The Construction Of 3DOM-TiO₂ Composites And Their Photocatalysis/electrochemical Energy Storage Performance

Titanium dioxide(TiO₂)materials are widely used as industrial products in the fields of dyestuff,food,and environmental protection.In the field of scientific research,TiO₂has been a hot material for research in the field of catalysis including non-homogeneous catalysis,electrocatalysis and photocatalysis,especially photocatalysis,because of its unique semiconductor properties,low cost of raw materials and good environmental compatibility.In the research of photocatalytic materials,the energy band structure of TiO₂has caused its inherent defects such as easy compounding of photogenerated electrons and holes and difficulty in using visible light region,thus limiting the industrial application of TiO₂as a single material in the field of photocatalysis.In order to solve the above problems,scientific researchers have conducted a lot of research around TiO₂.Among them,three-dimensional ordered macroporous titanium dioxide(3DOM-TiO₂)materials exhibit unique properties that are superior to other forms of TiO₂due to their high specific surface area and unique slow photon effect.In this thesis,3DOM-TiO₂carrier materials synthesized in the laboratory were used as carrier materials,and two different modification paths,surface loading and bulk phase doping,were used to synthesize3DOM-TiO₂carrier materials morphologically and controllably with carbon and nitrogen layers(NC),molybdenum disulfide(MoS₂),gold nanoparticles(AuNPs)and copper sulfide(CuS)materials as modification species,respectively,and from photocatalytic,In this dissertation,four aspects of photocatalysis and electrochemical energy storage were investigated.In this dissertation,four main areas of research have been carried out as follows.(1)Dopamine hydrochloride(PDA)was used as the precursor of carbon and nitrogen materials,and the carbon and nitrogen(NC)layer was modified on the surface of 3DOM-TiO₂materials and the inner wall of the pore cavity by high-temperature calcination treatment.Through a series of characterization tests such as XRD,SEM and TEM,it was found that by controlling the amount of PDA,the NC"coating layer"of different thicknesses could be loaded on the inner surface of 3DOM-TiO₂material in a controlled manner.The experimental results of photocatalytic degradation of methylene blue(MB)dye show that the3DOM-TiO₂/NC composite can achieve 98%degradation rate of MB after 30 minutes of visible light irradiation and 90%degradation rate of the dye after four cycles.(2)Based on the 3DOM-TiO₂/NC composites in part(1)of the research work,3DOM-TiO₂/NC nanocomposites modified with multilayer MoS₂nanosheets were further synthesized by hydrothermal method.The results of characterization by XRD,SEM and TEM showed that the MoS₂sheet layers were loaded on 3DOM-TiO₂/NC.The test results of battery energy storage on the composite showed that it had a high discharge capacity of 610 m A·h·g^-1at 100 m A·g^-1and the capacity retention rate was above 98%after 180 cycles of charging and discharging.(3)For the first time,a series of AuNPs@3DOM-TiO₂composites were obtained by a modified hard template method with bulk phase doping.Comparing the conventional 3DOM-TiO₂surface-loaded AuNPs samples with the same loading,it was found that the bulk phase doping could obtain better visible light degradation activity.Further,the effects of different Au loadings on the photocatalytic performance of the composites were investigated and their photocatalytic mechanisms were preliminarily elucidated by radical trapping experiments,which provide useful references for the research direction of noble metal modification of3DOM-TiO₂series materials.(4)The 3DOM-TiO₂/CuS composites were prepared by one-step hydrothermal treatment with 3DOM-TiO₂as the carrier,and the samples were characterized and analyzed by XRD,SEM,EIS and DRS characterization methods.3DOM-TiO₂/CuS composites exhibited excellent photocatalytic performance.The degradation rate of MB dye reached 98%after 180 min of visible light irradiation,and was able to maintain 80%after four cycles.