Mo源改性石墨相氮化碳(g-C3N4)活化过一硫酸盐可见光降解罗丹明B的性能研究

分别以钼酸钠（MA）和乙酰丙酮钼（MC）作为钼（Mo）源，采用热聚合法合成不同类型Mo-C₃N₄材料（MACN和MCCN），并通过XRD、SEM、XPS、UV-Vis DRS等表征技术探究不同Mo源的引入对g-C₃N₄晶体结构和光学性质的影响.结果表明，Mo的引入增大了g-C₃N₄的晶格间距，以MC为Mo源合成的MCCN催化剂具有更大的比表面积、更宽的可见光响应范围和更低的能带宽度.将所合成的催化剂应用于耦合过一硫酸盐（PMS）可见光催化降解罗丹明B （RhB）研究，发现在催化剂浓度为0.5 g·L^-1、PMS浓度为1 mmol·L^-1、罗丹明B浓度为10 mg·L^-1的条件下，MCCN-4/PMS/Vis催化体系在25 min内对RhB的降解率高达94.1%，分别是MCCN-4/Vis和单独PMS催化体系的5.6和19.2倍，并且RhB光催化降解过程符合一级动力学方程.为进一步探索MCCN/PMS/可见光（Vis）催化体系的最佳工艺条件，系统考察了Mo的掺杂量、催化剂投加量、PMS浓度、污染物浓度、pH值等实际因素对RhB降解效果的影响.同时，循环实验表明，MCCN-4复合催化剂具有良好的稳定性和可重复性，3次循环之后仍保持89.1%的RhB降解率.此外，捕获实验和电子自旋共振测试（ESR）结果表明，在MCCN/PMS/Vis催化体系下，光生空穴（h⁺）和超氧自由基（·O₂^-）作为主要活性物种参与了RhB的降解.

Efficient activation of peroxymonosulfate by Mo source modified graphite phase carbon nitride (g-C3N4) for the degradation of Rhodamine B under visible light

Different sources of molybdenum including sodium molybdate (MA) and molybdenum acetylacetonate (MC) were used to modify graphite phase carbon nitride (g-C₃N₄) to obtain a series of Mo-C₃N₄ catalysts (MACN and MCCN) by the thermal polymerization method. In order to study the effect of Mo on the crystal structure and optical properties of the materials, different characterization, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), were condcuted. The result showed that doping with Mo increases the lattice spacing of g-C₃N₄. Besides, a series of MCCN catalysts have a larger specific surface area, wider visible light response range and lower energy band gap. In this study, the MCCN-4/Vis/PMS system showed the best catalytic activity for the degradation of rhodamine B (RhB), with a removal of over 94% (catalyst]=0.5 g·L^-1, PMS]=1 mmol·L^-1, RhB]=10 mg·L^-1) within 25 min. It was 5.6 and 19.2 fold higher than that of MCCN-4/Vis and independent PMS catalysis system. The photocatalytic degradation reaction of RhB in different systems followed the first-order kinetic equation. To further explore the optimal catalytic process conditions of MCCN-4/PMS/Vis system, the effects of different parameters including catalyst loading, catalyst dosage, the concentration of PMS and RhB, and initial solution pH on its catalytic activity were also examined. Additionally, MCCN-4 showed good stability and repeatability, which removed 89.1% of RhB after three cycles. Based on the results of quenching experiment and electron spin resonance test (ESR), it can be found that photo-generated holes (h⁺) and superoxide radicals (·O₂^-) were the main active species for RhB degradation in the MCCN/PMS/Vis catalytic system.