本文選題：燃料電池 + 化學(xué)還原法�。� 參考：《湖南科技大學(xué)》2015年碩士論文

【摘要】：燃料電池是能直接將化學(xué)能轉(zhuǎn)化成電能的發(fā)電裝置,是一種高效、環(huán)保的發(fā)電技術(shù),在當(dāng)今資源緊缺的背景下,具有重要研究意義。直接醇燃料電池分別以醇類和氧氣為燃料和氧化劑,具有燃料多樣、攜帶方便、易于儲存等特點。Pt作為燃料電池的催化劑因價格昂貴、易中毒等問題而受到限制,Pd的價格相對便宜,且在堿性溶液中對醇類氧化具有較高的電催化活性,因此,開發(fā)新型Pd基催化劑成為人們研究關(guān)注的重點。本文研究了PdSnNi、PdAg催化劑的制備,采用各種表征方法,觀察了催化劑的晶型結(jié)構(gòu)、表面形貌以及粒徑大小,并研究了催化劑對乙醇、丙醇和丁醇(簡稱C2-C4醇)氧化的活性和對氧還原反應(yīng)(ORR)的活性。以PdSnNi/MWCNT為陽極催化劑,組裝了無膜直接醇燃料電池,并測試了其放電性能。本論文研究的主要內(nèi)容包括以下幾個方面:(1)采用化學(xué)還原法,以酸化碳納米管為載體,硼氫化鈉為還原劑,制備了Pd/MWCNT、PdSn/MWCNT、PdNi/MWCNT、PdSnNi/MWCNT催化劑,采用TEM、XRD等表征方法對所制備的催化劑進行了表征,通過循環(huán)伏安、計時電流等電化學(xué)測試方法,在堿性環(huán)境中對C2-C4醇的氧化活性和穩(wěn)定性進行了測試。結(jié)果表明:PdSnNi/MWCNT催化劑對各類醇的氧化表現(xiàn)出最好的電催化活性,其中對乙醇最大氧化電流密度為83.2 mA·cm-2,對正丙醇的最大氧化電流密度為142.5mA·cm-2,對正丁醇的最大氧化電流密度為76.2mA·cm-2,且正丙醇和正丁醇的氧化效果分別好于其異構(gòu)體的氧化。(2)采用循環(huán)伏安、線性掃描等電化學(xué)測試方法研究了Pd/MWCNT、PdSn/MWCNT、PdNi/MWCNT、PdSnNi/MWCNT催化劑對氧還原反應(yīng)的活性。結(jié)果表明:無論在堿性還是酸性溶液中,PdNi/MWCNT催化劑表現(xiàn)出最佳的ORR活性,在堿性溶液中,PdNi/MWCNT的起始電位為-0.08V,在轉(zhuǎn)速為2000 rpm時,其極限擴散電流密度為3.51 mA·cm-2,在酸性溶液中,PdNi/MWCNT的起始電位為0.61V,在轉(zhuǎn)速為2000 rpm時,其極限擴散電流密度為4.44 mA·cm-2,表明PdNi/MWCNT是一種對ORR活性較好的催化劑,有望作為燃料電池的陰極材料。(3)采用化學(xué)還原法,以酸化碳納米管為載體,硼氫化鈉為還原劑,制備了Pd/MWCNT、Pd4Ag1/MWCNT、Pd2Ag1/MWCNT、Pd1Ag1/MWCNT催化劑,采用TEM、XRD等表征方法對所制備的催化劑進行了表征,通過循環(huán)伏安電化學(xué)測試方法,改變不同醇的濃度以及反復(fù)循環(huán)掃描次數(shù),在堿性環(huán)境中對C2-C4醇的氧化活性和穩(wěn)定性進行了測試,結(jié)果表明:Pd4Ag1/MWCNT催化劑對各類醇的氧化表現(xiàn)出最好的活性,其中對乙醇最大氧化電流密度為102.7 mA·cm-2,對正丙醇的最大氧化電流密度為162.7 mA·cm-2,對正丁醇的最大氧化電流密度為84.8mA·cm-2,且正丙醇和正丁醇的氧化效果分別好于其異構(gòu)體的氧化。(4)以PdSnNi/MWCNT催化劑為陽極材料,高溫?zé)峤夥ㄖ苽涞腇eCo/C-PANI催化劑為陰極材料,組裝了以空氣為燃料的無膜直接醇燃料電池,通過測試表明:以乙醇、正丙醇、異丙醇、正丁醇、異丁醇和仲丁醇為燃料時,燃料電池的開路電壓依次為0.68V、0.69V、0.61V、0.50V、0.51V、0.48V,其中正丙醇為燃料時,電池的電流功率密度最大,為0.51W g(Pd)-1。
[Abstract]:Fuel cell is a power generating device that can convert chemical energy into electric energy directly. It is an efficient and environmentally friendly power generation technology. It has important research significance in the background of resource shortage today. Direct alcohol fuel cells use alcohols and oxygen as fuel and oxidizing agent respectively, which have the characteristics of.Pt as fuel, easy to carry, easy to store and so on. The catalyst of the battery is limited because of the high price, easy poisoning and so on. The price of Pd is relatively cheap, and it has high electrocatalytic activity for alcohols oxidation in alkaline solution. Therefore, the development of new Pd based catalysts has become the focus of attention. The preparation of PdSnNi, PdAg catalyst is studied in this paper, and various characterization methods are used in this paper. The crystal structure, surface morphology and particle size of the catalyst were investigated, and the activity of the catalyst to ethanol, propanol and butanol (C2-C4 alcohol) oxidation and the activity of oxygen reduction reaction (ORR) were investigated. The film free direct alcohol fuel cell was assembled with PdSnNi/MWCNT as the anode catalyst and its discharge performance was tested. The main research in this paper was in this paper. The contents are as follows: (1) using chemical reduction method, using the acidified carbon nanotube as the carrier and the sodium borohydride