Mugheri Abdul Qayoom, Tahira Aneela, Aftab Umair, Abro Muhammad Ishaq, Chaudhry Saleem Raza, Amaral Luís, Ibupoto Zafar Hussain
Dr M. A. Kazi Institute of Chemistry University of Sindh Jamshoro 76080 Sindh Pakistan
Department of Science and Technology, Linkoping University Campus Norrkoping SE-60174 Norrkoping Sweden.
RSC Adv. 2019 Feb 15;9(10):5701-5710. doi: 10.1039/c8ra10472g. eCollection 2019 Feb 11.
Due to the increasing energy consumption, designing efficient electrocatalysts for electrochemical water splitting is highly demanded. In this study, we provide a facile approach for the design and fabrication of efficient and stable electrocatalysts through wet chemical methods. The carbon material, obtained by the dehydration of sucrose sugar, provides high surface area for the deposition of NiO nanostructures and the resulting NiO/C catalysts show higher activity towards the OER in alkaline media. During the OER, a composite of NiO with 200 mg C can produce current densities of 10 and 20 mA cm at a bias of 1.45 V and 1.47 V RHE, respectively. Electrochemical impedance spectroscopy experiments showed the lowest charge transfer resistance and the highest double layer capacitance in the case of the NiO/C composite with 200 mg C. The presence of C for the deposition of NiO nanostructures increases the active centers and consequently a robust electrocatalytic activity is achieved. The obtained results in terms of the low overpotential and small Tafel slope of 55 mV dec for non-precious catalysts are clear indications for the significant advancement in the field of electrocatalyst design for water splitting. This composite material based on NiO/C is simple and scalable for widespread use in various applications, especially in supercapacitors and lithium-ion batteries.
由于能源消耗不断增加，迫切需要设计用于电化学水分解的高效电催化剂。在本研究中，我们通过湿化学方法提供了一种简便的方法来设计和制备高效稳定的电催化剂。通过蔗糖脱水获得的碳材料为NiO纳米结构的沉积提供了高表面积，所得的NiO/C催化剂在碱性介质中对析氧反应（OER）表现出更高的活性。在OER过程中，含有200 mg C的NiO复合材料在1.45 V和1.47 V（相对于可逆氢电极，RHE）的偏压下分别可产生10和20 mA cm的电流密度。电化学阻抗谱实验表明，含有200 mg C的NiO/C复合材料具有最低的电荷转移电阻和最高的双层电容。用于沉积NiO纳米结构的C的存在增加了活性中心，从而实现了强大的电催化活性。对于非贵金属催化剂，低过电位和55 mV dec的小塔菲尔斜率所获得的结果清楚地表明了水分解电催化剂设计领域的重大进展。这种基于NiO/C的复合材料简单且可扩展，可广泛用于各种应用，特别是在超级电容器和锂离子电池中。
