NO Catalytic Oxidation Behaviors And Modification Of CoOx/TiO₂ Catalysts

NO catalytic oxidation is the key technology for commercial process to control NOx from stationary sources, due to its significant role in SCR technique and wet denitration processing. Increasing the oxidation degree of NOx(NO2/NOx) can effectively improve the reaction efficiency and the rate of the low-temperature SCR technology and wet deNOx processing.However, for the present research focused on NO catalytic oxidation, the high price of noble metals, the low activity of catalysts in low-temperature range, and the bad dispersion of active component were the main obstacles.These disadvantages limit the industrial application of NO catalytic oxidation.In order to solve these problems, the NO catalytic oxidation process was investigated by using titanium based metal oxides catalysts prepared by sol-gel method.In this paper, the catalysts loaded different metal oxides were prepared and the oxidation efficiencies of the catalysts were investaged.The results showed that CoOx had a good catalytic efficiency of NO oxidation. Furthermore the influence of the catalyst preparation conditions (metal loading, calcinations temperature) on the catalytic oxidation of NO was also investigated. With the characterization of the catalysts by BET, XRD,XPS and TEM, it was found that the main active phase in CoOx/TiO2 catalyst prepared by sol-gel method was Co3O4, and CoOx was well dispersed on the catalyst surface.The improvement catalytic oxidation efficiency of 9%CoOx/TiO2(450) was associated with well dispersed CoOx, the improvement of the surface area,the chemisorbed oxygen and the redox properties.Furthermore, the operating parameters of NO catalytic oxidation process including reaction temperature, GHSV, O2 concentration and NO concentration were investigated for the future application of this technology.To retard the sintering of the active component, other metal oxides were added into the CoOx/TiO2 catalysts. From the characterization of the catalysts by BET, XRD,XPS and TEM, it was found that the Oxygen storage capacity and the function of CoOx and CeOx between TiO2 were improved aftering the doping of CeOx, and the NO catalytic oxidation efficiency was improved. The good catalytic oxidation efficiency of 9%CoOx-5%CeOx/TiO2 was associated with the increasing chemical adsorptive oxygen and Ce oxidation valence.