Developing efficient electrocatalysts consisting of earth-abundant elements for oxygen evolution reaction (OER) is crucial for energy devices and technologies. Herein, we report self-supported highly porous nitrogen-doped graphene foam synthesized through the electrochemical expansion of carbon-fiber paper and subsequent nitrogen plasma treatment. A thorough characterization, such as electron microscopy and synchrotron-based near-edge X-ray absorption fine structure, indicates the well-developed porous structures featuring homogeneously doped nitrogen heteroatoms. These merits ensure enriched active sites, an enlarged active surface area, and improved mass/electron transport within the continuous graphene framework, thus leading to an outstanding capability toward electrocatalyzing OER in alkaline media, even competitive with the state-of-the-art noble-/transition-metal and nonmetal electrocatalysts reported to date, from the perspectives of the sharp onset potential, a small Tafel slope, and remarkable durability. Furthermore, a rechargeable Zn–air battery with this self-supported electrocatalyst directly used as the air cathode renders a low charge/discharge overpotential and considerable life span. The finding herein suggests that a rational methodology to synthesize graphene-based materials can significantly enhance the oxygen electrocatalysis, thereby promoting the overall performance of the energy-related system.

中文翻译：

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可扩展的自支撑石墨烯泡沫，可实现高性能的电催化氧分解

开发用于氧释放反应（OER）的由富含地球元素的高效电催化剂对于能源设备和技术至关重要。在本文中，我们报道了通过碳纤维纸的电化学膨胀和随后的氮等离子体处理合成的自支撑的高孔隙度氮掺杂石墨烯泡沫。诸如电子显微镜和基于同步加速器的近边缘X射线吸收精细结构等全面表征表明，发达的多孔结构具有均匀掺杂的氮杂原子。这些优点可确保在连续石墨烯框架内富集活性位点，扩大活性表面积并改善质量/电子传输，从而在碱性介质中具有出色的电催化OER的能力，从急剧上升的电势，小的Tafel斜率和出色的耐用性的角度来看，它甚至可以与迄今报道的最先进的贵金属/过渡金属和非金属电催化剂竞争。此外，带有这种自支撑式电催化剂的可再充电Zn-空气电池可直接用作空气阴极，从而降低了充电/放电过电位，并延长了使用寿命。本文的发现表明，合成石墨烯基材料的合理方法学可以显着增强氧的电催化作用，从而促进能源相关系统的整体性能。带有这种自支撑式电催化剂的可再充电锌空气电池直接用作空气阴极，可实现低的充电/放电过电位和可观的使用寿命。本文的发现表明，合成石墨烯基材料的合理方法学可以显着增强氧的电催化作用，从而促进能源相关系统的整体性能。带有这种自支撑式电催化剂的可再充电锌空气电池直接用作空气阴极，可实现低的充电/放电过电位和可观的使用寿命。本文的发现表明，合成石墨烯基材料的合理方法学可以显着增强氧的电催化作用，从而促进能源相关系统的整体性能。