Bhatti Adeel Liaquat, Tahira Aneela, Kumar Shusheel, Ujjan Zaheer Ahmed, Bhatti Muhammad Ali, Kumar Sooraj, Aftab Umair, Karsy Amal, Nafady Ayman, Infantes-Molina Antonia, Ibupoto Zafar Hussain
Institute of Physics, University of Sindh Jamshoro 76080 Sindh Pakistan
Institute of Chemistry, Shah Abdul Latif University Khairpur Mirs Sindh Pakistan.
RSC Adv. 2023 Jun 16;13(26):17710-17726. doi: 10.1039/d3ra02555a. eCollection 2023 Jun 9.
The preparation of CoO nanostructures by a green method has been rapidly increasing owing to its promising aspects, such as facileness, atom economy, low cost, scale-up synthesis, environmental friendliness, and minimal use of hazardous chemicals. In this study, we report on the synthesis of CoO nanostructures using the milky sap of (CP) by a low-temperature aqueous chemical growth method. The milky sap of CP-mediated CoO nanostructures were investigated for oxygen evolution reactions (OERs) and supercapacitor applications. The structure and shape characterizations were done by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques. The prepared CoO nanostructures showed a heterogeneous morphology consisting of nanoparticles and large micro clusters. A typical cubic phase and a spinel structure of CoO nanostructures were also observed. The OER result was obtained at a low overpotential of 250 mV at 10 mA cm and a low Tafel slope of 53 mV dec. In addition, the durability of 45 hours was also found at 20 mA cm. The newly prepared CoO nanostructures using the milky sap of CP were also used to demonstrate a high specific capacitance of 700 F g at a current density of 0.8 A g and a power density of 30 W h kg. The enhanced electrochemical performance of CoO nanostructures prepared using the milky sap of CP could be attributed to the surface oxygen vacancies, a relatively high amount of Co, the reduction in the optical band gap and the fast charge transfer rate. These surface, structural, and optical properties were induced by reducing, capping, and stabilizing agents from the milky sap of CP. The obtained results of OERs and supercapacitor applications strongly recommend the use of the milky sap of CP for the synthesis of diverse efficient nanostructured materials in a specific application, particularly in energy conversion and storage devices.
由于其具有诸如简便性、原子经济性、低成本、可放大合成、环境友好性以及有害化学品使用量极少等诸多有前景的方面，通过绿色方法制备氧化钴纳米结构的研究正在迅速增加。在本研究中，我们报道了采用低温水热化学生长法，利用（CP）的乳汁合成氧化钴纳米结构。对CP介导的氧化钴纳米结构的乳汁进行了析氧反应（OER）和超级电容器应用研究。通过X射线衍射（XRD）、扫描电子显微镜（SEM）、能量色散光谱（EDS）和X射线光电子能谱（XPS）技术进行结构和形状表征。制备的氧化钴纳米结构呈现出由纳米颗粒和大型微团簇组成的异质形态。还观察到氧化钴纳米结构典型的立方相和尖晶石结构。在10 mA cm时，在250 mV的低过电位下获得了OER结果，塔菲尔斜率为53 mV dec。此外，在20 mA cm时还发现了45小时的耐久性。新制备的使用CP乳汁的氧化钴纳米结构在电流密度为0.8 A g和功率密度为30 W h kg时也表现出700 F g的高比电容。使用CP乳汁制备的氧化钴纳米结构增强的电化学性能可归因于表面氧空位、相对较高的钴含量、光学带隙的减小以及快速的电荷转移速率。这些表面、结构和光学性质是由CP乳汁中的还原、封端和稳定剂诱导产生的。OER和超级电容器应用的所得结果强烈建议在特定应用中，特别是在能量转换和存储设备中，使用CP乳汁来合成各种高效的纳米结构材料。
