Abstract:
An activated carbon (AC) was oxidized with air at 300℃ for 4 h or with 30 wt% HNO
3 at 60℃ for 4 h under reflux before it was loaded with CeO
2 by an impregnation method to prepare CeO
2/AC catalysts for the selective catalytic reduction of NO
x in flue gas with NH
3. The influence of the oxidation method on the performance of the catalysts was investigated. Both catalysts were characterized by FTIR, N
2 adsorption, XRD, temperature-programmed desorption of NH
3 and temperature-programmed reduction with H
2. Results showed that the HNO
3 oxidation increased both the number of oxygen functional groups and the surface acidity of the AC and the redox activity of the CeO
2/AC-HNO
3, which favored the adsorption and activation of NH
3 with the CeO
2/AC-HNO
3 and hence its catalytic performance. The onset and full conversion temperatures of NO
x over the CeO
2/AC-HNO
3 catalyst were 75 and 190℃, respectively, which were significantly lower than those over the CeO
2/AC-air catalyst. However, the activity of the CeO
2/AC-HNO
3 catalyst was easily inhibited by H
2O.