| Facing the current environmental pollution and energy crisis,photocatalytic technology has gradually attracted widespread attention because of its green environmental protection,clean and efficient conversion of solar energy into chemical energy.The key to photocatalytic technology lies in the development and application of efficient photocatalysts.Copper bismuthate,as an inexpensive visible-light-driven semiconductor material,exhibits excellent catalytic performance in the fields of pollutant degradation and water splitting.Based on the CuBi2O4 semiconductor material,this paper explores the synthesis methods of preparing CuBi2O4 with different morphologies,and developsα-Fe2O3/CuBi2O4,CuBi2O4/P25 composite materials,and systematically studies its performance and mechanism in photocatalytic pollutant degradation,water splitting and hydrogen production.The specific content as follows:(1)CuBi2O4 semiconductor material was prepared by one-step hydrothermal method.By changing the conditions of the hydrothermal reaction(such as the ratio of water and ethanol in the precursor solution,the time and temperature of the hydrothermal reaction,etc.),CuBi2O4 materials with different morphologies such as rod-shaped,hemispherical,and butterfly-like were prepared.Using Congo red as a pollutant model,the photodegradation performance of CuBi2O4 catalysts with different morphologies was explored.The results show that the polarity of the precursor solution can effectively adjust the morphology of CuBi2O4 Among them,the bow-tie-like CuBi2O4 material showed good photocatalytic activity for the degradation of Congo red,and the degradation rate could reach 95.3%after 40 min of illumination.(2)A series of bowtie-like α-Fe2O3/CuBi2O4 composite photocatalysts with a series of component ratios were synthesized by hydrothermal method,and their degradation of rhodamine B(RhB)and p-nitrophenol(PNP)under visible light was studied.The effects of the composite catalyst components,the initial pH of the pollutant solution and other conditions on the photocatalytic activity were systematically investigated.The results show that the 7%Fe2O3/CuBi2O4 material exhibits the highest photodegradation efficiency in a weak alkaline environment.and the degradation efficiency of Rhodamine B(RhB)and p-nitrophenol(PNP)can reach 83.2%and 91.3%,respectively.after 50 min of illumination.At the same time.it can effectively degrade PNP and RhB mixed pollutants under natural light.The α-Fe2O3/CuBi2O4 heterojunction adopts the S-scheme carrier transport mode,which can effectively improve the separation efficiency of photogenerated charges;in a weak alkaline environment,the generation of a large amount of·OH in the photo-Fenton system improves the photocatalytic activity of the material.Under the synergistic influence of the above two factors,the degradation ability of the reaction system to pollutants is enhanced.(3)A series of Step-scheme(S-scheme)CuBi2O4/Na-P25 photocatalysts were synthesized through a facile hydrothermal method.CuBi2O4/Na-P25 photocatalyst(CBO/Na-P25)without co-catalyst exhibited the good photocatalytic performance for hydrogen evolution.H2 yield rate of the 7.5%CBO/Na-P25 sample achieved 2695.73μmol/gcat/h after 4 h illumination,which was more than 37.8,13.7 and above 100 times those of pure P25,Na-P25 and CuBi2O4.The band structure for the typical CuBi2O4/NaP25 was characterized by UV-vis reflectance spectroscopy and X-ray photoelectron spectroscopy.The band gap of P25 decreased by Na doping and the construction of CuBi2O4/Na-P25 heterojunction contributed to the efficient interfacial charge separation.Meanwhile,the S-scheme carrier transfer mechanism of CuBi2O4/Na-P25 heterojunction photocatalyst was verified by the experimental results under the different light wavelengths.. |
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