The Preparation Of Noble Metal-Supported Catalysts And Catalytic Performance For Volatile Organic Compounds

With the increasing air pollution, more people pay attention on the volatile organic compounds (VOCs) treatment, especially benzene, toluene and xylene (BTX). BTX are typical representatives of VOCs recognized as major contributor to air pollution. The pollution of BTX on environment is of concern due to its toxicity and carcinogenicity. Currently, catalytic oxidation is one of the most popular methods for BTX destruction. It is the key that catalyst choice and the structural properties of itself. Therefore, the paper are showed the catalysts by impregnation method and flame spray pyrolysis for catalytic performance of BTX to discuss their relationship.1. The catalyst1.0wt.%Pt-TiO2was prepared by liquid impregnation method, chloroplatinic acid and titanium dioxide (P90) as raw material. According to the H2-reduction and reducing agents, the catalysts were characterized by XRD, TEM, BET, and XPS for the interpretation of their catalytic performances. Nearly100%benzene conversion is achieved on Pt-TiO2-Na3Ct catalysts at approximate160℃. The catalysts reduced in the liquid phase have better catalytic activities than H2-reduced; the H2-reduced catalysts have better catalytic activities than unreduced ones. Metallic Pt nanoparticles and rich chemisorbed oxygen on the surface of metallic Pt nanoparticles are probably responsible for their high catalytic activities for benzene oxidation.2. The0.5wt.%Pd-SiO2nanocomposites particles were prepared in one step by flame spray pyrolysis. Precursor solutions were prepared by dissolving appropriate amounts of palladium acetylacetonate and hexamethyldisiloxane. The morphology of catalysts were changed by different temperature H2-reduction. The catalysts were characterized by XRD, TEM, BET, ICP and CO pulse chemisorption for the interpretation of their catalytic performances. Nearly100%toluene conversion is achieved on Pd-SiO2-800℃-H2catalysts at approximate165℃. Thermal treatment makes particle size and dispersion of Pd nanoparticles varied to the maximum turnover frequency (TOF) and best catalytic activity. It is concluded that Pd-SiO2catalysts with proper structural and morphological characteristics may be considered as promising candidates for the low-temperature reaction for catalytic oxidation of toluene. The Additionally, using part of catalysts showed the catalytic activities for BTX.