Preparation Of Highly Active TiO₂ Composite Catalysts And Their Photocatalytic Performance

As a research hot spot in the field of photocatalysis,TiO2 nanomaterials have the advantages of stable chemical properties,high photocatalytic activity.However,TiO2 nanomaterials have the defects of large bandgap and small spectral response range.The composite semiconductor method promotes the transport and separation of photogenerated carriers between semiconductors of different energy levels,and further enhances the photocatalytic activity.By compounding TiO2 nanomaterials with other semiconductor materials,photoelectron-hole recombination can be controlled.In this paper,TiO2 was modified by compound semiconductor method,g-C3N4/TiO2 composite catalyst was synthesized by high-temperature calcination method,and the Mo S2/TiO2 composite catalyst was synthesized by ultrasonic method.The nano-flower Mo S2/TiO2 composite catalyst was synthesized by hydrothermal method.Rhodamine B and phenol were used as target degradants to investigate the photocatalytic activity of composite catalysts,and the degradation mechanism and photocatalytic mechanism of phenol were investigated.X-ray powder diffraction(XRD),specific surface area measurement(BET),Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM)were used to characterize the composite catalysts.The results show that:(1)TiO2 nanoparticles prepared by direct hydrolysis method are spherical,the g-C3N4 synthesized by precursor urea is in a thin-film network structure,and the g-C3N4/TiO2 composite catalyst has a large specific surface area(60.7 m2·g-1);g-C3N4/TiO2 composite catalyst has good catalytic activity for both RhB and phenol;g-C3N4/TiO2 photocatalytic degradation process,the introduction of g-C3N4 can narrow the band gap,promote photoelectron Transferred,effectively inhibited the recombination of photoelectrons and holes;(2)The ultrasonically exfoliated Mo S2 lamellar structure exhibited a flake-like structure and was homogeneously mixed with the TiO2 nanoparticle in two phases;the TiO2 in the Mo S2/TiO2 composite catalyst was anatase crystal structure,Mo S2 crystal surface of a single layer of Mo S2;In the process of photocatalytic degradation of RhB,flake Mo S2 has a significant adsorption effect on RhB;27% Mo S2 loading of Mo S2/TiO2 photocatalytic is best;Mo S2 layer has rich interface and edge defects,improves the utilization rate of photoelectron,and provides a newcatalytic active center for the degradation reaction;(3)Mo S2 produced by using ammonium molybdate as a precursor has a good morphology and consists of small pieces.Combination into flowers,uniform size;combined with XRD crystal structure analysis and XPS elemental analysis to further confirm the formation of Mo S2;in the photocatalytic degradation of RhB reaction,nano-flowering Mo S2 has a higher adsorption and removal effect of RhB,when the Mo S2 loading is 0.5%,Mo S2/TiO2 nanoflower composite catalyst has the best catalytic effect on RhB.