Ji Dongxiao, Fan Li, Tao Lu, Sun Yingjun, Li Menggang, Yang Guorui, Tran Thang Q, Ramakrishna Seeram, Guo Shaojun
Department of Materials Science & Engineering, College of Engineering, Peking University, Beijing, 100871, China.
Department of Mechanical Engineering, National University of Singapore, 117574, Singapore, Singapore.
Angew Chem Int Ed Engl. 2019 Sep 23;58(39):13840-13844. doi: 10.1002/anie.201908736. Epub 2019 Aug 14.
Structure and defect control are widely accepted effective strategies to manipulate the activity and stability of catalysts. On a freestanding hierarchically porous carbon microstructure, the tuning of oxygen vacancy in the embedded hollow cobaltosic oxide (Co O ) nanoparticles is demonstrated through the regulation of nanoscale Kirkendall effect. Starting with the embedded cobalt nanoparticles, the concentration of oxygen-vacancy defect can vary with the degree of Kirkendall oxidation, thus regulating the number of active sites and the catalytic performances. The optimized freestanding catalyst shows among the smallest reversible oxygen overpotential of 0.74 V for catalyzing oxygen reduction/evolution reactions in 0.1 m KOH. Moreover, the catalyst shows promise for substitution of noble metals to boost cathodic oxygen reactions in portable zinc-air batteries. This work provides a strategy to explore catalysts with controllable vacancy defects and desired nano-/microstructures.
结构和缺陷控制是广泛认可的用于调控催化剂活性和稳定性的有效策略。在一种独立的分级多孔碳微结构上，通过纳米级柯肯达尔效应的调控，展示了对嵌入的中空钴氧化物（Co₃O₄）纳米颗粒中氧空位的调节。从嵌入的钴纳米颗粒开始，氧空位缺陷的浓度会随着柯肯达尔氧化程度而变化，从而调节活性位点的数量和催化性能。优化后的独立催化剂在0.1 m KOH中催化氧还原/析出反应时，展现出仅0.74 V的最小可逆氧过电位。此外，该催化剂有望替代贵金属，以促进便携式锌空气电池中的阴极氧反应。这项工作提供了一种探索具有可控空位缺陷和所需纳米/微观结构催化剂的策略。
