Preparation Of TiO₂/LDH/GO Composite Material And Its Photocatalytic Degradation Of Formaldehyde

Indoor formaldehyde mainly comes from daily necessities and interior decoration materials.Because of its wide source,the great harm to human body,and long duration,it has attracted widespread attention.Photocatalytic technology?POT?can completely oxidize organic pollution into clean substances such as carbon dioxide and water under the light.The photocatalyst conforms to the specific indoor environment due to its advantages such as non-toxic,harmless,high stability,no energy required for the reaction,and clean reaction products.Therefore,the photocatalytic technology is expected to become an effective means to control indoor air pollution.In this study,a new type of photocatalytic material Titanium Dioxide/Hydrotalcite/Graphene Oxide?TiO₂/LDH/GO?was prepared for indoor formaldehyde degradation.In this paper,modified Hummers were used to prepare Graphene Oxide?GO?.Coprecipitation method was used to prepare Hydrotalcite/Graphene Oxide?LDH/GO?.TiO₂ nanoparticles prepared by sol-gel method were prepared by hydrothermal method and loaded on the surface of LDH/GO.The characterization results show that the prepared TiO₂ is anatase crystal with good crystallinity and the particle diameter is about 3nm.LDH forms a groove on the surface of GO.The existence of LDH/GO solves the problem of agglomeration of TiO₂ nanoparticles,C-O-C bond and CO-Ti bond which is reflected by FT-IR and XPS confirmed the heterojunction structure generated by the interaction between GO,LDH,and TiO₂.The D,G,and 2D spectral absorption bands of GO observed by Raman prove that in the composite material GO still maintains a layered and ordered structure.Under the indoor environmental conditions,the photodegradation experiment of formaldehyde was carried out using a self-made photocatalytic reaction simulation box.The effect of TiO₂/LDH/GO on formaldehyde is 2.6 times that of pure TiO₂ particles.The degradation rate of formaldehyde in 3 hours reaches 77.8%,reducing formaldehyde gas with a concentration of 0.30mg/m³ to 0.068mg/m³,which is below national indoor air quality standards?0.08mg/m³?.By comparing the photocatalysis prepared by different calcination temperatures and LDH/GO ratio,the results show that the optimal ratio of LDH/GO loading is 5%?10%,and the optimal calcination temperature is 400??500?.After 5 repeated tests,the photocatalytic activity of TiO₂/LDH/GO did not decrease significantly,and the removal rate of formaldehyde could still reach 77.2%.The kinetic principle and photocatalytic mechanism of photocatalytic degradation of formaldehyde were studied and analyzed.The kinetic equations of photodegradation of formaldehyde at different catalyst dosages are completely combined with the L-H model?all R2 are greater than 0.98?.The photocatalytic mechanism elaborated on the adsorption process of TiO₂/LDH/GO,photoexcitation and electron transfer process,the process of oxidative elimination of formaldehyde,the adsorption performance of LDH,the transfer of LDH and GO to the photogenerated electron-hole pair of TiO₂,which is the main reason why TiO₂/LDH /GO has good catalytic performance.