Preparation Of Nano-SiO₂ Material By Sol-gel Method And Its Application Research

Nano-SiO₂ has a broad application prospect because of its special structure.Therefore,the preparation and application of nano-SiO₂ is a very active field at home and abroad,and it is also the main object of this paper.In this paper,the sol-gel method was used to prepare SiO₂ sol,and the best preparation conditions were explored.The high-transmittance SiO₂ antireflection film is prepared by this method.Composite materials with higher photocatalytic activity.?1?Preparation of SiO₂ antireflection coatings using ethyl orthosilicate?TEOS?,absolute ethanol?Et OH?,deionized water?H₂O?as raw materials,and 28% ammonia water?NH3·H₂O?as a catalyst.The experimental results show that the optimal molar ratio of TEOS,Et OH,NH₃ · H₂O,H₂O is 1: 34: 0.056: 2,the best sol aging time is 15 d,At this time,the film has the best anti-reflection effect.It can reach about 98.5 %.The prepared SiO₂ sol is uniform and flat in size,loose in structure and high in film porosity.?2?Based on the preparation of SiO₂ antireflection film with ammonia water as a catalyst,a higher transmittance SiO₂ antireflection film was prepared by doping rare earth elements Er³⁺and Pr³⁺.Experiments show that the maximum transmittance of Er³⁺and Pr³⁺doped SiO₂ antireflection coatings can reach about 99.1 % and 99.4 %,respectively.Compared with98.5 % of SiO₂ antireflection coatings prepared by undoped alkali catalysis,the increase is about 0.6 % and 0.9 %.The doping of Pr³⁺and Er³⁺can increase the particle size of the SiO₂ sol,the nanoparticles are evenly and densely distributed,and the surface is flat.The prepared sol particles not only have high activity,but also have a large specific surface area,which is easy to agglomerate,and the resulting structure is more The loose secondary particles produce a film with higher transmittance and porosity.?3?Adopting sol-gel method,using ethyl orthosilicate and tetra-n-butyl titanate as precursors of composite sol,and using diethanolamine to control the polycondensation reaction of isopropyl titanate and ethyl orthosilicate,N-doped CNT/TiO₂/SiO₂ composites were prepared by in-situ growth method.soil region increased.The results show that the N-doped CNT/TiO₂/SiO₂ composite has better UV photocatalytic performance than the photocatalyst P25.In addition,the N element introduced is successfully doped into the TiO₂ lattice.Due to the hybridization of the 2p orbitals of N and O,the band gap width of the composite material is narrowed and the visible light activity is generated,thereby making N-doped CNT/TiO₂/SiO₂ composites have good visible light photocatalytic performance.