化学学报 ›› 2014, Vol. 72 ›› Issue (8): 920-926.DOI: 10.6023/A14030233 上一篇    下一篇

研究论文

溶剂热/水热法制备MnOx@rGO纳米复合材料及其氧还原催化性能

靳琪, 裴龙凯, 胡宇翔, 杜婧, 韩晓鹏, 程方益, 陈军   

  1. 先进能源材料化学教育部重点实验室 化学化工协同创新中心 南开大学化学学院 天津 300071
  • 收稿日期:2014-03-31 出版日期:2014-08-14 发布日期:2014-06-10
  • 通讯作者: 程方益 E-mail:fycheng@nankai.edu.cn
  • 基金资助:
    项目受国家自然科学基金优秀青年基金(No. 21322101)和重点项目(No. 21231005)、教育部“新世纪优秀人才支持计划”(No. ACET-13-0296)及111计划项目(No. B12015)资助

Solvo/Hydrothermal Preparation of MnOx@rGO Nanocomposites for Electrocatalytic Oxygen Reduction

Jin Qi, Pei Longkai, Hu Yuxiang, Du Jing, Han Xiaopeng, Cheng Fangyi, Chen Jun   

  1. Key Laboratory of Advanced Energy Materials Chemistry Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071
  • Received:2014-03-31 Online:2014-08-14 Published:2014-06-10
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 21322101, 21231005), Ministry of Education (No. ACET-13-0296) and 111 Project (No. B12015).

氧化还原催化剂是燃料电池和金属空气电池中影响其阴极性能的关键因素. 采用溶剂热/水热法,以氧化石墨烯(GO),MnSO4和KMnO4为原料可控制备了两种锰氧化物(MnOx)和还原氧化石墨烯(rGO)复合材料(Mn3O4@rGO,MnOOH@rGO)并研究了其氧还原电催化性能. 通过X射线粉末衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、热重(TG)等分析测试手段表征了Mn3O4@rGO与MnOOH@rGO的组成结构及形貌. 结果显示,在制备过程中GO被还原为rGO,乙醇和水溶剂中分别形成Mn3O4纳米颗粒与MnOOH纳米棒,MnOx均匀生长在rGO表面. 采用伏安曲线和旋转圆-环盘电极技术测试了所制备复合材料的电化学性能,并与无rGO负载的Mn3O4和MnOOH进行对比. 结果表明,由于MnOOH和rGO的协同作用,MnOOH@rGO在碱性体系中表现出较好的催化活性及稳定性,可作为潜在的氧还原催化剂.

关键词: 溶剂热/水热, 锰氧化物, 石墨烯, 纳米复合材料, 氧还原, 电催化剂

Oxygen reduction reaction (ORR) catalysts in the cathode electrode are of crucial importance in determining the electrochemical performance of fuel cells and metal air batteries. In this work, the hybrid materials composed of MnOx nanoparticles on reduced graphene oxide (rGO) were selectively prepared via solvo/hydrothermal process and investigated as catalysts for the ORR in alkaline solution. The synthesis involved one-step in-situ reaction of MnSO4, KMnO4 and graphene oxide (GO) to form MnOx nucleus, and growth of nanosized Mn3O4 or MnOOH on the rGO matrix in ethanol or water. The X-ray diffraction (XRD), Raman, and FTIR spectroscopies indicated the reduction of GO and the formation of Mn3O4 and MnOOH phase. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the Mn3O4 nanoparticles or MnOOH nanorods were homogenously dispersed over the few-layer rGO sheets. The MnOx content in the obtained MnOx@rGO composites was determined to be approximately 48% according to the TG analysis. The electrocatalytic properties of the prepared Mn3O4@rGO and MnOOH@rGO were evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and rotating ring-disk electrode (RRDE) techniques, and were compared with neat Mn3O4 and MnOOH. Among the tested samples, MnOOH@rGO exhibited superior ORR activity with a onset-potential of -0.11 V, a half-wave potential of -0.32 V and a high kinetic limiting current density (Jk) of 4.69 mA·cm-2 at -0.6 V. Furthermore, MnOOH@rGO enabled an apparent 4-electron reduction of oxygen and showed considerable durability. The superior performance of MnOOH@rGO hydrid hybrid was attributed to the synergistic effect of rGO substrate and MnOOH nanorods and indicated its promising application as efficient ORR catalyst.

Key words: solvo-hydrothermal, manganese oxides, graphene, nanocomposite materials, oxygen reduction, electrocatalysts