稻壳基活性炭催化剂的低温NH3-SCR抗硫性能

Sulfur resistance of rice husk based activated carbon catalyst for the low-temperature selective catalytic reduction of NO by NH3

以稻壳基活性炭(DAC)为载体,利用等体积浸渍法制备了DAC负载Mn、Ce氧化物的Mn-Ce/DAC脱硝催化剂,并用于氨法SCR反应.采用N2吸附、X射线衍射(XRD)、X射线光电子能谱(XPS)和程序升温吸附脱附(TPR/TPD)等手段对催化剂的物理化学性能进行了表征.结果发现与商业木屑基活性炭负载Mn、Ce氧化物催化剂(Mn-Ce/MAC)相比,Mn-Ce/DAC具有更高的Ce^3+/Ce^4+比率、表面化学吸附氧含量以及表面Brφnsted酸性位点,这与其优良的低温SCR活性及抗硫抗水性能直接相关.原位红外光谱结果显示在含硫气氛中Mn-Ce/DAC表面的硫酸盐含量明显低于Mn-Ce/MAC,表明前者具有优良抗硫性能.

A rice husk-derived activated carbon supported Mn-Ce catalyst(Mn-Ce/DAC)was prepared by an impregnation method and tested for the selective catalytic reduction of NOx with NH3.Such catalysts were characterized by N2 adsorption,X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and temperature programmed desorption(TPR/TPD).The characterization results indicated that Mn-Ce/DAC catalyst exhibited the higher Ce^3+/Ce^4+ratio,chemisorbed oxygen and Bronsted acid sites than commercial sawdust-derived activated carbon supported Mn-Ce catalyst(Mn-Ce/MAC).All of these factors played significant roles in the high SCR activity and SO2 resistance.In situ DRIFTS results demonstrated that sulfate formation was suppressed on the surface of the DAC support,which might be the most significant reason that Mn-Ce/DAC maintained a high SCR activity in the presence of SO2.