In this study, nitrogen-deficient graphitic carbon nitride (M-LS-g-C3N4) with a mesoporous structure and a large specific surface area was obtained by calcination after melt pretreatment using urea as a precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-Vis, ESR and photoluminescence (PL) were used to characterize the structure, morphology and optical performance of the samples. The TEM results showed the formation of a mesoporous structure on the 0.1[Formula: see text]M-LS-g-C3N4 surface. The porous structure led to an increase in the specific surface area from 41.5[Formula: see text]m2/g to 124.3[Formula: see text]m2/g. The UV-Vis results showed that nitrogen vacancies generated during the modification process reduced the band gap of g-C3N4 and improved the visible light absorption. The PL spectra showed that the nitrogen defects promoted the separation of photogenerated electron–hole pairs. In the visible light degradation of methyl orange (MO), the reaction rate constant of 0.1[Formula: see text]M-LS-g-C3N4 reached 0.0086[Formula: see text][Formula: see text], which was 5.05 times that of pure g-C3N4. Superoxide radicals and photogenerated holes were found to be the main active species in the reaction system. This study provides an efficient, green and convenient means of preparing graphitic carbon nitride with a large specific surface area.

中文翻译：

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熔融预处理制备大比表面积缺氮石墨氮化碳及其光催化性能

在这项研究中，缺氮石墨氮化碳（M-LS-gC3ñ4) 以尿素为前驱体，经熔融预处理后煅烧，得到具有介孔结构和大比表面积的材料。X 射线衍射 (XRD)、透射电子显微镜 (TEM)、N2采用吸附、X射线光电子能谱(XPS)、紫外-可见光、ESR和光致发光(PL)表征样品的结构、形貌和光学性能。TEM结果表明在0.1[公式：见正文]M-LS-gC上形成了介孔结构3ñ4表面。多孔结构导致比表面积从 41.5[公式：见正文]m2/g 到 124.3[公式：见正文]m2/G。UV-Vis 结果表明，改性过程中产生的氮空位降低了 gC 的带隙。3ñ4并改善可见光吸收。PL光谱表明氮缺陷促进了光生电子-空穴对的分离。在可见光下降解甲基橙（MO），反应速率常数为0.1[公式：见正文]M-LS-gC3ñ4达到0.0086[公式：见文][公式：见文]，是纯gC的5.05倍3ñ4. 发现超氧自由基和光生空穴是反应体系中的主要活性物质。本研究为制备大比表面积的石墨氮化碳提供了一种高效、绿色、便捷的方法。