纳米多孔Pd基燃料电池催化剂乙醇氧化反应及氧气还原反应催化性能研究

发布时间：2018-05-31 04:17

  本文选题：钯 + 乙醇　； 参考：《中国矿业大学》2017年硕士论文

【摘要】：直接醇类燃料电池(DEFC)因其具有高的功率密度,燃料存储安全方便,以及环境友好等优点,受到了研究者的广泛关注和研究。DEFC在投入到商业化生产中,仍面临挑战,如电极动力学慢,有机小分子等材料能量密度低,容易引起催化剂中毒等。为降低燃料电池成本、提高催化剂利用效率,Pd基催化剂的研究受到重视。本文采用熔体快淬结合去合金化法制备了纳米多孔PdM(NP-PdM)催化剂,其中M为Mn,Y,Ce,Ta,Nb,通过X射线粉末衍射(XRD),X射线光电子能谱分析(XPS),扫描电子显微镜(SEM),能量散射光谱(EDS),透射电子显微镜(TEM)对材料进行表征,并研究了其在碱性条件下对乙醇氧化反应(EOR)和氧还原(ORR)的电催化活性。主要研究内容和结论如下:采用电弧熔炼和熔体快淬的方法制备了Pd_(15)Mn_5Al_(80)、Pd_(15)Y_5Al_(80)、Pd_(15)Ce_5Al_(80)、Pd_(15)Ta_5Al_(80)和Pd_(15)Nb_5Al_(80)合金条带,用去合金化的方法制备出NP-PdMn、NP-PdY、NP-PdCe、NP-PdTa、NP-PdNb催化剂,并用XRD、XPS、SEM和TEM等测试方法对其结构、形貌及组成进行了分析。结果表明制备的催化剂具有纳米多孔结构,孔径约为5到10 nm左右。M金属的加入使得催化剂的EOR催化活性得到了显著提高,结果显示:NP-PdMn(64.9 m2/g)、NP-PdY(34.8m2/g)、NP-PdCe(32.7 m2/g)、NP-PdTa(489.8 m2/g)、NP-PdNb(153.3 m2/g)催化剂的电化学活性面积分别约为商业Pd/C(11.7 m2/g)的5.5倍、3.0倍、2.9倍、41.8倍和13.1倍。加入乙醇后的峰值电流密度分别为760.0 mAmg-1、1420.0mAmg-1、1045.1 m Amg-1、1901.8 mAmg-1、587.9 mAmg-1,约为商业Pd/C(400.0mAmg-1)的1.9倍、3.6倍、2.6倍、4.8倍和1.5倍。起峰电位分别移动了230 mV、190 mV、120 mV、270 mV和170 mV。在EOR稳定性测试结果显示,NP-PdMn、NP-PdY、NP-PdCe、NP-PdTa、NP-PdNb催化剂的稳定性优于商业Pd/C催化剂。在对NP-PdCe、NP-PdTa、NP-PdNb催化剂的ORR催化性能测试结果显示:三种催化剂与商业Pd/C催化剂的半波电位分别移动了53 m V、44 mV和44 mV,同时在电位为0.875 V时的质量活性分别约为商业Pd/C催化剂的3.5倍、3.5倍和3.1倍。通过NP-PdCe、NP-PdTa、NP-PdNb催化剂循环5000圈测试后,半波电位分别移动了10 mV、1 mV和19 mV,表现出良好的稳定性。这使得NP-PdMn、NP-PdY、NP-PdCe、NP-PdTa、NP-PdNb催化剂成为优于商业Pd/C的直接醇类燃料电池阳极和阴极催化剂。
[Abstract]:Because of its advantages of high power density, convenient fuel storage, and environmental friendliness, direct alcohol fuel cell (DEFC) has been widely concerned and studied by researchers. DEFC is still facing challenges in commercial production, because of its advantages such as high power density, convenient fuel storage, and environmental friendliness. For example, the electrode dynamics is slow and the energy density of organic small molecules is low, which can easily lead to catalyst poisoning and so on. In order to reduce the cost of fuel cell and improve the utilization efficiency of catalyst, the research of PD based catalyst has been paid more attention. In this paper, nano-porous PdMN NP-PdM) catalysts were prepared by melt rapid quenching and dealloying. Among them, M is Mn-YYC CeTaNb. The materials were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy scattering spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activities of EOR and ORR for ethanol oxidation under alkaline conditions were studied. 涓昏�佺爺绌跺唴瀹瑰拰缁撹�哄�備福�

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