Construction Of Bi/g-C₃N₄/BiOBrO₃ Composite By Coupling With SPR Effect Of Bi With G-C₃N₄ For The Degradation Of Aldehydes

Aldehyde pollutants from decoration and industrial sewage have caused serious damage to the environment and human health.In order to solve the problem of low purification efficiency and secondary pollution existing in the existing purification technology,the catalytic degradation of aldehydes pollutants by g-C₃N₄/BiOBrO₃coupling Bi plasma resonance purification materials was studied in this article.G-C₃N₄/BiOBrO₃ heterojunction was prepared by hydrothermal method,and Bi/g-C₃N₄/BiOBrO₃ composite was constructed by surface plasma effect(SPR)of non-noble metal Bi coupled with g-C₃N₄/BiOBrO₃ heterostructure.The effects of the composition and structure of Z-type heterojunction on the degradation activity and degradation stability of aldehydes were investigated.The effect of Bi surface plasma effect on the catalytic activity of g-C₃N₄/BiOBrO₃heterojunction was investigated,and the degradation efficiency of the composites for aldehyde pollutants was investigated.The purification efficiency of formaldehyde in waterborne coatings was studied by adding purification materials to the coatings.The photocatalytic mechanism of g-C₃N₄/BiOBrO₃ heterojunction and Bi/g-C₃N₄/BiOBrO₃ composites was analyzed using density functional theory(DFT).Specific research contents and conclusions were as follows:(1)The layered multipolarization nanostructured BiOBrO₃ and g-C₃N₄ were constructed with heterostructures.X-ray diffraction(XRD),Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),Ultraviolet-visible spectroscopy(UV-vis)and Electrochemical impedance spectroscopy(EIS)were used to study the chemical structure and light absorption properties of heterojunction.The degradation of acetaldehyde by g-C₃N₄/BiOBrO₃ heterojunction at room temperature was tested.It was found that the adsorption efficiency of acetaldehyde by 50wt.%g-C₃N₄/BiOBrO₃ heterojunction was 33%,that was,the mass ratio of g-C₃N₄to BiOBrO₃ in 50wt.%g-C₃N₄/BiOBrO₃ heterojunction was 0.5:1 and the degradation efficiency of acetaldehyde reached 71%within 180 min.The capture experiment of active substances showed that the main active substances in the degradation process were superoxide radical(·O^2-)and hydroxyl radical(·OH).By studying the electron transport direction inside g-C₃N₄ and BiOBrO₃,it was found that the electron transport mode between g-C₃N₄ and BiOBrO₃,which was in line with the Z-type heterojunction,has good adsorption and photocatalytic degradation effect on acetaldehyde.(2)Bi/g-C₃N₄/BiOBrO₃ composites were prepared by ultrasonic synthesis method.The obvious red shift of the light absorption of the composites indicates that the light absorption capacity was enhanced.It has a large specific surface area and more reactive active sites.The optimal doping mass ratio of 60wt.%,that was,the mass ratio of Bi elemental substance to g-C₃N₄/BiOBrO₃ heterojunction in 60wt.%Bi/g-C₃N₄/BiOBrO₃ composite material was 0.6:1.At room temperature,the degradation efficiency of acetaldehyde reached 92%in 180 min,and the degradation efficiency of 60wt.%Bi/g-C₃N₄/BiOBrO₃ composite was about 1.3 times higher than that of 50wt.%g-C₃N₄/BiOBrO₃ heterobond for acetaldehyde.The charge transfer inside the composite material was theoretically analyzed by density functional calculation,and the electron transport direction inside the Bi/g-C₃N₄/BiOBrO₃composite material was obtained.The plasma effect of Bi metal injected hot electrons into the conduction band(CB)of g-C₃N₄,resulting in the electron enrichment state of CB,and the valence band(VB)of BiOBrO₃ accumulated a large amount of h⁺,resulting in the generation of more active substances,thus improving the catalytic activity and degradation efficiency.The catalytic activity of g-C₃N₄/BiOBrO₃heterojunction was stimulated.The mechanism of Bi/g-C₃N₄/BiOBrO₃ was studied from the perspective of combining theory and experiment,and the effective adsorption and degradation mechanism of aldehyde pollutants was revealed.(3)The 60wt.%Bi/g-C₃N₄/BiOBrO₃ composite prepared under optimized conditions was dispersed in a mixed solution of polyethylene glycol(3 m L)?glycerol(3 m L)?propanediol butyl ether(1.5 m L)?deionized water(5 m L).According to the best formulation,composite materials with different mass ratios were added to commercial waterborne coatings to study the formaldehyde adsorption and degradation properties of coatings.By comparing its adsorption and degradation performance with that of commercial Dulux clean flavor coatings,it was found that the adsorption and degradation efficiency of self-made purification water-based coatings was at least 20%higher than that of commercial water-based coatings.The influence of the amount of composite material in the coating on the formaldehyde adsorption and degradation efficiency was discussed.It was shown that the best formaldehyde adsorption and degradation efficiency was achieved when the amount of catalyst was 14wt.%,and the degradation efficiency was 50%within 12 h.Within60 days,the degradation efficiency of formaldehyde was 60%.The results show that the doping of composite materials can improve the purification ability of waterborne coatings,and the purification coatings have the advantage of being clean and can be used for a long time without secondary pollution.This study provided a new strategy for indoor pollutant control.The results provided an experimental basis for the practical application of Bi/g-C₃N₄/BiOBrO₃ composite material and its wall coatings in the treatment of aldehyde pollutants.