The effect of oxides doping on the desulfurization performances of Fe2O3/AC catalyst

The oxidative modification of activated carbon was carried out using HNO₃, H₂O₂ and H₂SO₄, respectively. The supported Fe₂O₃/AC and Fe₂O₃-( CeO₂, La₂O₃, ZrO₂) /AC were prepared by impregnation precipitation method using urea as precipitant. The modified supports and catalysts were characterized by methods of Boehm titration, N₂ physical adsorption and X-ray diffraction. The reduction of SO₂ by CO was chosen to investigate the catalytic property and selectivity of the catalysts. The results indicated that the surface areas were increased after AC was modified with HNO₃ and H₂O₂, but that of AC modified with H₂SO₄ was reduced. The oxidative modification created more surface oxygen groups, and the highest catalytic activity for catalyst was obtained from the support modified with dilute nitric acid; the doping oxides could block the integrating of the Fe₂O₃ effectively, and then improve the dispersion of Fe₂O₃ on the catalyst support. The Fe₂O₃-ZrO₂/AC performed higher activity and selectivity in the reduction of SO₂ by CO.