Study On Preparation Of Catalyst By Cu-BTC As Precursorand And Its Catalytic Oxidation Of Toluene

Volatile organic compounds?VOCs?are one of the most important pollutants in the atmosphere.Catalytic combustion technology is an efficient and environmentally friendly treatment in the industry.The current research hotspot is to prepare simple,efficient and low-cost catalysts.In this study,Cu-BTC,a metal-organic framework material,was used as a template to respectively load Co or Mn elements with different contents,and finally calcined to form a composite metal catalyst for catalytic oxidation of toluene.The effects of metal element molar ratio,space velocity,water vapor and reaction time on the performance of the catalyst were investigated.Combined with SEM,XRD,BET,XPS,H₂-TPR,O₂-TPD,DRIFTS and other characterization methods,the kinetics and reaction mechanism of catalytic degradation of toluene were investigated.The conclusions are summarized as follows:?1?With the increase of the molar ratio of Co/Cu or Mn/Cu,the activity of the catalyst increases gradually.With the increase of the molar ratio of metal elements,it can be found from the SEM diagram that the particles supported on the catalyst surface gradually increase,and the content of Co and Mn is also gradually increased in the mapping.When Co/Cu and Mn/Cu mole ratio of 0.5:1,the catalyst CuCo_0.5O_x/C?T90=243??CuMn_0.5O_x/C?T90=233??of the active best.But the catalytic properties of two kinds of catalyst is decreased as the mole ratio further improve.?2?The effect of space velocity on toluene catalysis of CuCo and CuMn composite catalysts is affected.The lower the space velocity,the better the catalytic activity,especially at 20000 mL/?g h?space velocity.This is related to the residence time of toluene molecules on the surface of the catalyst.At low space velocity,toluene stays on the surface of the catalyst for a long time,which is conducive to the catalytic reaction.?3?Two cycles of reproducibility test of CuCo_0.5O_x/C and CuMn_0.5O_x/C,50 h stability test and water resistance tests of 10 vol.%and 20 vol.%of different water vapors were investigated.The conversion rate of the catalyst to toluene was less affected by water vapor,and the catalysts before and after the use of XRD showed that the crystal form did not change significantly,indicating that the stability of the catalyst was good.?4?Finally,the activation energy of catalytic reaction was analyzed from microcosmic point of view by reaction kinetics.As the molar ratio of Mn/Cu increases,the activation energy of composite metal oxide catalyst decreases gradually.CuMn_0.5O_x/C has the lowest activation energy of 75.8 kJ/mol,indicating that CuMn_0.5O_x/C has the best catalytic degradation performance for toluene.