as the reducing agent, Pd/MWCNT, PdSn/MWCNT, PdNi/MWCNT, PdSnNi/MWCNT catalyst are prepared, and the catalysts are characterized by TEM, XRD and so on. The electrochemical testing methods, such as cyclic voltammetry, timing current and so on, are used. The oxidation activity and stability of C2-C4 alcohol were tested in the alkaline environment. The results showed that the PdSnNi/MWCNT catalyst showed the best electrocatalytic activity for the oxidation of all kinds of alcohols. The maximum oxidation current density for ethanol was 83.2 mA. Cm-2, the maximum oxidation electric current density for n-propanol was 142.5mA. Cm-2, and the maximum oxygen of n-butanol was obtained. The current density is 76.2mA. Cm-2, and the oxidation effect of n-propanol and n-butanol is better than the oxidation of its isomers. (2) the activity of Pd/MWCNT, PdSn/MWCNT, PdNi/MWCNT, PdSnNi/MWCNT catalyst for oxygen reduction reaction is studied by cyclic voltammetry and linear scanning. The results show that the activity of the catalyst is in alkaline or acid solution. In the alkaline solution, the starting potential of PdNi/MWCNT is -0.08V. At the speed of 2000 rpm, the limiting diffusion current density is 3.51 mA. Cm-2. In the acid solution, the starting potential of PdNi/MWCNT is 0.61V, and the limit diffusion current density is 4.44 mA. At the speed of 2000 rpm, the initial diffusion current density is 4.44 mA. PdNi/MWCNT is a good catalyst for ORR activity, which is expected to be the cathode material for fuel cells. (3) chemical reduction method, acidified carbon nanotubes as the carrier, sodium borohydride as reducing agent, prepared Pd/MWCNT, Pd4Ag1/MWCNT, Pd2Ag1/MWCNT, Pd1Ag1/MWCNT catalyst, using TEM, XRD and other characterization methods for the preparation of the catalyst. By means of cyclic voltammetry, the oxidation activity and stability of C2-C4 alcohol are tested in alkaline environment by changing the concentration of different alcohols and the frequency of repeated cycle scanning. The results show that the Pd4Ag1/MWCNT catalyst shows the best activity for the oxidation of various alcohols, and the maximum oxidation current density for ethanol is the same. 102.7 mA. Cm-2, the maximum oxidation current density for n-propanol is 162.7 mA. Cm-2, the maximum oxidation current density of n-butanol is 84.8mA. Cm-2, and the oxidation effect of n-butanol and n-butanol is better than the oxidation of its isomers respectively. (4) the PdSnNi/MWCNT catalyst is the anode material and the FeCo/C-PANI catalyst prepared by high temperature pyrolysis is the cathode material. Material, a non film direct alcohol fuel cell with air as fuel is assembled. The test shows that the open circuit voltage of fuel cell is 0.68V, 0.69V, 0.61V, 0.50V, 0.51V, 0.48V when ethanol, n-propanol, isopropanol, isobutanol and SEC butanol are used as fuel, and the current power density of the battery is the largest when n-propyl alcohol is fuel, which is 0.51W G. (Pd) -1.

【學(xué)位授予單位】：湖南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O643.36;TB383.1

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相關(guān)期刊論文 前1條

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本文編號：1878707