Exploring efficient and economical electrocatalysts for the oxygen evolution reaction (OER) is of great importance for large-scale water splitting. Transition-metal oxides and their derivatives have been explored as OER catalyst candidates owing to their earth-abundant reserves and environment-friendly features. However, their fewer electroactive sites and poor intrinsic activity of active sites greatly limit their catalytic efficiencies. Here, we successfully prepare misfit-layered-structured Bi₂Sr₂Co₂O_8+δ (BSCO) nanosheets via liquid exfoliation strategy. We find that the as-exfoliated nanosheets can serve as an efficient electrocatalyst for water oxidation. The single-unit-cell thick BSCO sheets exhibit promoted OER activity with the lower overpotential and smaller Tafel slope than the bulk counterpart. The improved performance is ascribed to the increased electrochemical surface areas and the enhanced activity of active sites due to the spin-state transition of cobalt ions at edge sites.

中文翻译：

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自旋态跃迁增强了错配层状氧化钴纳米片中的氧气释放活性。

探索用于氧释放反应（OER）的高效，经济的电催化剂对于大规模的水分解非常重要。过渡金属氧化物及其衍生物由于其丰富的地球储量和环境友好的特性，已被用作OER催化剂的候选材料。但是，它们较少的电活性位和活性位的固有活性差，极大地限制了它们的催化效率。在这里，我们成功地制备了错配层结构的Bi ₂ Sr ₂ Co ₂ O _{8 +δ}（BSCO）纳米片通过液体剥离策略。我们发现，剥落的纳米片可以用作水氧化的有效电催化剂。单单元厚的BSCO片材具有比大体积对应物低的过电势和较小的Tafel斜率，具有增强的OER活性。性能的提高归因于由于边缘位置处钴离子的自旋态跃迁而导致的电化学表面积增加和活性位点活性增强。