| With the development of urbanization and industrialization,the problem of air pollution is becoming more and more obvious.Volatile organic compounds（VOCs）are one of the important contributors of air pollutants.They are important precursors of ozone,photochemical smoke and aerosols,and are toxic to human skin or respiratory allergies,asthma,central nervous system and liver damage.Different VOCs removal techniques corresponding emerge in endlessly.With the country’s focus on environmental pollution and the introduction of stricter new regulations,the catalytic oxidation technology can completely under low temperature is converted into CO2 and H2O,which is considered to be one of the most promising technology due to high catalytic efficiency,low energy consumption,no secondary pollution,etc.The design and development of catalysts with high activity and stability is the key of this technology.At present,noble metal catalysts with superior activity are widely used in the catalytic degradation of VOCs.However,the application of noble metal catalysts in practical industry is limited by their high operating cost and high temperature sintering deactivation.Therefore,it is a key technical problem to develop and design highperformance catalysts with low cost,high activity and good thermal stability.At present,the monolithic catalyst has regular pore structure compared with the powder catalyst,which is conducive to the timely entry and discharge of reactants and products.The advantages of high utilization rate and good thermal stability are more and more widely used in the practical application process.Based on this,this paper takes the catalytic oxidation technology of toluene as the starting point of research,using cordierite honeycomb ceramics as the carrier,using template method and wet impregnation method combined technology to prepare the monolithic catalyst with low amount of noble metal Pt on cerium-zirconium oxide coating.The results showed that the CZO（Ce0.8Zr0.2O2）coating with three-dimensional ordered macroporous structure（3DOM）and the 0.5Pt/OM CZO catalyst with uniform particle size and suitable size Pt nanoparticles showed excellent catalytic activity for the catalytic oxidation of toluene to CO2 and H2O（T50=144℃,T90=186℃）.The main reason is that 0.5Pt/OM CZO has abundant oxygen adsorption species and good low temperature reduction performance.Furthermore,in situ DRIFTS showed that the catalytic oxidation of toluene was continuous oxidation process and the oxidation activity of adsorbed oxygen species compared to lattice oxygen was higher for toluene.In addition,the stability of 0.5Pt/OM CZO catalyst was studied by aging treatment under high temperature oxidation condition.The results showed that the catalyst has good thermal and hydrothermal stability,which is attributed to the stable anchorage of Pt on the surface of CZO by the Pt-O-Ce bond formed between Pt and the support.The 0.5Pt/OM CZO monolithic catalyst designed in this study has important reference significance for the development of high-performance catalysts. |
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