CoSeO3化合物的制备及对阴极氧还原的催化性能

以Co₄(CO)₁₂和Se为原料, 采用低温回流方法在乙二醇介质中合成了CoSeO₃化合物。利用扫描电镜(SEM)、X射线衍射仪(XRD)和旋转圆盘电极(RDE)技术表征合成的化合物微观形貌、结构特征和电化学性能。这种化合物主要由单斜结构的CoSeO₃?H₂O晶粒组成, 粒径大小约为26.7 nm, 具有规则的晶体外形。在25℃, 0.5 mol/L H₂SO₄电解液中, CoSeO₃化合物对氧还原反应(ORR)表现出明显的电催化活性, 开路电位为0.80 V(vs NHE)。根据Koutecky-Levich方程计算出每个氧分子还原过程转移的电子数约为3.8。在0.64~0.76 V(vs NHE)电位范围内, 测得催化剂的传递系数、Tafel斜率和交换电流密度分别为0.50、119 mV和1.98×10^-6 mA/cm²。CoSeO₃化合物的催化活性和电化学稳定性也与商品Pt催化剂进行了比较。

Synthesis and Performance of CoSeO3 Compound as a Cathodic Catalyst for Oxygen Reduction

Novel CoSeO₃ nanoparticles were successfully synthesized by low temperature refluxing method using dodecacarbonyltetracobalt Co₄(CO)₁₂] and selenium (Se) as raw materials in glycol solvent. The crystalline structure, morphology and electrochemical performances of the as-prepared product were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and rotating disk electrode (RDE) technique. Results show that the as-obtained CoSeO₃ compound presents the structural characteristics of monoclinic CoSeO₃?H₂O with the particle size of 26.7 nm and regular figure. The catalyst demonstrates significant electrocatalytic activity towards oxygen reduction reaction (ORR), showing an open circuit potential (OCP) of 0.80 V (vs NHE) in 0.5 mol/L H₂SO₄ solution at 25℃. The transfer process of about 3.8 electrons is determined during the reduction per oxygen molecule by using Koutecky-Levich equation. The transfer coefficient, Tafel slope and exchange current density are 0.50, 119 mV and 1.98×10^-6 mA/cm² in the potential region of 0.64–0.76 V (vs NHE), respectively. The catalytic activity and electrochemical stability of the catalyst are compared with a commercial Pt catalyst.