石墨烯/碳化钴钼复合材料作为微生物燃料电池阴极催化剂的研究

Graphene/Co-Mo carbide as cathodic catalyst in microbial fuel cells

用改良Hummers法和碳热还原法分别制备了石墨烯和碳化钴钼。用透射电镜(TEM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)表征了材料的形貌和结构。用循环伏安(CV)表征了其氧还原(ORR)催化性能,结果表明,复合材料的氧还原峰电流和起峰电位均大大优于单一材料。旋转圆盘电极(RDE)实验表明复合材料的氧还原反应为高效的四电子转移过程。含有6 mg·cm^(-2)石墨烯/碳化钴钼复合材料作为阴极催化剂的微生物燃料电池(MFCs)最大功率密度为418 mW·m^(-2),达到商业铂碳的68.3%。因此,廉价的石墨烯/碳化钴钼复合材料作为MFCs阴极氧还原催化剂具有巨大的应用潜力。

Graphene and Co-Mo carbide were prepared by a modified Hummers＇ method and carbothermal reduction,respectively. The morphologies of the materials were studied using transmission electron microscopy（ TEM） and scanning electron microscopy（ SEM）,and the structures were characterized using X-ray diffraction（ XRD）. The electrocatalytic activities of the materials for oxygen reduction were measured by cyclic voltammetry（ CV）. The results revealed that a graphene /Co-Mo carbide composite exhibited better electrocatalytic activity towards oxygen reduction than pure graphene or Co-Mo carbide,with a higher oxygen reduction peak current and greater positive onset potential. The rotating disk electrode（ RDE） test revealed that the oxygen reduction reaction in the graphene / Co-Mo carbide composite proceeded via an efficient four-electron transfer process. A microbial fuel cell（ MFC） assembled using 6 mg·cm^（-2）of the graphene / Co-Mo carbide composite as a catalytic cathode delivered a power density of 418 m W·m-2,which was 68. 3% of the value of an MFC using a Pt/C-catalyst cathode,meaning inexpensive graphene / Co-Mo carbide composites have great potential for application as oxygen reduction catalysts in MFC cathodes.