Preparation And Photocatalytic Activity Of TiO₂ Nanotube Arrays Loaded With MnCo₂O_4.5

Water is the most important thing for life.However,with the intensification of industrial production,the expansion of population,and the plundering of natural resources,water resources have been severely polluted.Water pollution has become an environmental pollution problem that needs to be solved urgently.However,traditional water pollution treatment technologies have some limitations,so photocatalytic technology emerges.Titanium dioxide is a widely investigated semiconductor catalyst.Conventional wide band gap morphology of titanium dioxide is mainly composed of nanoparticles,nanowires and nanorods.However,these forms of catalysts have a disadvantage of being difficult to recycle and reuse.Although titanium dioxide has excellent photocatalytic properties,the problems of low quantum efficiency,high electron-hole recombination rate and low utilization of sunlight reduce its value in real applications.The modification of titanium dioxide is an effective method to solve these shortcomings.In this thesis,MnCo₂O_4.5 nanoparticles were deposited on the surface of titanium dioxide nanotube arrays in order to synthesis nanophotocatalyst with high recyclability.The anodization is a method for preparing titanium dioxide substrate?TiO₂ Nanotube Arrays,TiO₂ NAs?by etching a pretreated titanium substrate,and the method successfully solves the problem that the catalyst material is difficult to recover.The tube length,inner diameter and wall thickness of the TiO₂ nanotube arrays were controlled by changing the content of NH₄F and H₂O in the electrolyte,the oxidation voltage and the oxidation time.After optimizing,3 mass%NH₄F,2 v% H₂O ethylene glycol electrolyte,oxidation voltage 50 V and 1 h oxidation time were selected as the preparation conditions.The tubes length,inner diameter and wall thickness of prepared TiO₂nanotube arrays were 12?m,103 nm and 10 nm,respectively.Under ultraviolet light,the photocatalytic degradation performance was measured by degrading different organic?Component including methyl orange,rhodamine B,methylene blue,congo red and tetracycline?,and the degradation efficiency of tetracycline was 98.6% in 120 min.MnCo₂O_4.5 nanoparticles were deposited on the surface of TiO₂ NAs by a chemical bath deposition method.The amount of deposited MnCo₂O_4.5 nanoparticles was controlled by varying the deposition time.The morphology and structure of MnCo₂O_4.5 deposited TiO₂ NAs were measured by different characterization methods.The photocatalytic degradation of tetracycline was studied under the simulated sunlight.The degradation results showed that the best photocatalytic effect was obtained with the deposition time of 140 min.The efficiency of photocatalytic degradation of tetracycline was 93.1%in 120 min.The results measured by ICP and recycle experiment showed a good photocatalytic stability of as-prepared materials.Photoelectrochemical detection of materials further explained the reasons for its improvement in photocatalytic performance.The mechanism of photocatalytic degradation of tetracycline by MnCo₂O_4.5/TiO₂ NAs was further explained by free radical trapping experiments.