氯氧化铋/氧化亚铜复合材料的制备及其可见光催化性能

通过水热法成功制备了BiOCl/Cu₂O 复合材料, 是一种良好的可见光响应的光催化剂。通过X 射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-vis) 和电化学阻抗谱(EIS) 等分析方法对BiOCl/Cu₂O 复合材料进行表征分析。以酸性橙(AO7) 为目标污染物进行光催化降解实验, 探究了BiOCl/Cu₂O 复合材料的光催化性能和降解机制。XRD 结果表明, 随着BiOCl 含量的增多, BiOCl 的衍射强度逐渐上升。SEM 结果表明, BiOCl 小纳米片附着在相对较大的八面体Cu₂O 表面形成复合结构。通过UV-vis 和EIS 分析结果可知, 复合材料的带隙相较于Cu₂O 略微增大但其阻抗明显变小。降解实验结果表明, 质量比为3 : 5 的BiOCl/Cu₂O 复合材料在90 min时的可见光催化降解率(56.8%) 明显高于Cu₂O 的降解率(26.3%), 其降解速率常数(0.009 3 min^-1) 是纯Cu₂O(0.003 3 min^-1) 的2.8 倍。自由基捕获实验表明BiOCl/Cu₂O 复合材料光催化过程中起主要作用的活性物种是超氧自由基(·O_{2^- )。6 次循环降解实验后光催化剂BiOCl/Cu2O(3 : 5) 对AO7 的降解率仍可达到48.3%。BiOCl 与Cu2O形成的异质结构在一定程度上降低了表面转移电阻, 加快了光催化过程中光生电子的转移速率, 提高了光生电子和空穴的分离率, 增强了光催化效果。}

Preparation of Bismuth Chloride Oxide/Cuprous Oxide Composites and Their Visible Light Catalytic Properties

BiOCl/Cu₂O composites were successfully prepared by hydrothermal method, which is a good visible light responsive photocatalyst. The BiOCl/Cu₂O composites were characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis) and electrochemical impedance spectroscopy (EIS). Photocatalytic degradation experiments were carried out with acid orange (AO7) as the target pollutant to investigate the photocatalytic performance and degradation mechanism of BiOCl/Cu₂O composites. The XRD results show that the diffraction intensity of BiOCl gradually increases with the increase of BiOCl content. SEM results show that BiOCl small nanosheets are attached to the relatively large octahedral Cu₂O surface to form a composite structure. The results of UV-vis and EIS analyses show that the band gap of the composites is slightly increased compared to Cu₂O but its impedance is significantly smaller. The results of the degradation experiments show that the visible photocatalytic degradation rate of BiOCl/Cu₂O composites with a mass ratio of 3 : 5 at 90 min (56.8%) is significantly higher than that of Cu₂O (26.3%), and its degradation rate constant (0.009 3 min^-1) is 2.8 times higher than that of pure Cu₂O (0.003 3 min^-1). Free radical trapping experiments show that the active species playing a major role in the photocatalytic process of BiOCl/Cu₂O composites is superoxide radicals (·O₂^-). The degradation rate of AO7 by the photocatalyst BiOCl/Cu₂O (3 : 5) could still reach 48.3% after six cyclic degradation experiments. The heterogeneous structure formed by BiOCl and Cu₂O reduces the surface transfer resistance to a certain extent, accelerates the transfer rate of photogenerated electrons in the photocatalytic process, improves the separation rate of photogenerated electrons and holes, and enhances the photocatalytic effect.