Activating Both Basal Plane and Edge Sites of Layered Cobalt Oxides for Boosted Water Oxidation
Yu Li, Gao Chen, Yanping Zhu, Zhiwei Hu, Ting‐Shan Chan, Sixuan She, Jie Dai, Wei Zhou, Zongping Shao
Abstract
Abstract Layered A x CoO 2 materials built by stacking layers of CoO 2 slabs and inserting alkali ions in between them have shown a promising activity of oxygen evolution reaction (OER) due to their active edge sites. However, the large basal plane areas of the CoO 2 slabs show too strong adsorption energy to the reaction intermediates, which is unfavorable for the release of O 2 . Here, a simple cation‐exchange strategy based on Fe 3+ and alkali ions is proposed to simultaneously activate both the basal plane and edge sites of A x CoO 2 for the OER. X‐ray absorption spectroscopy has revealed that the Fe 3+ ions deposit both on the surface and edge sites of the CoO 2 slabs and enter the interlayer. The cation‐exchanged A x CoO 2 electrodes show a boosted activity compared to their pristine and conventional Fe‐doped A x CoO 2 counterparts. This phenomenon is mainly ascribed to the abundant edge‐sharing Co–Fe motifs at the edge sites and the charge redistribution in the basal plane sites induced by the insertion of Fe 3+ ions. This work provides a novel method to fully exploit layer‐structured materials for efficient energy conversion.