功能化石墨烯负载铂电催化剂的制备及其性能研究

发布时间：2018-05-12 01:27

本文选题：直接甲醇燃料电池 + 功能化石墨烯　；参考：《新疆大学》2015年硕士论文

【摘要】：直接甲醇燃料电池(DMFC)具有结构简单和能量转化效率高等特点,被认为是一种新型绿色的环保能源,越来越受到人们的关注。催化剂的活性和稳定性是影响DMFC商业化的重要因素之一。因此,制备具有较高催化活性和稳定性的催化剂成为DMFC的研究热点,其中载体对催化剂的性能起着关键性的作用;石墨烯具有良好的物理和化学性能,在催化剂载体方面有潜在的应用前景。本文以功能化石墨烯为载体负载Pt,制备了直接甲醇燃料电池阳极催化剂,并研究了电催化活性及稳定性。主要研究结果如下:1.采用高温热解聚苯胺修饰的氧化石墨烯(PANI-GO),通过改变氧化石墨烯与苯胺(GO/ANI)的质量比,制备了一系列氮掺杂还原氧化石墨烯碳材料(N-RGO),以其负载Pt合成了Pt/N-RGO纳米结构电催化剂。采用透射电镜(TEM)、X射线衍射谱(XRD)、拉曼光谱(Raman)及X射线光电子能谱(XPS)等技术对Pt/N-RGO的形貌及结构进行表征。用循环伏安和计时电流等电化学技术研究了Pt/N-RGO电极催化剂对CO溶出反应和甲醇电氧化反应的催化性能。发现GO/ANI质量比为1:1.3时所制备Pt/N-RGO(1:1.3)催化剂显示出最好的抗CO中毒能力;催化甲醇氧化的电流密度达到160.8 A·g-1;与未掺杂氮样品Pt/RGO相比,Pt/N-RGO(1:1.3)样品显示出更强的抗CO中毒能力和更高的甲醇电氧化催化活性及稳定性。2.以苯胺(ANI)及聚苯胺(PANI)对还原氧化石墨烯(RGO)进行非共价修饰,并以其为载体负载Pt制备了Pt/ANI-RGO和Pt/PANI-RGO催化剂。结果显示,ANI及PANI对RGO进行修饰能明显减小Pt纳米颗粒的尺寸和分布范围;ANI及PANI的引入,提高了催化剂Pt的电化学活性面积,所制备的Pt/ANI-RGO和Pt/PANI-RGO催化剂对甲醇氧化的催化活性(125.6 A·g-1和86.4 A·g-1)要高于Pt/RGO催化剂(77.3 A·g-1),但ANI及PANI对RGO的修饰对RGO负载的Pt电催化剂的催化稳定性没有影响。3.采用聚乙烯吡咯烷酮(PVP)非共价修饰的RGO为载体,以其负载Pt得到Pt/PVP-RGO催化剂。结果显示,Pt/PVP-RGO催化剂表面的Pt颗粒分布均匀、尺寸较小;相对于Pt/RGO催化剂而言,PVP的加入,对Pt/PVP-RGO催化剂甲醇氧化活性无显著改善;但Pt/PVP-RGO催化剂的稳定性(下降51%)明显高于Pt/RGO催化剂(下降62%),PVP的存在对催化剂稳定性的提高有一定的积极作用。4.利用甲基紫精(MV)非共价功能化RGO,并以其负载Pt制备了Pt/MV-RGO纳米催化剂。结果表明,Pt/MV-RGO催化剂表面的Pt颗粒分布状况和尺寸大小有明显改善;Pt/MV-RGO催化剂的电化学活性面积为24.7 m2·g-1,是Pt/RGO的3倍;同时,Pt/MV-RGO催化剂催化甲醇氧化的电流密度为221.4 A·g-1,是Pt/RGO的2.6倍;在氧还原反应中Pt/MV-RGO催化剂亦有着较高的催化活性,Pt/MV-RGO催化剂的稳定性也较好。
[Abstract]:Direct methanol fuel cell (DMFC), which has the characteristics of simple structure and high energy conversion efficiency, is considered as a new type of green environmental energy, which has attracted more and more attention. The activity and stability of the catalyst is one of the important factors affecting the commercialization of DMFC. Therefore, the preparation of catalysts with high catalytic activity and stability has become a research hotspot in DMFC, in which the support plays a key role in the performance of the catalyst, and graphene has good physical and chemical properties. It has potential application prospect in catalyst support. In this paper, the anode catalyst for direct methanol fuel cell was prepared with functionalized graphene as the carrier, and its electrocatalytic activity and stability were studied. The main results are as follows: 1. A series of nitrogen-doped reduced graphene oxide carbon materials (N-RGON) were prepared by changing the mass ratio of graphene oxide to aniline in the presence of high temperature Polyaniline modified graphene oxide (PANI-GON). A series of nitrogen-doped graphene oxide carbon materials (N-RGON) were prepared by supported Pt to synthesize Pt/N-RGO nanostructure electrocatalysts. The