its service life. It has good electrocatalytic activity for DFAFC- Pd-based catalyst. But stability also needs to be improved. On the basis of optimizing the preparation conditions, Pt-M and Pd-M bimetallic catalysts supported on carbon black were prepared by adding cheap transition metals, such as Feo Co-Ni, etc. The morphology, structure and surface composition of the catalyst were studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrocatalytic activity of Pt based catalyst for formic acid was investigated by cyclic voltammetry, chronoamperometric method and CO sweep cyclic voltammetry. By introducing natural polymer chitosan molecule to modify carbon black support, Pt and PD catalysts supported on chitosan / carbon black complex were prepared, and their effects on methanol were investigated. The electrocatalytic activity and stability of formic acid. The structure of the catalyst is correlated with its electrocatalytic activity. The main results obtained in this paper are as follows:. 1. The effects of preparation conditions such as pH value of solution, Pt loading and Pt/Ni atom ratio on the electrocatalytic oxidation of methanol over Pt-Ni/C catalyst were investigated. The results showed that the catalyst was prepared when the pH value of the solution was 5 and the Pt / Ni atom ratio was 1: 1. It has the best electrocatalytic activity and stability. 2. The order of electrocatalytic oxidation activity of Pt based bimetallic catalyst for methanol is: Pt / CPt-Fe / CPt-Ni / CPt-Co / C. From the geometry effect, the introduction of the second metal makes Pt particles smaller and more uniform, thus increasing the electrochemical active area and increasing the utilization rate of Pt; From the point of view of electron effect, the strong electron donating effect of the second metal can reduce the concentration of Pt2 and increase the surface concentration of Pt0. Among them, the two effects of Cot0 are the best, so they have the best catalytic activity and stability. 3. The electrocatalytic oxidation activity of PD based bimetallic catalyst for formic acid is in the order of: PD / C Pd-Fe/C Pd-Ni/C Pd-Co / C. the addition of the second metal can make the catalyst particle smaller, and the dispersion of the catalyst increases. The catalyst has higher formic acid oxidation activity than the Pt based catalyst. 4. Chitosan can inhibit the aggregation and growth of metal particles to a certain extent and improve the dispersion of metals, thus improving the electrocatalytic activity and stability of Pt catalysts for methanol and PD catalysts for formic acid.
【學(xué)位授予單位】：煙臺(tái)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TQ426;TM911.4

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