本文關(guān)鍵詞： 燃料電池 氧還原反應(yīng) 吲哚 吲哚羧酸 親電中心 親核中心　出處：《浙江大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：燃料電池由于其能量轉(zhuǎn)換率高和對環(huán)境友好等優(yōu)點(diǎn)而受到廣泛關(guān)注。陰極氧還原反應(yīng)(ORR)是制約燃料電池發(fā)展和推廣的重要因素,傳統(tǒng)的ORR催化劑使用的是碳擔(dān)載鉑(Pt/C), Pt具有優(yōu)良的ORR催化活性,但是Pt是貴金屬,資源稀少,價格昂貴,限制了燃料電池的產(chǎn)業(yè)化發(fā)展,因此開發(fā)非貴金屬催化劑成為了燃料電池的研究熱點(diǎn)之一。本文研究了吲哚和吲哚羧酸修飾碳載非貴金屬材料作為ORR催化劑,探討其在酸性和堿性介質(zhì)中的催化機(jī)理,測試其電化學(xué)性能,并用于燃料電池,對其性能和穩(wěn)定性進(jìn)行驗(yàn)證。本文采用水熱法合成復(fù)合催化劑材料M-N/C,并首次采用原位透射電鏡對催化劑熱處理過程中的形貌和結(jié)構(gòu)變化進(jìn)行分析,采用傅里葉紅外光譜(FT-IR)、X射線粉末衍射儀(XRD)、核磁共振光譜(NMR)、電感耦合等離子體發(fā)射光譜(ICP)等分析方法對材料進(jìn)行分析表征；采用循環(huán)伏安法(CV)、旋轉(zhuǎn)圓盤法(RDE)等對材料的電化學(xué)性能進(jìn)行測試。通過對催化劑材料的結(jié)構(gòu)成分和在不同介質(zhì)中的電化學(xué)性能進(jìn)行分析,推測影響催化劑活性的關(guān)鍵因素。研究表明,吲哚修飾碳載鈷催化劑(Co-indole/BP)和吲哚羧酸(吲哚甲酸：ICA,吲哚乙酸：IAA,吲哚丙酸：IPA,吲哚丁酸：IBA)修飾碳載鈷催化劑都具有良好的ORR催化活性。Co-IAA/BP在酸性和堿性介質(zhì)中的的催化劑活性明顯高于Co-indole/BP。通過原位透射電鏡檢測到Co-indole/BP 和 Co-IAA/BP在氬氣環(huán)境下熱處理到900℃的過程中(將熱處理后的催化劑分別記作Co-indole/BP (900) 和 Co-IAA/BP (900)),有CO3O4晶體形成,Co-indole/BP (900)和Co-IAA/BP (900)在酸性和堿性介質(zhì)中均具有更高的ORR催化活性。此外,Co-IAA/BP (900)的氧還原初始電位、動力學(xué)電流密度和反應(yīng)轉(zhuǎn)換電子數(shù)都明顯高于Co-indole/BP (900)。Co-IAA/BP及Co-indole/BP (900) 和 Co-IAA/BP (900)催化劑在酸性介質(zhì)下也具有良好的ORR催化活性,是因?yàn)樵贑o-IAA和CO3O4中的氧原子具有孤對電子,能夠吸引酸性介質(zhì)中的質(zhì)子。在酸性介質(zhì)中,同時含有親電中心(CO3O4中的Co)和親核中心(CO3O4中的O)催化活性中心是其具有良好的ORR催化活性的主要原因。在以上研究成果的基礎(chǔ)上,通過直接甲醇燃料燃料電池(DMFC)和直接硼氫化鈉燃料電池(DBFC)對Co-IAA/BP (900)催化劑進(jìn)行了實(shí)證,在DMFC中,其放電性能比10%Pt/C要差,但是在DBFC中,其放電性能超過了10%Pt/C,說明Co-IAA/BP (900)可以替代10%Pt/C用于直接硼氫化鈉燃料電池中。通過陰極壽命測試表明的熱處理后的Co-indole/BP 和 Co-IAA/BP都具有良好的穩(wěn)定性。
[Abstract]:Fuel cells have attracted wide attention due to their high energy conversion rate and environmental friendliness. The cathode oxygen reduction reaction (ORR) is an important factor restricting the development and promotion of fuel cells. The traditional ORR catalyst is supported by carbon supported platinum (Pt / C), Pt has excellent catalytic activity for ORR, but Pt is precious metal, which is rare in resources and expensive in price, which limits the development of fuel cell industrialization. Therefore, the development of non-noble metal catalysts has become one of the research hotspots in fuel cells. In this paper, indole-and indole carboxylic acid-modified carbon-supported non-noble metal materials were studied as ORR catalysts, and their catalytic mechanism in acidic and alkaline media was discussed. Test its electrochemical performance and use it in fuel cells, In this paper, the composite catalyst material M-N / C was synthesized by hydrothermal method, and the morphology and structure of the catalyst during heat treatment were analyzed by in situ transmission electron microscope (TEM) for the first time. The materials were characterized by FT-IR X-ray powder diffractometer, nuclear magnetic resonance spectroscopy (NMR) and inductively coupled plasma emission spectrometry (ICP). The electrochemical properties of the catalysts were tested by cyclic voltammetry (CV) and rotating disk method (RDEs). The structure and the electrochemical properties of the catalyst materials in different media were analyzed. The key factors affecting the activity of the catalyst were speculated. Indole-modified carbon-supported cobalt catalysts Co-indole-a-bp and indole carboxylic acid (ICA: ICA, indole acetic acid: IAA, indole propionic acid: IPA, indole butyric acid: IBA) all have good ORR catalytic activity. The activity of Co-indole/BP and Co-IAA/BP was obviously higher than that of Co-indole / BP.The results of in situ transmission electron microscopy (TEM) showed that Co-indole/BP and Co-IAA/BP were heat-treated to 900 鈩，

本文編號：1548920