Promotion Role Of K On The Performance Of Cu-K-O/AC Catalyst For The Reduction Of No By Activated Carbon

As one of the main pollutants in atmosphere, NOx can harm our health and the environment. Now, NH3-SCR of NOx is the most efficient and largely used method for the elimination of NOx, but it is difficult to store and transfer NH3, which produces easily the re-pollution of NH3 to the environment. In this thesis, activated carbon (AC) was used as both the reducing reagent and support of catalyst for the catalytic reduction of NO by AC, in which CuO was used as the catalyst and K2O was used as the promoter, and the effect of K on the performance of CuO catalyst was studied, in order to obtain a high activity and stability catalyst supported on activated carbon for the reduction of NO by carbon.Herein, the effects of the kind of AC, preparation condition, the content of K on the catalytic performance of CuO catalyst supported on AC were studied, and the physicochemical properties of catalyst were characterized by XRD, XPS, low-temperature N2 adsorption, TPD techniques and so on. The results show that, when the weight ratio of Cu and K is 2:1, the Cu-K-O/AC catalyst has higher activity and stability, for instance, over the 2Cu-K-O/AC catalyst, T100%(the temperature of complete reduction of NO) is～390℃. By means of the synergetic effect between CuO and K2O in the catalyst, its capacity for the NO adsorption can increase, which promotes the formation of the active sites of carbon and increase its catalytic activity. The presence of K can keep the stable surface concentrations of CuO and low valence Cu, resulting in an increase in the stability of catalyst. At 400℃, the conversion of NO can reach more than 95% over 2Cu-K-O/AC after used for 5 h.The HNO3, H2O2, H2SO4 and HC1 aqueous solutions and air were used as the oxidation reagent to pre-treat AC, and the results show that the oxidation treatment can obviously vary the physicochemical properties of AC. The number of the surface oxygen groups on AC is greatly increased after being oxidized by the HNO3 aqueous solution, which can improve the transfer and release the including-oxygen species produced in the reduction of NO and promote the dispersion of the copper active component on the surface of AC. Using 2Cu-K-O/AC-N catalyst, the temperature of complete reduction of NO is only at 310℃, and the excellent catalytic activity of 2Cu-K-O/AC-N can be kept after being used in the reaction of NO at 320℃for 5 h. For the 2Cu-K-O/AC-H catalyst pretreated by H2O2 aqueous solution, the presence of K can improve the stability of catalyst for the reduction of NO by AC.