一步热解核黄素制备高性能氧还原反应电催化剂（英文）

发布时间：2018-03-19 23:26

本文选题：核黄素　切入点：热解　出处：《催化学报》2017年10期 　论文类型：期刊论文

【摘要】：质子交换膜燃料电池具有零污染、能量密度高、操作温度低和超静低音等优点,因而广泛应用于新能源汽车动力电源.然而质子交换膜燃料电池阴极氧还原反应(ORR)过程缓慢且复杂,因此需要大量的高性能ORR电催化剂.商品铂基催化剂是目前最为广泛使用的ORR催化剂,然而其高昂的价格阻碍了燃料电池汽车的商业化进程.因此,近年来人们致力于研发高性能的非贵金属ORR催化剂,并成功获得了具有高ORR活性及优异稳定性的催化剂.然而开发贵金属替代催化剂还存在制备过程较为复杂、单体有毒等缺点.核黄素具有成本低廉、无毒、氮含量高等优点,本文将其直接作为碳源和氮源,以无水氯化铁为铁前驱体,通过简单的一步热解法制备了高性能的Fe N C催化剂.表征结果表明,合成的催化剂表面由于氮的掺杂导致石墨烯存在较多的缺陷,其比表面积为301 m~2g~( 1)且孔径分布主要位于45 nm处;催化剂由很薄、卷曲的石墨烯片层和一些颗粒组成,其中的碳材料高度石墨化且存在Fe_2O_3晶体.结合X射线光电子能谱和催化剂的ORR活性,推导出石墨化氮为ORR的主要活性位,铁在ORR反应中也起着重要作用.在氧气饱和的0.1 mol L~( 1) KOH溶液中,Fe N C催化剂的ORR活性达到4.16 mA cm~( 2),与商品Pt/C催化剂相当(4.46 mA cm~( 2)).采用计时电流法在0.66 V(相对于RHE电位)下运行3 h后,Fe N C催化剂电流仅下降了3%,而Pt/C催化剂下降了40%,表明Fe N C催化剂与Pt/C催化剂具有相近的ORR活性,但稳定性比Pt/C催化剂更出色.测试结果表明,Fe N C催化剂的抗甲醇毒化性能远优于Pt/C催化剂.在酸性介质中,Fe N C催化剂的ORR活性比Pt/C催化剂低,但稳定性更高.总之,该Fe N C催化剂在碱性介质中有较高的活性和稳定性,在酸性介质中有较高的稳定性.因此,我们采用廉价、无毒的核黄素作为碳氮源,通过简单的一步热解法制备出的Fe N C催化剂能较好地满足燃料电池ORR催化剂高性能和低成本的要求,具有很好的应用前景.
[Abstract]:Proton exchange membrane fuel cells have the advantages of zero pollution, high energy density, low operating temperature and super static bass. However, the process of cathode oxygen reduction reaction of proton exchange membrane fuel cell (PEMFC) is slow and complex. Therefore, a large number of high performance ORR electrocatalysts are needed. Commercial platin-based catalysts are the most widely used ORR catalysts at present, but their high price hinders the commercialization of fuel cell vehicles. In recent years, people have been devoted to the development of high performance non-precious metal ORR catalysts, and successfully obtained catalysts with high ORR activity and excellent stability. Riboflavin has the advantages of low cost, nontoxic and high nitrogen content. In this paper, riboflavin is directly used as carbon and nitrogen source, and anhydrous ferric chloride is used as iron precursor. A simple one-step pyrolysis method was used to prepare high performance Fe _ N _ N _ (C) catalysts. The characterization results show that there are many defects in graphene on the surface of the synthesized catalysts due to the doping of nitrogen. The specific surface area of the catalyst is 301 mm2 / 2g-1 and the pore size distribution is located mainly at 45 nm. The catalyst consists of very thin crimped graphene lamellae and some particles. The carbon materials are highly graphitized and have Fe_2O_3 crystals. Combined with X-ray photoelectron spectroscopy and the ORR activity of the catalyst, the graphitized nitrogen is the main active site of ORR. Iron also plays an important role in the ORR reaction. In oxygen saturated 0.1 mol L ~ (1) KOH solution, the ORR activity of Fe ~ (2 +) N ~ (2 +) C catalyst reaches 4.16 Ma / cm ~ (-1), which is comparable to that of commercial Pt/C catalyst. The chronoamperometric method is used at 0.66 V (relative to that of commercial Pt/C catalyst). After running at RHE potential for 3 h, the current of the catalyst only decreased by 3%, while that of the catalyst of Pt/C decreased by 40%, which indicated that the catalyst had similar ORR activity to that of the Pt/C catalyst. However, the stability of the catalyst is better than that of the Pt/C catalyst. The test results show that the methanol-resistant activity of the catalyst is much better than that of the Pt/C catalyst. The ORR activity of the catalyst is lower than that of the Pt/C catalyst in acid medium, but the stability is higher. The catalyst has higher activity and stability in alkaline medium and higher stability in acidic medium. Therefore, the cheap, nontoxic riboflavin is used as carbon and nitrogen source. The Fe _ N _ N _ (C) catalyst prepared by a simple one-step pyrolysis method can meet the requirements of high performance and low cost for fuel cell ORR catalyst and has a good prospect of application.
【作者单位】：西南石油大学材料科学与工程学院油气藏地质与开发国家重点实验室;
【基金】：supported by Open Project from State Key Laboratory of Catalysis(N-14-1) Scientific Research Foundation for Returned Scholars,Ministry of Education of China International Technology Collaboration of Chengdu Science and Technology Division~~
【分类号】：O643.36;TM911.4

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