【摘要】：燃料電池因具有高的能量轉(zhuǎn)換效率,較大的能量密度且較小的污染而日趨受到人們的關(guān)注。然而昂貴的成本致使燃料電池現(xiàn)在仍未批量生產(chǎn),其中燃料電池陰極催化劑的成本占很大的比例。本文采用微波協(xié)助乙二醇法制備燃料電池陰極催化劑,以降低燃料電池成本為核心,重點(diǎn)對(duì)提高燃料電池的催化活性和穩(wěn)定性進(jìn)行了研究。 用改進(jìn)的Hummers法制備了氧化石墨,采用常規(guī)干燥和低溫冷凍干燥兩種方式干燥樣品。將常規(guī)干燥的氧化石墨高溫膨脹得到膨脹后的氧化石墨,以膨脹后的氧化石墨為載體的前驅(qū)體,氯鉑酸為鉑源,分別研究了微波時(shí)間,溶劑比例,pH值對(duì)催化性能的影響。用X射線(xiàn)衍射儀(XRD),掃描電鏡(SEM),透射電鏡(TEM),傅里葉紅外光譜(FT-IR),拉曼光譜(Raman),循環(huán)伏安曲線(xiàn)(CV),線(xiàn)性?huà)呙枨�(xiàn)(LSV),時(shí)間電流曲線(xiàn)(i-t)等測(cè)試手段對(duì)催化劑進(jìn)行了表征,結(jié)果表明以膨脹后的氧化石墨為載體的前驅(qū)體,氯鉑酸的乙二醇溶液為鉑源,摻雜30%的去離子水的乙二醇溶液為還原劑,在微波時(shí)間為50s-(30s)-60s-(40s)-60s,不加助分散劑的條件下制備出的Pt/graphene催化劑的顆粒分布均勻,平均粒徑是2.4nm,電化學(xué)活性表面積大,鉑的利用率提高,催化劑的電化學(xué)性能優(yōu)異,半波電位為0.65V比商業(yè)催化劑的半波電位小0.01V,其電化學(xué)穩(wěn)定性遠(yuǎn)高于商業(yè)催化劑的電化學(xué)穩(wěn)定性。 為了降低鉑的含量,以膨脹后的氧化石墨為載體的前驅(qū)體制備了鉑鎳原子總的質(zhì)量分?jǐn)?shù)為20%的Pt-Ni/graphene催化劑,比較了不同鉑鎳比例1(mass%)催化劑的電化學(xué)性能,研究發(fā)現(xiàn)鉑鎳原子比為3：1的鉑鎳催化劑(Pt3Ni/graphene-1)的電化學(xué)性能較其它比例的鉑鎳催化劑的電化學(xué)性能好。研究表明該催化劑是合金結(jié)構(gòu),晶面間距是0.223nm,石墨烯上負(fù)載的顆粒的平均粒徑為2.7nm,合金顆粒分散均勻,該催化劑的半波電位是0.55V,比商業(yè)催化劑的半波電位小,但是電化學(xué)穩(wěn)定性高于商業(yè)催化劑。此外,還以冷凍干燥后的氧化石墨為載體的前驅(qū)體制備了鉑鎳比例為3：1的Pt3Ni/graphene-2催化劑,通過(guò)XRD, SEM, TEM等物理表征和電化學(xué)性能表征發(fā)現(xiàn),石墨烯上負(fù)載的粒子是合金顆粒,粒徑大小約為3.7nm,該催化劑的半波電位為0.50V,比商業(yè)催化劑的半波電位小,但是比商業(yè)催化劑的電化學(xué)穩(wěn)定性好。因此,石墨烯是燃料電池陰極催化劑的優(yōu)良載體,用其作為載體不僅可以提高負(fù)載粒子的利用率,而且還具有很好的耐腐蝕性和電化學(xué)穩(wěn)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，

本文編號(hào)：2491578