Preparation Of BiOI/g-C₃N₄ Composites And Research To Their Photocatalytic Performance

In today’s society,environmental pollution is very serious,and it is one of the major challenges facing sustainable development.Photocatalytic technology has become an effective method to solve current environmental pollution problems due to its advantages of green environmental protection,no secondary pollution and recyclable catalysts.As a type of non-toxic,stable,and strong absorption to visible light,the composite photocatalyst based on BiOI has gradually attracted people’s attention.In this thesis,combining the current research hotspots,BiOI and g-C₃N₄ with different morphologies are combined to prepare a composite photocatalyst with their advantages,which provides a theoretical basis and experimental reference for further theoretical research and practical application in related fields.The specific contents are as follows:（1）The 2D/2D BiOI/g-C₃N₄（BiOI/CN-7%,BiOI/CN-15%,BiOI/CN-30%,BiOI/CN-50%and BiOI/CN-60%）sheet composite photocatalysts with different ratios were constructed by solvothermal method.XRD,XPS,FTIR,SEM and TEM analysis proved that the composite process did not cause changes in the structure and morphology of BiOI and g-C₃N₄;Optical and electrochemical performance analysis showed that the introduction g-C₃N₄ sheets improved the separation efficiency of photogenerted electron-hole pairs of BiOI/g-C₃N₄.Compared with other as-prepared photocatalysts,the BiOI/CN-50%photocatalyst exhibited the best photocatalytic performance.Under visible light,it can degrade 100%of TC in 120 min,and 40.91%of 4-CP in 240 min.The results of active species capture experiments and ESR measurement indicated that·OH,·O₂^-,and h⁺were the main active species,and a possible photocatalytic degradation mechanism was proposed.（2）The 2D/3D BiOI/g-C₃N₄（BiOI/CN-0.5,BiOI/CN-1,BiOI/CN-3 and BiOI/CN-7）tubular composite photocatalyst with excellent photocatalytic performance was prepared by solvothermal method.XRD,XPS,FTIR,SEM and TEM analysis proved that the composite process did not cause changes in the structure and morphology of BiOI and g-C₃N₄.BET,PL and electrochemical performance analysis indicated the introduction of g-C₃N₄ can increase specific surface area,visible light response range and the separation efficiency of photogenerated electron-hole pairs of BiOI/g-C₃N₄ composite.Under visible light,it degraded86.98%of TC in 90 min,and 68.95%of 4-CP in 240 min.Moreover,the catalyst had high stability.The results of active species capture experiments and ESR measurement implyed that·OH,·O₂^-,and h⁺were the main active species,and a possible photocatalytic degradation mechanism was revealed.