本工作以硝酸钴为前驱体，通过一步电沉积法在玻碳电极表面原位生长氢氧化钴纳米片，构建了电化学传感器，研究了其对NO2-离子的电催化行为，建立了快速测定NO2-离子的电化学方法。通过扫描电子显微镜（Scanning electron microscope，SEM）、能量散射光谱（Elemental energy spectrum analysis，EDX）和电化学技术对所获得的纳米材料的形貌和性能进行表征，进一步研究该修饰电极快速检测NO2-离子的电化学行为和电催化机理。结果表明，同一浓度NO2-离子在不同扫描速度与电流响应间成正比关系，得到Co(OH)2/GCE界面的电化学过程受吸附控制。Co(OH)2/GCE对NO2-离子展现了良好的电催化性能，检测线性范围为1~15 mmol/L，检测限为0.29 mmol/L（S/N=3）。该传感器具有快速制备、催化活性好、易操作以及检测耗时短等特点，适用于亚硝酸盐的现场快速筛查。

In this work, cobalt hydroxide nanocrystal sheet was prepared by one-step electrodeposition with cobalt nitrate as a precursor. The electrocatalytic behavior to NO2- ion of cobalt hydroxide was studied and the electrochemical sensor was constructed. The morphology and properties of Co(OH)2/GCE were characterized by scanning electron microscopy (SEM), elemental energy spectrum analysis (EDX) and electrochemical techniques, and the electrochemical behavior and electrocatalytic mechanism of NO2- ion were rapidly detected by the modified electrode. The results show that the same concentration of NO2- ion has a proportional relationship between different scanning rates and current, and the electrochemical process of the Co(OH)2/GCE interface is controlled by adsorption. Co(OH)2/GCE showed a good electro-catalytic performance for NO2- ions, with a linear range of 1~15 mmol/L and a detection limit of 0.29 mmol/L (S/N=3).The sensor exhibited rapid preparation, good catalytic activity and easy operation, which is suitable for rapid field screening of nitrite.