Ag3PO4量子点/石墨相氮化碳纳米片复合光催化剂的制备及其对苯甲醇选择性氧化活性

以热氧化剥离法得到的超薄石墨相氮化碳(g-C₃N₄)纳米片为载体,首次在室温条件下,制备了系列Ag₃PO₄量子点/g-C₃N₄纳米片复合光催化剂;通过透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)、荧光光谱(PL),对复合光催化剂的形貌、结构和光学性质进行了表征,考察了系列光催化剂对苯甲醇的光催化选择性氧化性能。 结果表明,粒径为3~5 nm Ag₃PO₄颗粒均匀分散g-C₃N₄纳米片上,结晶度良好。 以乙腈为溶剂时,当m(Ag₃PO₄)/m(g-C₃N₄)=0.6时,苯甲醇具有32.1%的最大转化率,对产物苯甲醛具有90%的最高选择性;活性物种捕捉实验结果表明,该催化氧化反应的主要活性物是光生空穴的氧化作用,能带计算结果表明,该复合催化剂结构具有合适的苯甲醇的氧化电位而选择性生成苯甲醛。

Preparation of Ag3PO4 Quantum Dots/g-C3N4 Nanosheet Composite Photocatalysts and Its Activity for Selective Oxidation of Benzyl Alcohol

In this paper, a series of Ag₃PO₄ quantum dots/g-C₃N₄ nanosheet composite photocatalysts was prepared at room temperature for the first time with the ultrathin g-C₃N₄ nanosheet exfoliated by thermal oxidation as the support. The morphology, structure and optical properties of the photocatalysts were characterized by transmission electron microscopy(TEM), high resolution TEM(HRTEM), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy analysis (FT-IR), ultraviolet-visible diffuse-reflectance spectroscopy (UV-Vis DRS), photoluminescence spectroscopy (PL) techniques. The photocatalytic selective oxidation of benzyl alcohol was investigated. The results show that quantum dots of well-crystallized Ag₃PO₄ with the particle size of 3~5 nm are homogeneously dispersed on the g-C₃N₄ nanosheet. For the photocatalysts with the mass ratio of 0.6 Ag₃PO₄ to g-C₃N₄ in acetonitrile, the maximum conversion of benzyl alcohol is 32.1%, and the highest selectivity of benzaldehyde is 90%. The results of active species capture experiment show that the main active species of photogenerated hole are responsible for the selective oxidation. The results of energy band calculation show that the composite catalyst has a suitable oxidation potential for benzyl alcohol into benzaldehyde.