【作者】 尹翠蕾；

【导师】 王贵领；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2009， 硕士

【摘要】 目前过氧化氢基燃料电池阴极电还原的催化剂主要是贵金属,因其价格昂贵、资源稀缺而增加了燃料电池的成本。研究对过氧化氢(H2O2)电还原具有高催化活性和选择性、良好稳定性、价格低廉的催化剂具有重大意义。本论文利用在液相溶液中的直接生长法制备了四氧化三钴(Co3O4)、钴酸镍(NiCo2O4)纳米线电极和B型氢氧化镍(B-Ni(OH)2)电极,并用X射线衍射分析(XRD)、透射电镜(TEM)、扫描电镜(SEM)、比表面积分析(BET)等手段进行表征。XRD图谱表明所制备的纳米线分别为尖晶石构型的Co3O4和NiCO2O4,纳米片层为B-Ni(OH)2。扫描电镜和透射电镜表征表明Co3O4和NiCo2O4纳米线阵列全部由直径约为500 nm、长度约为15μm的均匀纳米线组成,Ni(OH)2电极表面为B-Ni(OH)2的纳米片层晶体。BET测定Co3O4纳米线的比表面积约为84.76 m2.g-1,NiCo2O4纳米线的比表面积约为97.90 m2·g-1。以循环伏安法测试了Co3O4、NiCo2O4纳米线电极以及β-Ni(OH)2电极在氢氧化钠(NaOH)溶液中对H2O2电还原的催化性能,结果表明Co3O4、NiCo2O4纳米线电极在3 mol·L-1 NaOH溶液中具有非常高的催化活性和稳定性,β-Ni(OH)2电极活性稍差,但仍具有其本身的优越性。当H2O2浓度为0.4mol·L-1、电极电势为-0.4 V时,Co3O4纳米线电极表面的电流密度达到了103.88 mA·cm-2,NiCo2O4纳米线电极表面的电流密度达到-124.86 mA·cm-2,β-Ni(OH)2纳米片层电极则较低。计时电流法测试表明Co3O4纳米线电极和NiCo2O4纳米线电极在碱性溶液中稳定性优良。直接生长法制备的纳米线电极与粉末涂覆法制备的电极相比,活性更高、稳定性更佳,且此法更加简便。更多还原

【Abstract】 Current cathode catalysts for Fuel cells using hydrogen peroxide as oxidant are noble metals, but they are so expensive and scarce that they will raise the costs of the fuel cells largely. Therefore, research on the catalysts having high activity, high selectivity, good stability and low-cost is of great significance.In this paper, Co3O4、NiCo2O4 nanowire electrode and Ni(OH)2 electrode were synthesized using a solution-based synthetic route, respectively, and characterized by X-diffraction spectroscopy (XRD)、transmission electron microscopy (TEM)、scanning electron microscopy(SEM) and BET measurement. XRD pattern indicated that the structure of the nanowires are spinel Co3O4、NiCo2O4, respectively. The nanolayer isβ-Ni(OH)2. SEM and TEM characterization show that the Co3O4、NiCo2O4 nanowire arrays are made up of nanowires with diameters of 500 nm and lengths up to 15μm, Ni(OH)2 electrode is fabricated byβ-Ni(OH)2 crystallizing layers. BET measurement shows that the nanowires of Co3O4、NiCo2O4 have a surface area of 84.76 m2·g-1、97.90 m2·g-1.Their performance for hydrogen peroxide electro-reduction in NaOH solution were investigated by Cyclic voltammogram and chronoamperometry test. Results revealed that Co3O4、NiCo2O4 nanowire electrodes exhibit high activity and good stability for electrocatalytic reduction of H2O2 in 3 mol·L-1 NaOH solution. The activity of Ni(OH)2 electrode is not as good as the Co3O4、NiCo2O4 nanowire electrodes, but it also shows its superiority. A current density of as high as-103.88 mA·cm-2、-124.86 mA·cm-2 was achieved on the Co3O4 nanowire and the NiCo2O4 nanowire electrode when hydrogen peroxide concentration was 0.4 mol·L-1、the potential was-0.4 V. But it was much lower on theβ-Ni(OH)2 nanolayer electrode. Comparing to the nickel foam electrode filled with corresponding powder, these nanowire electrodes show better activity and greater stability, and the methods of the preparation of them are more simple and convenient.更多还原