Preparation And Photocatalytic Performance Of BiOCl Composites Modified By MOFs

Water is the source of life,water pollution not only damages people’s lives and health but also the ecological environment,and effective treatment of water pollution has become urgent.As an inexhaustible energy source,solar energy has played a key role in the evolutionary history of human life.Among the many strategies to deal with water pollution,photocatalysis stands out for its efficient use of solar energy.Nowadays,the role of photocatalysis in various disciplines such as green energy,chemical synthesis,environmental technology and medicine is becoming irreplaceable.Photocatalysis is a technology that uses chemical methods to degrade pollutants in water without polluting the environment twice,and therefore has a very promising future in environmental remediation.The design and preparation of appropriate heterojunction mode photocatalysts is an effective means to improve photocatalytic performance.The main work of this thesis is summarized as follows:1.MOF-902（Ti）/BiOCl heterojunctions were constructed using MOF-902（Ti）and BiOCl,which effectively degraded the antibiotic tetracycline（TC）under visible light irradiation.The photodegradation ability of MOF-902（Ti）/BiOCl was higher than that of MOF-902（Ti）and BiOCl.Various characterizations such as XRD,XPS,SEM and TEM verified the formation of MOF-902（Ti）/BiOCl heterojunctions significantly improved the visible light response,increased the specific surface area and pore volume,effectively promoted the separation and transfer of electron-hole pairs,and finally improved the photocatalytic performance of MOF-902（Ti）/BiOCl heterojunctions.Under visible light irradiation,78%of tetracycline was degraded by MOF-902（Ti）/BiOCl heterojunction within 40 min,and the reaction rate constant was 0.02968 min^-1.Efficient active species capture experiments showed that-O₂^-,e^-and h⁺jointly participated in the photodegradation of TC.A possible mechanism to enhance the photocatalytic activity of MOF-902（Ti）/BiOCl heterojunctions is proposed.2.Cu-MOF/BiOCl heterojunction photocatalysts were constructed using Cu-MOF and BiOCl.Subsequently,the structure,composition,morphology and specific surface area of the composites were investigated.Compared with BiOCl,the composites have a larger specific surface area and possess more active sites.The photoelectrochemical properties of the composites were analyzed by transient photocurrent response,Mott-Schottky curves,electrochemical impedance spectroscopy（EIS）and PL spectroscopy.Compared with BiOCl,the Cu-MOF/BiOCl composites effectively promoted the separation and transfer of electron-hole pairs.Under visible light irradiation,the degradation rate of Rhodamine B（Rh B）by Cu-MOF/BiOCl heterojunction can reach 98%within 40 min,and the reaction rate constant is0.08697 min^-1.the photodegradation ability of Cu-MOF/BiOCl was higher than that of Cu-MOF and BiOCl.the effects of key parameters such as the amount of photocatalyst,the concentration of organic pollutants and p H on the photocatalytic performance were also investigated.The results of cycling experiments showed that the Cu-MOF/BiOCl heterojunction had good cycling stability.The active substance capture experiments proved that-O₂^-,e^-and h⁺played a major role in the photocatalytic degradation process.Finally,the mechanism of visible light degradation of Rh B by Cu-MOF/BiOCl heterojunction photocatalysts was thoroughly investigated.