简单一步法合成Co9S8氧还原反应电催化剂

A Facile One-step Synthesis of Co9S8 Electrocatalyst for Oxygen Reduction Reaction

摘要:

采用低温回流技术,以Co₄(CO)₁₂和S粉为原料,在1, 6-己二醇溶剂中一步合成了钴硫化物催化剂。用X射线衍射仪和扫描电子显微镜对合成的化合物进行了表征。XRD分析表明合成样品为立方结构的Co₉S₈化合物,其SEM图片显示了花椰菜状的表面形貌。Co₉S₈化合物表现出良好的氧还原催化活性,开路电位为0.75 V(vs. NHE)。在电荷转移控制电位区,电极反应传递系数和塔菲尔斜率分别为0.50和119 mV。同时,将催化剂的催化活性和电化学稳定性与商业铂催化剂进行了比较。

关键词:氧还原; 非贵金属催化剂; 钴硫化合物; 聚合物电解质膜燃料电池

Abstract:

A Co-based chalcogenide electrocatalyst has been synthesized by a facile one-step reaction of dodecacarbonyltetracobalt [Co₄(CO)₁₂] and elemental sulfur in 1, 6-hexanediol solvent under refluxing conditions. The characterizations of the synthesized compound are performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD shows the formation of cubic structure Co₉S₈ and SEM micrograph displays cauliflower-like surface morphologies. The catalyst has an open circuit potential (OCP) of 0.75 V (vs. NHE) and shows a promising catalytic activity for the oxygen reduction. The transfer coefficient and Tafel slope are calculated to be 0.50 and 119 mV in the potential region limited by charge transfer kinetics, respectively. The catalytic activity and the electrochemical stability of the catalyst have also been compared with a commercial Pt catalyst.

Key words:oxygen reduction; non-noble metal catalyst; cobalt sulfide; polymer electrolyte membrane fuel cells