Data_Sheet_1_Coupling Hierarchical Ultrathin Co Nanosheets With N-Doped Carbon Plate as High-Efficiency Oxygen Evolution Electrocatalysts.docx

The rational design of cost-effective and highly efficient catalysts for the oxygen evolution reaction (OER) is vastly desirable for advanced renewable energy conversion and storage systems. Tailoring the composition and architecture of electrocatalysts is a reliable approach for improving their catalytic performance. Herein, we developed hierarchical ultra-thin Co nanosheets coupled with N-doped carbon plate (Co-NS@NCP) as an efficient OER catalyst through a feasible and easily scalable NaCl template method. The rapid dissolution-recrystallization-carbonization synthesis process allows Co nanosheets to self-assemble into plenty of secondary building units and to distribute uniformly on N-doped carbon plate. Benefitting from the vertically aligned Co nanosheet arrays and hierarchical architecture, the obtained Co-NS@NCP possess an extremely high specific surface area up to 446.49 m2 g−1, which provides sufficient exposed active sites, excellent structure stability, and multidimensional mass transfer channels. Thus, the Co-NS@NCP affords remarkable electrocatalytic performance for OER in an alkaline medium with a low overpotential of only 278 mV at 10 mA cm−2, a small Tafel slope, as well as robust electrocatalytic stability for long-term electrolysis operation. The present findings here emphasize a rational and promising perspective for designing high-efficiency non-precious electrocatalysts for the OER process and sustainable energy storage and conversion system.

对氧析出反应（OER）的高效低成本催化剂的理性设计对于先进的可再生能源转换与存储系统极为渴求。通过精确调控电催化剂的组成与结构，是实现其催化性能提升的可靠途径。本研究中，我们通过一种可行且易于扩展的NaCl模板法，成功制备了具有分级超薄钴纳米片与氮掺杂碳板（Co-NS@NCP）复合结构的电催化剂，以其作为高效的OER催化剂。该快速溶解-再结晶-碳化合成过程使得钴纳米片能够自组装形成丰富的次级构建单元，并在氮掺杂碳板上均匀分布。得益于垂直排列的钴纳米片阵列和分级结构，所获得的Co-NS@NCP具有极高的比表面积（达446.49 m2 g−1），从而提供了充足的暴露活性位点、优异的结构稳定性和多维质量传输通道。因此，Co-NS@NCP在碱性介质中展现出卓越的电催化OER性能，在10 mA cm−2电流密度下，过电位仅为278 mV，Tafel斜率较小，并具有出色的电催化稳定性，适用于长期电解操作。本研究强调了一种合理且前景广阔的设计思路，旨在开发高效的非贵金属电催化剂，以应用于OER过程和可持续能源存储与转换系统。