Mannu Pandian, Dharman Ranjith Kumar, Nga Ta Thi Thuy, Mariappan Athibala, Shao Yu-Cheng, Ishii Hirofumi, Huang Yu-Cheng, Kandasami Asokan, Oh Tae Hwan, Chou Wu-Ching, Chen Chi-Liang, Chen Jeng-Lung, Dong Chung-Li
Department of Physics, Tamkang University, New Taipei City, 25137, Taiwan.
School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, South Korea.
Small. 2024 Oct 21:e2403744. doi: 10.1002/smll.202403744.
The development of an excellent multifunctional electrocatalyst that is based on non-precious metal is critical for improving the electrochemical processes of the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the urea oxidation reaction (UOR) in alkaline media. This study demonstrates that incorporating Mo into CoO facilitated the formation of rich oxygen vacancies (Vo), which promotes effective nitrate adsorption and activation in urea electrolysis. Subsequently, in situ/operando X-ray absorption spectroscopy is used to explore the active sites in Mo-CoO-3 under OER, indicating the oxygen vacancies are first filled with OH in Mo-CoO; facilitated the pre-oxidation of low-valence Co, and promoted the reconstruction/deprotonation of intermediate Co-OOH. Mo-CoO-3 electrocatalysts show impressive HER, OER, and UOR with low overpotentials of 141 mV, 220 mV, and 1.32 V, respectively, at 10 mA cm in an alkaline medium. Furthermore, in situ/Operando Raman spectroscopy results reveal the importance of CoOOH active sites for enhanced electrochemical performance in Mo-CoO-3 compared to the pure CoO. The urea electrolyzer with Mo-CoO electrocatalysts acts as an anode and the cathode delivers 1.42 V at 10 mA cm. A viable approach to creating effective UOR electrocatalysts involves synergistic engineering exploiting doping and oxygen vacancies.
开发一种基于非贵金属的优异多功能电催化剂对于改善碱性介质中析氢反应(HER)、析氧反应(OER)和尿素氧化反应(UOR)的电化学过程至关重要。本研究表明,将Mo掺入CoO中有助于形成丰富的氧空位(Vo),这促进了尿素电解中硝酸盐的有效吸附和活化。随后,采用原位/操作X射线吸收光谱法探究了Mo-CoO-3在OER条件下的活性位点,表明在Mo-CoO中氧空位首先被OH填充;促进了低价Co的预氧化,并促进了中间产物Co-OOH的重构/去质子化。在碱性介质中,Mo-CoO-3电催化剂在10 mA cm时分别表现出令人印象深刻的HER、OER和UOR,过电位分别为141 mV、220 mV和1.32 V。此外,原位/操作拉曼光谱结果揭示了与纯CoO相比,CoOOH活性位点对增强Mo-CoO-3电化学性能的重要性。采用Mo-CoO电催化剂的尿素电解槽作为阳极,阴极在10 mA cm时的电压为1.42 V。一种创建有效的UOR电催化剂的可行方法是利用掺杂和氧空位进行协同工程设计。