The hierarchical porous nitrogen-doped two-dimensional carbon (HNGC) was prepared by simple calcination of magnesium sulfate (MgSO₄) and self-synthesized nitrogen-doped two-dimensional graphene-like carbon at a mild temperature in oxygen. The influence MgSO4 on the morphology, structure and chemical composition of the prepared HNGC samples were studied using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, surface area analysis, X-ray photoelectron microscopy and elemental analyzer. HNGC-2 exhibited a uniform three-dimensional coral-like porous inter-connected structure, large specific surface area, high pore volume, and no loss of nitrogen content. HNGC-2 demonstrated an excellent rate capability of 62.8% at 20 A g⁻¹, outstanding stability of 96.1% following 5000 cycles and the assembled symmetric supercapcitor achieved 12.5 Wh kg⁻¹ at a 350 Wkg^-1 and 7.5 Wh kg⁻¹ at 3500 Wkg^-1. The novel method was also found to be effective for facilitating the electrochemical performance of commercial biomass active carbon. In addition, HNGC-2 was used for the photo-catalytic degradation of methylene blue and over 99% of methylene blue was successfully degraded under 25-min visible irradiation in the presence of potassium persulfate. The enhanced electrochemical performance and the excellent photo-catalytic performance of HNGC-2 indicated that porous carbon can be successfully activated using an appropriate oxidation strategy.

分层多孔氮掺杂二维碳（HNGC）是通过硫酸镁（MgSO ₄ ）和自合成的氮掺杂二维石墨烯类碳在氧气中温和温度的简单煅烧制备的。采用扫描电子显微镜、透射电子显微镜、X射线衍射、拉曼光谱、比表面积分析、X射线光电子显微镜和元素分析仪研究了MgSO4对制备的HNGC样品的形貌、结构和化学成分的影响。HNGC-2呈现出均匀的三维珊瑚状多孔互连结构，比表面积大，孔容大，不损失氮含量。HNGC-2 在 20 A g ^{-1下表现出 62.8% 的优异倍率能力}，在 5000 次循环后具有 96.1% 的出色稳定性，组装的对称超级电容器在 350 Wkg -1 时达到 12.5 Wh kg -1 ，^在3500 Wkg ^-1时达到7.5 Wh kg ^-1 。还发现该新方法可有效促进商业生物质活性炭的电化学性能。此外，HNGC-2 用于亚甲基蓝的光催化降解，在过硫酸钾存在下，25 分钟可见光照射下，99% 以上的亚甲基蓝被成功降解。HNGC-2增强的电化学性能和优异的光催化性能表明，使用适当的氧化策略可以成功地活化多孔碳。