本文選題：燃料電池　切入點：合金催化劑　出處：《信陽師范學(xué)院》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：Pt、Pd因?qū)状嫉扔袡C小分子有很好的電催化氧化能力,是目前廣泛使用的燃料電池催化劑。但由于Pt、Pd資源稀少、價格昂貴,阻礙了燃料電池的商業(yè)化發(fā)展。并且Pt在電催化氧化過程中極易被CO中間產(chǎn)物毒化,從而降低催化活性。因此,開發(fā)低Pt、Pd負載量的燃料電池催化劑,提高催化劑的催化活性和抗中毒能力,在推動燃料電池商業(yè)化方面顯得尤為重要。本論文從降低貴金屬用量、增大催化劑比表面積入手,制備了一系列具有特殊形貌的多孔Pt、Pd基合金催化劑。通過SEM、TEM、物理吸附儀等儀器,對所制備材料進行結(jié)構(gòu)表征,通過電化學(xué)測試,分析所制備催化劑對甲醇、甲酸的電催化性能,并取得了以下研究成果:1、在無表面活性劑的情況下,合成了高度均一,且粒徑大小約為500 nm的鋸齒狀多枝Pd3Cu納米合金催化劑,由XPS、XRD、EDS等分析手段得出,Pd、Cu兩種元素比例為3:1。其性能較商業(yè)鈀黑相比,具有相當(dāng)好的催化性能和穩(wěn)定性。2、通過水熱法,利用乙二醇對前驅(qū)體進行還原,改變前驅(qū)體Na2PdCl4、CuCl2·2H2O用量,制備出不同比例,具有3D網(wǎng)狀結(jié)構(gòu)的Pd-Cu合金催化劑。利用物理吸附儀對合金比表面積分析,得出Pd51Cu49和Pd76Cu24的比表面積分別為20.7m2·g-1和10.4 m2·g-1。電化學(xué)測試顯示Pd51Cu49具有更大的電化學(xué)活性面積。較鈀黑相比,對甲酸的電催化性能更優(yōu)。3、利用嵌段共聚物P123作為結(jié)構(gòu)導(dǎo)向劑,合成了具有多孔結(jié)構(gòu)的球形網(wǎng)狀Pt PdCu合金,比表面高達86.9 m2·g-1。此材料不僅包含了多孔結(jié)構(gòu)在電化學(xué)催化過程中具有的高傳質(zhì)能力和氣體滲透率,而且也彌補了傳統(tǒng)多孔結(jié)構(gòu)較長的物質(zhì)和離子傳輸距離,大大降低了過電位,使電極表面動力學(xué)反應(yīng)更好的進行。4、為進一步降低貴金屬用量,減少催化劑制作成本。我們又制備了具有多孔結(jié)構(gòu)的PtSnCu合金催化劑。Sn的加入可以在催化劑表面產(chǎn)生吸附態(tài)的OH,從而使CO2的轉(zhuǎn)化效率提高。并且,Cu隨電化學(xué)測試圈數(shù)的增加,可逐漸溶出,形成富Pt的催化表面,暴露更多的催化活性位點,顯著增強催化劑催化性能。是很具前景的合金催化劑。
[Abstract]:PTN PD is widely used as a fuel cell catalyst for its excellent electrocatalytic oxidation ability to small organic molecules such as methanol, but it is expensive because of its scarce resources. This hinders the commercial development of fuel cells, and Pt is easily poisoned by CO intermediates during electrocatalytic oxidation, which reduces the catalytic activity. Therefore, low PtPd supported fuel cell catalysts are developed. It is very important to promote the commercialization of fuel cell by improving the catalytic activity and anti-poisoning ability of the catalyst. In this paper, we start with reducing the amount of noble metal and increasing the specific surface area of the catalyst. A series of porous PtPd-based alloy catalysts with special morphology were prepared. The structure of the prepared materials was characterized by means of SEMMOTEM and physical adsorption apparatus. The electrocatalytic properties of the catalysts for methanol and formic acid were analyzed by electrochemical tests. The following research results were obtained: 1. In the absence of surfactants, the sawtooth multi-branched Pd3Cu nanocrystalline catalysts with high homogeneity and size of about 500nm were synthesized. The ratio of two elements of PdCU and Cu was found to be 3: 1 by means of XPSN XRDX EDS. Compared with commercial palladium black, its catalytic performance and stability were better. By hydrothermal method, the precursor was reduced by ethylene glycol, and the amount of Na2PdCl4CuCl2 路2H2O was changed, and the content of the precursor Na2PdCl4CuCl2 路2H2O was changed by hydrothermal method. Pd-Cu alloy catalysts with different proportions and 3D mesh structure were prepared. The specific surface area of the alloy was analyzed by physical adsorption apparatus. The specific surface areas of Pd51Cu49 and Pd76Cu24 were 20.7 m2 路g-1 and 10.4 m2 路g-1.Electrochemical tests showed that Pd51Cu49 had a larger electrochemical active area. Compared with palladium black, the electrocatalytic activity of Pd51Cu49 was better than that of palladium black. The block copolymer P123 was used as structural guide. Spherical reticulated Pt PdCu alloy with porous structure was synthesized, with a specific surface of 86.9 m2 路g-1.This material not only contains the high mass transfer capacity and gas permeability of porous structure in electrochemical catalytic process. It also makes up for the longer material and ion transport distance of the traditional porous structure, greatly reduces the overpotential, and makes the kinetic reaction on the electrode surface better. 4, in order to further reduce the amount of precious metals, In addition, the addition of PtSnCu alloy catalyst with porous structure can produce adsorptive OHs on the surface of the catalyst, thus increasing the conversion efficiency of CO2, and the Cu content increases with the increase of the number of electrochemical test cycles. It can be dissolved gradually to form Pt rich catalyst surface, expose more catalytic activity sites, and significantly enhance the catalytic performance of the catalyst. It is a promising alloy catalyst.
【學(xué)位授予單位】：信陽師范學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O643.36;TM911.4

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