Study On The Structure Regulation Of Black Hexagonal Zinc Oxide And The Preparation Of Its Assembly And Its Photocatalytic Performance

The excellent optical,physical,and chemical properties of ZnO have caused widespread concern,and have prompted ZnO to be widely used as a photocatalyst to remove organic pollutants,dye-sensitized solar cells,self-cleaning,and sterilization.However,zinc oxide has a wide band gap and mainly absorbs ultraviolet light in sunlight?only 5%of sunlight?,so the utilization rate of sunlight is too low.In addition,porous zinc oxide facilitates the adsorption of pollutants and can adsorb more active sites.Therefore,adjusting the band gap and surface defects of porous zinc oxide to achieve effective absorption of visible light while improving the separation efficiency of photogenerated charges is still a challenging subject.In this paper,a porous black hexagonal zinc oxide photocatalytic material was first synthesized by a one-step hydrothermal and solid-state chemical reduction method.The crystal phase structure and surface defects are effectively controlled,which significantly improves the absorption of visible light and improves the separation efficiency of photogenerated electron-hole pairs.In order to improve the utilization of sunlight,metal doping is used to extend the light response range to the near-infrared region,and the introduction of precious metals to achieve the SPR effect can further improve the separation efficiency of photo-generated charges,thereby significantly improving the composite material.Solar photocatalytic performance.This article is divided into the following three sections:1.Zinc acetate is coated with ethylene glycol as a precursor,and block copolymer P123 is used as a surfactant.The black porous hexagonal ZnO is synthesized by hydrothermal combination with sodium borohydride high temperature hydrogenation reduction method.This black porous hexagonal shaped ZnO has the characteristics of being porous and large specific surface area.By calcining at 400 ? and sodium borohydride:ZnO=1:2,the photocatalytic material with the best defect concentration is obtained.The presence of surface defects reduces the band gap from 3.21 eV to 2.95 eV,and the specific surface area increases from 1.5 m² g^-1 to 26.7 m² g^-1?about 17 times?,the performance of black ZnO degrading tetracycline for 80 min is 3 times higher than that of the original ZnO.This is due to the formation of porous structures and oxygen vacancy defects.The reduced band gap widens the absorption range of sunlight.The appropriate amount of defects facilitates the separation of photogenerated charges.The porous structure provides a large number of surface active sites..2.Using zinc acetate and n-butyl aluminum oxide as precursors,a black porous hexagonal ZnO doped with Al was synthesized by solvothermal method.Al doping reduced the ZnO grain size from 54.69? to 48.11?,and the specific surface area increased from 36.7 m² g^-1 to 58.7 m²g^-1.By adjusting the doping amount of Al,the best degradation performance?3%-Al-OVZCHPs?was found.The degradation performance of 3%-Al-OVZCHPs for tetracycline in 80 min was double that of the previous black zinc oxide.Concentration defects,thereby adjusting the energy band structure of ZnO crystals,further reducing the band gap results,and Al doping increases the number of surface hydroxyl groups,promotes the formation of·OH and ·O^2-,and further improves the degradation performance.3.Using Al-doped ZnO as the host,the Ag/Al-ZnO composite material was prepared by photodeposition.This material will form a heterostructure at the interface between Ag and ZnO,and the loading of metallic Ag on the surface of zinc oxide realizes the surface plasmon resonance?SPR?effect,which is further promoted by the synergy between Al nanoparticles and Ag nanoparticles.The transmission and separation of photogenerated carriers are improved,and the separation efficiency of photogenerated electron-hole pairs is improved.The performance of Ag/Al-ZnO in degrading tetracycline at 80 min is about 1.8 times higher than that of Al/ZnO.This is due to the generation of the SPR effect.Photogenerated electrons can quickly migrate to precious metals,which can better promote the separation of photogenerated carriers,inhibit the recombination of electron holes,and thus improve the degradation performance.This new synthesis strategy provides new ideas for the development of plasma photocatalytic composite materials for solar energy conversion,and has potential application prospects in the field of clean energy.