Study On The Performance Of N-TiO₂-based Composite Catalysts For Photocatalysis-fenton Degradation Of Rhodamine B

The issue of water pollution has become more and more severe with the development of industry.Traditional methods of sewage treatment are no longer sufficient to deal with more complex and diverse pollutants,therefore,the exploitation and utilization of efficient and environmentally friendly technologies for sewage treatment is the focus of the problem.Photocatalysis-Fenton technology combines photocatalytic oxidation technology and Fenton oxidation technology,which is a green and efficient technical means and can be widely used in the field of degrading pollutants.Among various semiconductor photocatalytic materials,titanium dioxide（TiO₂）has become one of the preferred semiconductor materials in the field of photocatalysis due to its low cost,stable structure and excellent optical properties,and has been widely applied and studied.However,TiO₂,with a wide band gap（3.2 e V）,can only absorb ultraviolet light,while most of the composition of sunlight is visible light,leading to the fact that TiO₂ alone cannot be effectively excited by sunlight,so the inefficient utilization of sunlight restricts the practical application of TiO₂.In addition,TiO₂ has the disadvantage of high photogenerated charge complexation rate,which causes the number of effective electrons-hole that can play a role to be reduced and further inhibits its photocatalytic performance.Therefore,we achieve the absorption of visible light through N-doping of TiO₂.And on the basis of N-TiO₂,we construct a photocatalysis-Fenton system by compounding with Fenton reagent with excellent electron transfer performance to realize the efficient degradation of organic pollutants.Furthermore,in order to address the problems of low utilization of visible light and poor practical applicability of the above materials,the noble metal loading method is applied to achieve highly efficient degradation of organic pollutants under visible light.The Surface Photovoltage Technique and Transient Photovoltage Technique are employed to characterize the photogenerated charge behavior of the composites,and the connection between photogenerated charge and degradation performance is deeply investigated.The specific work is as follows:1.N-TiO₂/Mn-HPMo photocatalysis-Fenton composite catalysts were synthesized by hydrothermal and acid impregnation methods,and applied to the degradation of Rhodamine B solution under UV-vis light.It was demonstrated by UV-vis diffuse reflectance spectroscopy（UV-vis DRS）that the N doping broadened the light absorption range of TiO₂ to the visible region.The photogenerated charge behavior between the catalyst surface and interface was characterized by Surface Photovoltage Technique and Transient Photovoltage Technique,and it was exhibited that Mn-HPMo could transfer the photogenerated electrons of N-TiO₂ to achieve the effective separation of photogenerated electrons-hole.The degradation mechanism of N-TiO₂/Mn-HPMo for the degradation of Rh B was thoroughly investigated.2.N-TiO₂/Mn-HPMo/Ag ternary composite catalysts were constructed utilizing photoreduction method and applied to the degradation of Rhodamine B solution under visible light.It was verified using UV-vis diffuse reflectance spectroscopy（UV-vis DRS）that the Ag deposition could enable significantly enhanced visible light absorption,and the characterization by Surface Photovoltage Technique demonstrated that the Ag loading could increase the photogenerated charge separation efficiency and provide more photogenerated electrons to participate in the photocatalysis-Fenton reaction.This part of the work provides efficient catalysts that are conducive for environmental remediation under visible light.