Preparation Of Ti₃C₂-derived Nitrogen-doped TiO₂@C Composite Catalyst And Study On Photo-fenton Degradation Performance Of Organic Pollutants In Water

The photo-Fenton technique is a method that uses light to enhance the activity of Fenton reaction.Photocatalytic materials are introduced into the traditional Fenton system,and the synergistic effect of Fenton reaction and photocatalytic reaction is used to remove organic pollutants in water.Although titanium dioxide（TiO₂）is known as the most promising environmentally friendly photocatalyst,it still has disadvantages such as low light utilization and low quantum efficiency.Based on this,this paper first uses the two-dimensional layered transition metal carbide Ti₃C₂as the carbon skeleton and uniform titanium source,and adopts the high-temperature calcination method to introduce nitrogen doping and carbon materials to prepare the modified TiO₂photocatalyst.Secondly,a variety of physical and chemical characterization methods were used to study their morphology,structure and photocatalytic performance of the prepared photocatalyst.Finally,the catalytic degradation performance of the photo-Fenton system under different conditions was explored.The main contents are as follows:1.Preparation of nitrogen-doped TiO₂@C@Fe₃O₄ and study on degradation performance of photo-Fenton organic systemThe N-TiO₂@C@Fe₃O₄ composite catalyst which can be separated by magnetic separation technology was synthesized by solvothermal method,and various characterization methods were used to prove that the two-dimensional layered composite catalyst is N-doped carbon-based composite material on N-doped TiO₂and Fe₃O₄hybrid.N-TiO₂@C@Fe₃O₄,as an excellent composite cocatalyst,greatly improves the decomposition efficiency of H₂O₂in homogeneous photo-Fenton system,and the dosage of H₂O₂and Fe²⁺is significantly reduced,then reduces operating costs.Rhodamine B（Rh B）and malachite green（MG）were selected as the organic dye research models.Under optimized conditions,the degradation efficiency of Rh B reached 96.5%within 300 s under visible light irradiation,which is much higher than that of traditional Fenton（43.5%）.And after 10 cycles,the catalyst still maintains stable structure and performance,and the degradation efficiency remains above 90%;under the same conditions,when Fenton reagent is only 1/4 of the Rh B system,MG（99.7%）can be completely completed within 600 s.Tetracycline hydrochloride（TC）and oxytetracycline hydrochloride（OTC）were selected as research models for pharmaceuticals and personal care products（PPCPs）.Under optimal conditions,the degradation efficiency of TC reached 90.0%within 60 minutes(（under the same conditions,the degradation efficiency of TC of traditional Fenton was only 14.7%）,and the OTC degradation efficiency is 86.8%.In summary,the photo-Fenton system constructed in this paper can efficiently degrade dyes and PPCPs in water.2.Preparation of nitrogen-doped TiO₂@C aerogel and study on degradation performance of photo-Fenton systemThe N-TiO₂@C aerogel composite catalyst with better catalytic activity is prepared by ethylene diamine（EDA）assisted self-assembly,which has a stable three-dimensional structure and a larger specific surface area.N-TiO₂@C aerogel tremendously increases the decomposition efficiency of H₂O₂in homogeneous photo-Fenton systems and significantly reduces the amount of Fenton reagent.OTC is selected as the research model of PPCPs.Under the optimal conditions,the degradation efficiency of OTC within 60 minutes is 90.2%.In addition,Rh B is selected as the research model for organic dyes.Under the best conditions,when visible light irradiation,the degradation efficiency of Rh B reaches 96.2%within 20 s,and it is almost completely degraded within 600 s（99.6%）.After 5 cycles,the catalyst is still maintaining a stable performance,and the degradation efficiency remains above 95%.The experimental results show that the active species in the photo-Fenton system to degrade Rh B include·O₂^-,·OH and h⁺.