石墨烯基燃料电池阴极催化剂的制备及氧还原性能研究
发布时间：2019-06-03 01:52
【摘要】：燃料电池因具有高的能量转换效率,较大的能量密度且较小的污染而日趋受到人们的关注。然而昂贵的成本致使燃料电池现在仍未批量生产,其中燃料电池阴极催化剂的成本占很大的比例。本文采用微波协助乙二醇法制备燃料电池阴极催化剂,以降低燃料电池成本为核心,重点对提高燃料电池的催化活性和稳定性进行了研究。 用改进的Hummers法制备了氧化石墨,采用常规干燥和低温冷冻干燥两种方式干燥样品。将常规干燥的氧化石墨高温膨胀得到膨胀后的氧化石墨,以膨胀后的氧化石墨为载体的前驱体,氯铂酸为铂源,分别研究了微波时间,溶剂比例,pH值对催化性能的影响。用X射线衍射仪(XRD),扫描电镜(SEM),透射电镜(TEM),傅里叶红外光谱(FT-IR),拉曼光谱(Raman),循环伏安曲线(CV),线性扫描曲线(LSV),时间电流曲线(i-t)等测试手段对催化剂进行了表征,结果表明以膨胀后的氧化石墨为载体的前驱体,氯铂酸的乙二醇溶液为铂源,掺杂30%的去离子水的乙二醇溶液为还原剂,在微波时间为50s-(30s)-60s-(40s)-60s,不加助分散剂的条件下制备出的Pt/graphene催化剂的颗粒分布均匀,平均粒径是2.4nm,电化学活性表面积大,铂的利用率提高,催化剂的电化学性能优异,半波电位为0.65V比商业催化剂的半波电位小0.01V,其电化学稳定性远高于商业催化剂的电化学稳定性。 为了降低铂的含量,以膨胀后的氧化石墨为载体的前驱体制备了铂镍原子总的质量分数为20%的Pt-Ni/graphene催化剂,比较了不同铂镍比例1(mass%)催化剂的电化学性能,研究发现铂镍原子比为3：1的铂镍催化剂(Pt3Ni/graphene-1)的电化学性能较其它比例的铂镍催化剂的电化学性能好。研究表明该催化剂是合金结构,晶面间距是0.223nm,石墨烯上负载的颗粒的平均粒径为2.7nm,合金颗粒分散均匀,该催化剂的半波电位是0.55V,比商业催化剂的半波电位小,但是电化学稳定性高于商业催化剂。此外,还以冷冻干燥后的氧化石墨为载体的前驱体制备了铂镍比例为3：1的Pt3Ni/graphene-2催化剂,通过XRD, SEM, TEM等物理表征和电化学性能表征发现,石墨烯上负载的粒子是合金颗粒,粒径大小约为3.7nm,该催化剂的半波电位为0.50V,比商业催化剂的半波电位小,但是比商业催化剂的电化学稳定性好。因此,石墨烯是燃料电池阴极催化剂的优良载体,用其作为载体不仅可以提高负载粒子的利用率,而且还具有很好的耐腐蚀性和电化学稳定性。
[Abstract]:Fuel cells have attracted more and more attention because of their high energy conversion efficiency, high energy density and low pollution. However, the high cost of fuel cell is still not mass production, in which the cost of fuel cell cathode catalyst accounts for a large proportion. In this paper, microwave assisted ethylene glycol method was used to prepare fuel cell cathode catalyst. In order to reduce the cost of fuel cell, the improvement of catalytic activity and stability of fuel cell was studied. Graphite oxide was prepared by improved Hummers method, and the samples were dried by conventional drying and low temperature freeze-drying. The expanded graphite oxide was obtained by expanding the conventional dry graphite oxide at high temperature. The effects of microwave time, solvent ratio and pH value on the catalytic performance were studied by using expanded graphite oxide as precursor and chloroplatinic acid as platinum source, respectively. X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier infrared spectroscopy (FT-IR) Raman spectrum (Raman), cyclic volt-ampere curve (CV), linear scanning curve (LSV), The catalyst was characterized by time current curve (I 鈮，
本文编号：2491578
[Abstract]:Fuel cells have attracted more and more attention because of their high energy conversion efficiency, high energy density and low pollution. However, the high cost of fuel cell is still not mass production, in which the cost of fuel cell cathode catalyst accounts for a large proportion. In this paper, microwave assisted ethylene glycol method was used to prepare fuel cell cathode catalyst. In order to reduce the cost of fuel cell, the improvement of catalytic activity and stability of fuel cell was studied. Graphite oxide was prepared by improved Hummers method, and the samples were dried by conventional drying and low temperature freeze-drying. The expanded graphite oxide was obtained by expanding the conventional dry graphite oxide at high temperature. The effects of microwave time, solvent ratio and pH value on the catalytic performance were studied by using expanded graphite oxide as precursor and chloroplatinic acid as platinum source, respectively. X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier infrared spectroscopy (FT-IR) Raman spectrum (Raman), cyclic volt-ampere curve (CV), linear scanning curve (LSV), The catalyst was characterized by time current curve (I 鈮，
本文编号：2491578
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