N-doped graphene/CoFe(2)O(4) catalysts for the selective catalytic reduction of NO(x) by NH(3)

In this paper, CoFe(2)O(4)/graphene catalysts and N-doped graphene/CoFe(2)O(4) (CoFe(2)O(4)/graphene-(N)) catalysts were prepared using the hydrothermal crystallization method for the selective catalytic reduction of NO(x) by NH(3). The results of the test showed that CoFe(2)O(4)/graphene catalysts exhibited the best denitrification activity when the loading was at 4% and the conversion rate of NO(x) reached 99% at 250–300 °C. CoFe(2)O(4)/graphene-(N) catalysts presented a better denitrification activity at low temperature than CoFe(2)O(4)/graphene catalysts, and the conversion rate of NO(x) reached more than 95% at 200–300 °C. The intrinsic mechanism of CoFe(2)O(4)/graphene-(N) catalysts in promoting SCR activity was preliminarily explored. The physicochemical properties of the samples were characterized using XRD, TEM, N(2) adsorption, XPS, NH(3)-TPD, and H(2)-TPR. The results indicated that nitrogen doping can improve the dispersion of CoFe(2)O(4), and it also increased the acidic sites and the redox performance conducive to improving the denitrification activity of the catalysts. In addition, CoFe(2)O(4)/graphene-(N) catalysts demonstrated a better resistance to water and sulfur than CoFe(2)O(4)/graphene catalysts.