| Photocatalytic technology as a green sustainable development technology has gradually become the main solution to solve the world's energy and pollution problems At present,it has been widely used in the fields of sewage treatment,purification of polluted air,and water-decomposition.As a semiconductor material,titanium dioxide(TiO2)has been studied a lot since Fujishima and Honda discovered in 1972 that it can decompose water under the irradiation of ultraviolet light.Due to its advantages such as low price,easy to obtain,and excellent corrosion resistance,a variety of morphologies and multi-component TiO2-based composite catalysts have emerged endlessly,and they are widely used in various fields of photocatalysis.However,due to no visible absorption capacity,poor quantum efficiency and the high recombination rate of photogenerated carriers of TiO2 itself,the practical application of TiO2 has been greatly limited.In this paper,the TiO2 nanofibers prepared by electrospinning are used as a matrix,and the zero-dimensional(0D)/one-dimensional(1D)and one-dimensional(1D)/two-dimensional(2D)composite photocatalyst to achieve effective separation of photogenerated carriers in the photocatalytic process,thereby improving the photocatalytic efficiency of the catalyst.The main research results are as follows(1)The 0D/1D Ag3PO4/TiO2 nanocomposite was obtained by hydrothermal method combined with electrostatic self-assembly.Ag3PO4 nanoparticles in the obtained composite material were evenly distributed on the surface of TiO2 nanofibers,with an average particle diameter of 22 nm.The stable contact surface between 0D Ag3PO4 NPs and 1D TiO2 NFs makes the prepared composite material have good photoelectric performance and excellent photogenerated carriers separation ability Finally,photocatalytic degradation of organic pollutants under full-spectrum light irradiation and pure visible light irradiation was evaluated.The photocatalytic performance of the TiO2/Ag3PO4 nanocomposites was evaluated and possible photocatalytic mechanisms were analyzed in detail.The results show that when the concentrations of pollutants rhodamine B,methylene blue and methyl orange are 10 mg/L and the catalyst content is 10 mg/L,it only takes 5,2.5 and 3.5 minutes to degrade the aqueous solution of pollutants under visible light,respectively.When the concentration of aqueous solution of pollutant phenol is 50 mg/L and the catalyst content is 10 mg/L,it only takes 15 minutes to reduce the concentration of the pollutant by 60%.When the concentration of aqueous solution of pollutant tetracycline hydrochloride is 10 mg/L,it takes only 8 minutes to reduce the concentration of pollutants by 80%.At the same time,similar results were obtained under full spectrum light irradiation.The photocatalytic reaction mechanism shows that the main role of photocatalytic materials in the photocatalytic process is hydroxyl radicals and superoxide negative radicals,and the fundamental reason for the improvement of photocatalytic performance is attributed to the close contact between 0D Ag3PO4 and 1D TiO2,it leads to the formation of type ? heterojunction,which ultimately greatly promotes the separation efficiency of photogenerated carriers,thus enhancing the photocatalytic activity of the composite material(2)1D/2D TiO2/MXene composite materials were prepared by electrostatic self-assembly.The results show that a tight contact surface is formed between Ti3C2 and TiO2,the electron hole transport resistance inside the material is less than the two single phases.The photocurrent intensity and the separation efficiency of photogenerated carriers of the composite is stronger than the two single phases.When the content of Ti3C2 is 3 wt.%,the composite material has the best photocatalytic hydrogen production efficiency.Compared with the pure phase TiO2(1.831 mmol·h-1·g-1),the photocatalytic reaction efficiency is imporved by 3.8 times(6.979 mmol·h-1·g-1). |
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