Metal-free g-C₃N₄ is always limited by low surface area, rapid charge recombination and limited visible light absorption. In this study, novel porous nitrogen self-doped g-C₃N₄ nanosheets were prepared by a combination of N self-doping and thermal exfoliation process. Compared to the bulk g-C₃N₄, N self-doped g-C₃N₄ nanosheets possessed a high specific surface area of 74.79 m² g⁻¹, enhanced visible light absorption, improved photogenerated electron-holes separation, and prolonged lifetime of photogenerated charge carriers. As a consequence, N self-doped g-C₃N₄ nanosheets exhibited higher photocatalytic activity for tetracycline (TC) degradation than that of bulk g-C₃N₄, N self-doped g-C₃N₄ and g-C₃N₄ nanosheets. It also exhibited remarkable stability and repeatability. The detailed photocatalytic mechanism was proposed. The midgap states created by N doping can significantly enlarge the visible light absorption, reduce the recombination and prolong the lifetime of photogenerated charge carries. The nanosheet construction can provide increased surface area, abundant active sites, short charge diffusion distance, fast separation and promoted redox abilities of photoexcited charge carries.

不含金属的gC ₃ N ₄始终受到表面积低，电荷快速复合和可见光吸收受限的限制。在这项研究中，通过结合氮自掺杂和热剥落工艺制备了新型的多孔氮自掺杂gC ₃ N ₄纳米片。与块状gC ₃ N _4相比，N自掺杂gC ₃ N ₄纳米片具有74.79 m ²  g ^-1的高比表面积，增强的可见光吸收，改进的光生电子-空穴分离和延长的光生电荷寿命运营商。结果，N个自掺杂的gC ₃N ₄纳米片对四环素（TC）的降解表现出比块状gC ₃ N ₄，N自掺杂gC ₃ N ₄和gC ₃ N ₄纳米片更高的光催化活性。它还显示出显着的稳定性和可重复性。提出了详细的光催化机理。N掺杂产生的中间能隙态可以显着增加可见光吸收，减少重组，并延长光生电荷携带的寿命。纳米片构造可提供增加的表面积，丰富的活性位点，短的电荷扩散距离，快速的分离和提高的光激发电荷载体的氧化还原能力。