morphology and structure of Pt/N-RGO were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS). The catalytic properties of Pt/N-RGO electrode catalysts for CO dissolution and methanol electrooxidation were studied by cyclic voltammetry and chronoamperometry. When the mass ratio of GO/ANI is 1: 1.3, the catalyst prepared by Pt- / N-RGO1: 1.3) shows the best ability to resist CO poisoning. The current density of catalytic methanol oxidation reached 160.8 Ag-1.The Pt- / N-RGO1: 1.3) samples showed stronger resistance to CO poisoning and higher catalytic activity and stability of methanol electrooxidation than unadulterated nitrogen samples (Pt/RGO / RGO1: 1.3). Pt/ANI-RGO and Pt/PANI-RGO catalysts were prepared by noncovalent modification with aniline (ANI) and Polyaniline (Polyaniline), and supported on Pt. The results show that the modification of RGO by RGO and PANI can obviously reduce the size and distribution of Pt nanoparticles and increase the electrochemical active area of Pt. The catalytic activity of the prepared Pt/ANI-RGO and Pt/PANI-RGO catalysts for methanol oxidation was 125.6 Ag-1 and 86.4 Ag-1), which was higher than that of Pt/RGO catalyst 77.3 Ag-1G ~ (-1), but the modification of RGO by ANI and PANI had no effect on the catalytic stability of RGO supported Pt electrocatalyst. The non-covalent modified polyvinylpyrrolidone (PVP) RGO was used as the support and supported on Pt to obtain the Pt/PVP-RGO catalyst. The results showed that the Pt particles on the surface of PtP / PVP-RGO catalyst were uniformly distributed and the size of Pt particles was smaller than that of Pt/RGO catalyst, and the methanol oxidation activity of Pt/PVP-RGO catalyst was not significantly improved compared with the addition of PtPVP-RGO catalyst. However, the stability of Pt/PVP-RGO catalyst was significantly higher than that of Pt/RGO catalyst. Pt/MV-RGO nanocatalysts were prepared by non-covalent functionalization of methyl violet spermatine (MV) and supported on Pt. The results show that the distribution and size of Pt particles on the surface of Pt- / MV-RGO catalyst are obviously improved, the electrochemical activity area of Pt- MV-RGO catalyst is 24.7 m2 g ~ (-1), which is 3 times of that of Pt/RGO, and the current density of methanol oxidation is 221.4 Ag-1, 2.6 times of that of Pt/RGO, while the current density of Pt- / MV-RGO catalyst is 221.4 Ag-1. In the oxygen reduction reaction, Pt/MV-RGO catalyst also has higher catalytic activity. The stability of Pt- MV-RGO catalyst is better than that of Pt- MV-RGO catalyst.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TM911.4

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