Activating the Basal Planes and Oxidized Oxygens in Layer-Structured Na 0.6 CoO 2 for Boosted OER Activity.

With the CoO 2 slabs consisting of Co 4 O 4 cubane structure, layered Na x CoO 2 are considered promising candidates for oxygen evolution reaction (OER) in alkaline media given their earth-abundant and structural advantages. However, due to the strong adsorption of intermediates on the large basal planes, Na x CoO 2 cannot meet the activity demands. Here, a novel one-pot synthesis strategy is proposed to realize the high solubility of iron in Na x CoO 2 in an air atmosphere. The optimist Na 0.6 Co 0.9 Fe 0.1 O 2 exhibits enhanced OER activity compared to their pristine and other reported Fe-doped Na x CoO 2 counterparts. Such an enhancement is mainly ascribed to the abundant active sites on the activated basal planes and the participation of oxidized oxygen as active sites independently, which breaks the scaling relationship limit in the OER process. This work is expected to contribute to the understanding of the modification mechanism of Fe-doped cobalt-based oxides and the exploitation of layer-structured oxides for energy application.