Morphology dependent electrocatalytic properties of hydrothermally synthesized cobalt oxide nanostructures

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• 作者：Muhammad Mehmood Shahid ; Perumal Rameshkumar ; Nay Ming Huang ; ^{huangnayming@um.edu.my" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Cobalt oxide nanostructures ; Hydrothermal synthesis ; 4-nitrophenol ; Electrochemical sensor
• 刊名：Ceramics International
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：41
• 期：10
• 页码：13210-13217
• 全文大小：1341 K

文摘

Cobalt oxide (Co₃O₄) nanostructures with different morphologies (nanocubes, nanowires, nanobundles, nanoplates, and nanoflowers) were synthesized using a simple hydrothermal process and the electrochemical reduction of 4-nitrophenol (4-NP) was chosen as a model system to study the electrocatalytic properties of the Co₃O₄ nanostructures. The nanostructures were successfully characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman analysis. Further, glassy carbon (GC) electrodes modified with Co₃O₄ nanostructures with different morphologies were characterized using electrochemical impedance spectroscopy (EIS), and the results showed the lowest charge transfer resistance (R_ct) value for the Co₃O₄ nanocubes toward the [Fe(CN)₆]^3−/4− redox couple among all the modified electrodes. The electrochemical reduction of 4-nitrophenol (4-NP) was performed using the different Co₃O₄ nanostructure modified electrodes with phosphate buffer solution (PBS) (pH 7), and it was found that the Co₃O₄ nanocube modified electrode displayed a better catalytic current response. Moreover, the electrochemical detection of 4-NP at the lowest concentration levels was studied with the nanocube modified electrode using square wave voltammetry (SWV). A linear relationship was observed between the current response and the concentration (R²=0.997), and the limit of detection was found to be 0.93 µM. The Co₃O₄ nanocubes could reproduce the current responses in repeated experiments for the detection of 4-NP.