Study On The Catalytic Oxidation Of Formaldehyde Over Nano-gold Catalyst

Formaldehyde as a major indoor pollutant gas with the building materials, wall glue, plate and the use of a large number of furniture, as well as indoor smoking, has been a serious threat to human health. The catalytic oxidation method is considered to be the most ideal method in the removal of formaldehyde. This method has no secondary pollution, high efficiency and complete treatment, and the treatment of low-concentration formaldehyde is extremely effective. Therefore, a variety of Au catalysts were prepared by impregnation method with TiO₂, CeO2, FeOx as additives and Al₂O₃ as support in this thesis. The effect of the additives on the Au particle size and distribution, as well as catalytic oxidation of formaldehyde was studied. In addition, the effect of Co, Pt, Ag modification on catalytic activity of Au doped catalysts was investigated as well. XRD, BET, SEM techniques were used to characterize these catalysts. The main research results are as follows:1 Effect of TiO₂ additive on Au/TiO₂/Al₂O₃ composite catalyst catalytic oxidation of formaldehyde.The additive has a great impact on oxidation of formaldehyde over Au/Al₂O₃, and the effect of the reactivity is different with the different additives. The results show that the specific surface area of the catalyst decreased, and the ability of the catalytic oxidation of formaldehyde weaken gradually with the increase of TiO₂ loading. With the increasing dispersion of CeO2, the CeO2 grain size and the catalyst specific surface area decreased gradually, and the catalytic ability of the catalyst to enhance the oxidation of formaldehyde firstly increased and then decreased. Wherein Au/3%CeO2/Al₂O₃ catalyst shows the best catalytic oxidation at room temperature. The catalytic activity of gold catalyst was significantly improved by the doping of FeOx additive. The Au/1%FeOx/Al₂O₃ catalyst shows the best catalytic activity of formaldehyde oxidation, complete conversion rate can reach 83%. The catalytic activity order is Au/FeOx/Al₂O₃ > Au/CeO2/Al₂O₃ > Au/Al₂O₃ > Au/TiO₂/Al₂O₃.2 Effect of Au loading on the Au/FeOx/Al₂O₃ and Au/FeOx-CeO2/Al₂O₃ composite catalystThe catalytic activity of the two series catalysts gradually increases with the increasing of Au content. Based on the catalytic activity and economic aspects into account, 1%Au/1%FeOx-3%CeO2/Al₂O₃ catalyst is most ideal, the conversion rate of about 93%, and has good potential application prospects for indoor air purification.3 Effect of M?M=Co, Pt, Ag? doped for Au/FeOx-CeO2/Al₂O₃ composite catalyst complete oxidation of formaldehydeBased on both catalytic activity and economic considerations, 1%Au/1%FeOx-3%CeO2/Al₂O₃ catalyst for catalytic oxidation of formaldehyde is the most ideal. The purpose of this study is to observe the effect of Co, Pt and Ag doping on the ability of Au/FeOx-CeO2/Al₂O₃ catalyst for the catalytic oxidation of formaldehyde, and the catalysts were characterized by various technical means.