CeO_2-La_2O_3/γ-Al_2O_3稀土氧化物混合物催化还原SO_2的实验研究

Experimental Study of Catalytic Reduction of SO_2 on CeO_2-La_2O_3/γ-Al_2O_3 Rare Earth Mixed Compounds

在La2 O3 中加入变价稀土氧化物CeO2 ,组成一种稀土氧化物的混合物 ,以这种混合物作为CO还原SO2 的催化剂 .采用连续流动固定床反应器 ,在反应气体SO2 和CO按SO2 ∶CO =1∶3,载流气体为N2 ,气体流量为 10 0 0mL/min的条件下 ,实验研究了该催化剂的活化过程以及温度和反应物浓度配比对活化反应的影响 ,用XRD和XPS对反应前后催化剂进行了表征 ,分析了相结构的变化 .结果表明 :CeO2 和La2 O3 2种稀土氧化物的混合物 ,在CO还原SO2 的催化反应中 ,活化温度比单个的CeO2 或La2 O3 氧化物下降了 5 0℃～ 10 0℃ ,而且具有更高的活性 .这可能是CeO2 和La2 O3 氧化物之间存在着某种协同作用所致 .

Addition of rare earth oxide CeO 2 with variable valences to La 2O 3 formed a mixture of rare earth oxides. This mixture can be used as the catalyst for the reduction of SO 2 by CO. In a fixed bed flow reactor, experimental were investigated for studing the activation process of this catalyst and effect factors such as temperature and concentration ratio of reactant on the activation reaction under the following conditions: composition of the gas mixture SO 2∶CO=1∶3, balancing with N 2 and feed flow rate 1000 mL/min. The phase structure changes of this catalyst were expressed with XRD and XPS. The results demonstrated that the activation temperature of CeO 2 La 2O 3/γ Al 2O 3 is 50～100℃ lower than that of a single component La 2O 3/γ Al 2O 3 or CeO 2/γ Al 2O 3, and the mixture of rare earth oxides has higher activity on catalytic reduction of SO 2 by CO. It's most likely that the result reveals on the synergism between CeO 2 and La 2O3.