g-C3N4/Bi2O2CO32D纳米片复合材料的制备及可见光催化性能研究

采用自组装和化学沉淀法分别制得两种可见光驱动复合材料石墨相氮化碳/碳酸氧铋(g-C_3N_4/Bi_2O_2CO_3).采用X射线衍射光谱(XRD),紫外可见光谱、扫描电镜(SEM)、N_2吸附、电化学阻抗谱(EIS)和X射线光电子能谱(XPS)等分析手段对制备的催化剂进行了表征.结果表明,制备方法对纳米复合材料的晶相、形态及光学性能没有影响,但是影响g-C_3N_4和Bi_2O_2CO_3之间的相互作用力,导致光生电子-空穴对的分离速率存在显著差异.以可见光驱动苯酚和罗丹明B的降解实验为探针反应检测催化剂的光催化性能.实验结果表明自组装法得到的异质结催化剂中相互作用力更强,催化效果最高.O_2-是罗丹明B降解反应的主要活性物种,染料的光敏化、Bi_2O_2CO_3与g-C_3N_4综合效应,导致光生载流子电荷分离效率更高.

Preparation and Photocatalytic Performance of g-C3 N4 Composites Hybridized with Bi2 O2 CO3 2D Nanosheets

Two types of g-C₃N₄/Bi₂O₂CO₃ 2D nanosheet composites were prepared by self-assembly and chemical precipitation. The obtained catalysts were well characterized by X-ray diffraction (XRD), UV-Vis spectroscopy, scanning electron microscopy (SEM), N₂ adsorption-desorption, electrochemical impedance spectra (EIS) and X-ray photoelectron spectroscopy (XPS) and applied to the photocatalytic degradation of organic compounds. The results showed that the synthetic methods slightly affect the crystal phase, morphology and optical property of the obtained composite products, but strongly influence the interaction between g-C₃N₄ and Bi₂O₂CO₃, resulting in an obvious difference in the separation rate of photogenerated electrons and holes. Their photocatalytic performances were investigated in visible-light-driven rhodamine B (RhB) and phenol degradation. The g-C₃N₄/Bi₂O₂CO₃ heterojunction composites prepared by self-assembly showed the better activity with stronger interaction and good photocataly-tic stability after three cycles. The ^·O₂^- radicals are confirmed responsibility for RhB visible-light-driven degradation. The obvious enhancement of the visible-light-driven catalytic performance is ascribed to the high charge-separation efficiency because of the multiple effects of photosensitive RhB, g-C₃N₄ and Bi₂O₂CO₃. The self-assembly method assisted by CTAB results in strong interaction between Bi₂O₂CO₃ 2D nanosheets and g-C₃N₄ layers facilitating tight contact and formation of a stable heterojunction composite.