开发高效、廉价的电极材料应用于电催化氧析出反应(OER)在水分解技术中起着至关重要的作用. 提高催化剂催化活性的策略主要有两种, 一是通过调整催化剂形貌和结构来增加催化活性位点数量, 二是通过掺入其它组分来增强催化活性位点的反应活性. 本工作结合这两种策略, 通过原位电氧化方法成功合成了生长在碳布上具有独特三维结构的纳米多孔铁钴羟基氧化物(3D-FeCoOOH/CC), 合成的电极材料直接用作电催化析氧反应的工作电极. 以生长在碳布上的"微型棋子"阵列(MCPAs/CC)作为前驱体, 先后通过在(NH4)2Fe(SO4)2溶液中进行Fe掺杂工艺和在碱性介质中原位电化学氧化制备了3D-FeCoOOH/CC. 微观表征表明, MCPAs/CC上的"微型棋子"阵列完全转化为一层薄形涂层包覆在碳布纤维上. 电化学测试结果表明, 合成的3D-FeCoOOH/CC在1.0 mol L–1 KOH溶液中表现出优异的OER催化活性, 在电流密度为10 mA cm-2时所需的过电势仅为259 mV, 塔菲尔斜率为34.9 mV dec-1, 并且具有优异的稳定性. 详细的表征表明, 电化学表面积的增加、电导率的增高、FeCo双金属组成和独特的3D多孔结构共同使得3D-FeCoOOH/CC的催化OER活性增强. 此外, 本实验所应用的合成策略可以扩展到制备一系列其他过渡元素掺杂的Co基电极材料.
The development of highly efficient and cost-effective electrode materials for catalyzing the oxygen evolution reaction (OER) is crucial for water splitting technology. The increase in the number of active sites by tuning the morphology and structure and the enhancement of the reactivity of active sites by the incorporation of other components are the two main strategies for the enhancement of their catalytic performance. In this study, by combining these two strategies, a unique three-dimensional nanoporous Fe-Co oxyhydroxide layer coated on the carbon cloth (3D-FeCoOOH/CC) was successfully synthesized by in situ electro-oxidation methods, and directly used as a working electrode. The electrode, 3D-FeCoOOH/CC, was obtained by the Fe doping pro-cess in (NH4)2Fe(SO4)2, followed by continuous in situ electro-oxidization in alkaline medium of"micro go chess piece" arrays on the carbon cloth (MCPAs/CC). Micro characterizations illustrated that the go pieces of MCPAs/CC were completely converted into a thin conformal coating on the carbon cloth fibers. The electrochemical test results showed that the as-synthesized 3D-FeCoOOH/CC exhibited enhanced activity for OER with a low overpotential of 259 mV, at a cur-rent density of 10 mA cm–2, and a small Tafel slope of 34.9 mV dec–1, as well as superior stability in 1.0 mol L–1 KOH solution. The extensive analysis revealed that the improved electrochemical surface area, conductivity, Fe-Co bimetallic composition, and the unique 3D porous structure together con-tributed to the enhanced OER activity of 3D-FeCoOOH/CC. Furthermore, the synthetic strategy applied in this study could be extended to fabricate a series of Co-based electrode materials with the dopant of other transition elements.