Muthukumar Pandi, Nantheeswaran Periyappan, Mariappan Mariappan, Pannipara Mehboobali, Al-Sehemi Abdullah G, Anthony Savarimuthu Philip
Department of Chemistry, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai-600077, Tamil Nadu, India.
Department of Chemistry, SRM IST, Kattankulathur, Chennai-603203, Tamil Nadu, India.
Dalton Trans. 2023 Mar 21;52(12):3877-3883. doi: 10.1039/d2dt04169c.
Fluorine and nitrogen codoped cobalt hydroxide-graphene oxide nanocomposites (N,F-Co(OH)/GO) were synthesized by a simple hydrothermal method and demonstrated highly enhanced oxygen evolution activity in an alkaline medium. N,F-Co(OH)/GO synthesized under optimized reaction conditions required an overpotential of 228 mV to produce the benchmark current density of 10 mA cm (scan rate 1 mV s). In contrast, N,F-Co(OH) without GO and Co(OH)/GO without fluorine required higher overpotentials (370 (N,F-Co(OH)) and 325 mV (Co(OH)/GO)) for producing the current density of 10 mA cm. The low Tafel slope (52.6 mV dec) and charge transfer resistance, and high electrochemical double layer capacitance of N,F-Co(OH)/GO compared to N,F-Co(OH) indicate faster kinetics at the electrode-catalyst interface. The N,F-Co(OH)/GO catalyst showed good stability over 30 h. High-resolution transmission electron microscope (HR-TEM) images showed good dispersion of polycrystalline Co(OH) nanoparticles in the GO matrix. X-ray photoelectron spectroscopic (XPS) analysis revealed the coexistence of Co/Co and the doping of nitrogen and fluorine in N,F-Co(OH)/GO. XPS further revealed the presence of F in its ionic state and being covalently attached to GO. The integration of highly electronegative F with GO stabilizes the Co active centre along with improving the charge transfer and adsorption process that contributes to improved OER. Thus, the present work reports a facile method for preparing F-doped GO-Co(OH) electrocatalysts with enhanced OER activity under alkaline conditions.
通过简单的水热法合成了氟和氮共掺杂的氢氧化钴-氧化石墨烯纳米复合材料（N,F-Co(OH)/GO），并证明其在碱性介质中具有高度增强的析氧活性。在优化反应条件下合成的N,F-Co(OH)/GO产生10 mA cm基准电流密度（扫描速率1 mV s）所需的过电位为228 mV。相比之下，不含GO的N,F-Co(OH)和不含氟的Co(OH)/GO产生10 mA cm电流密度需要更高的过电位（分别为370 mV（N,F-Co(OH)）和325 mV（Co(OH)/GO））。与N,F-Co(OH)相比，N,F-Co(OH)/GO的低塔菲尔斜率（52.6 mV dec）和电荷转移电阻以及高电化学双层电容表明电极-催化剂界面处的动力学更快。N,F-Co(OH)/GO催化剂在30 h内表现出良好的稳定性。高分辨率透射电子显微镜（HR-TEM）图像显示多晶Co(OH)纳米颗粒在GO基质中分散良好。X射线光电子能谱（XPS）分析揭示了N,F-Co(OH)/GO中Co/Co的共存以及氮和氟的掺杂。XPS进一步揭示了离子态F的存在并与GO共价连接。高电负性F与GO的整合稳定了Co活性中心，同时改善了电荷转移和吸附过程，有助于提高析氧反应。因此，本工作报道了一种在碱性条件下制备具有增强析氧活性的F掺杂GO-Co(OH)电催化剂的简便方法。
