石墨纸基电极OER电催化性能的研究

发布时间：2018-02-27 03:20

  本文关键词： 柔性石墨纸 锰氧化物 镍铁双氢氧化物 电催化剂 OER反应 电沉积法 水热法　出处：《广西大学》2017年硕士论文　论文类型：学位论文

【摘要】：石墨纸是一种由石墨粉末压制而成的柔韧性良好的薄片材料,具有价格低廉、来源丰富、环境友好、耐高温高压等优点,主要应用于制造高温密封元件、微型器件的导热元件,同时它也是一种导电导热能力强且化学稳定性良好的柔性基底。本论文以石墨纸作为电极基底,采用电沉积法和水热法生长活性物质,通过探讨一系列合成条件对其性能的影响,制备出高性能的电催化剂。本论文的研究内容总结如下:首先,以乙酸锰和乙酸铵为原料,以石墨纸为活性基底,通过电沉积法生长锰氧化物沉积层。探讨了工艺条件如电流密度、温度、电镀液浓度等因素对电极OER催化性能的影响,获得了最优化的沉积条件。利用SEM、XRD和OER性能测试等手段对催化剂的形貌、结构和性能进行了研究。实验结果表明,在沉积电流密度为3 mA·cm-2,沉积温度70 ℃,采用0.02 mol·L-1 Mn(Ac)2 + 0.01 mol·L-1 NH4Ac溶液,制备出由纳米片堆积而成三维网络多孔结构,鉴于该结构具有良好的离子传输通道,以及较大的比表面积,电极呈现出了高的OER催化活性。进一步研究表明,350℃qF烧不会改变电极的纳米结构,还能提高其电催化性能。所得的煅烧电极在中性电解液溶液中也表现出优异的OER活性。其次,以Ni(N03)2和Fe(N03)3为电镀液,以石墨纸为基底,通过电沉积法生长无定型NiFe(OH)x沉积层。探讨了三种沉积模式包括恒电压、循环伏安和脉冲沉积法对电极OER催化性能的影响。对各种沉积模式下的最优化沉积条件进行了比较,利用SEM、XPS和OER性能等测试手段,探讨了沉积条件对产物形貌、价态及性能的影响。实验结果表明,采用脉冲沉积模式,Ni:Fe = 9:1,温度为50 ℃下制备出由纳米颗粒堆积形成的多孔结构性能最优。最后,以KMnO4为氧化剂,石墨纸为还原剂和基底,通过水热法进行氧化还原反应,获得MnO2沉积层。探讨了水热温度和反应时间对电极形貌的影响。利用SEM、XPS和OER性能测试手段对电极的形貌、价态和性能进行了研究。实验结果表明,在水热温度为140 ℃,反应时间为6h时得到的由纳米线和纳米颗粒相互包裹的网状结构,该结构拥有通畅的离子传输通道、较大的活性面积以及较强的MnO2附着力,使得电极呈现出高的OER活性。将MnO2沉积层溶解后获得新型的石墨纸基底,SEM表征结果显示,石墨纸表面形成密集的孔道结构,提供更多的活性位点,使得该基底比原始石墨纸具有更高的活性。
[Abstract]:Graphite paper is a kind of flexible sheet material made from graphite powder. It has the advantages of low price, rich source, friendly environment, high temperature and high pressure, etc. It is mainly used in manufacturing high temperature sealing element and heat conduction element of micro device. It is also a flexible substrate with strong thermal conductivity and good chemical stability. In this paper, graphite paper is used as electrode substrate and active substances are grown by electrodeposition and hydrothermal method. High performance electrocatalysts were prepared by studying the effects of a series of synthetic conditions on their properties. The main contents of this paper are summarized as follows: firstly, manganese acetate and ammonium acetate were used as raw materials and graphite paper as active substrate. Manganese oxide deposits were grown by electrodeposition. The effects of process conditions such as current density, temperature and concentration of electroplating solution on the catalytic performance of electrode OER were discussed. The optimum deposition conditions were obtained. The morphology, structure and properties of the catalyst were studied by means of OER and SEM. The results showed that the deposition temperature was 70 鈩，

本文编号：1540906