中文摘要：

以硝酸铈、硝酸镧为前体,用氨水共沉淀法制备了一系列Ce1-xLaxO2（x≤0.5）催化剂,利用XRD、N2吸附-脱附、SEM、Raman、H2-TPR和OSC对催化剂的物理化学性质进行了表征,并考察其在甲烷氧氯化反应中的催化性能。结果表明：Ce1-xLaxO2催化剂的氧化还原性质随着镧含量的变化发生显著改变,并且这一性质的变化与反应的转化率及产物分布具有较强的联系。Ce1-xLaxO2表面氧物种的活泼性对催化剂活性影响显著,而体相氧物种容易将生成的甲烷氯化物深度氧化。在Ce1-xLaxO2（x〈0.3）催化剂上表面氧物种起主导作用,氯甲烷为主要反应产物,Ce0.8La0.2O2催化剂上氯甲烷选择性最高为52%。在体相氧物种更活泼的Ce0.7La0.3O2和Ce0.5La0.5O2上产物中CO的选择性显著上升,Ce0.5La0.5O2催化剂上CO选择性高达48%。稳定性测试表明Ce0.8La0.2O2催化剂具有良好的稳定性。

英文摘要：

A series of Ce1-xLaxO2（x≤0.5） catalysts were prepared by ammonia co-precipitation method and characterized by XRD,N2 adsorption-desorption,SEM,Raman,H2-TPR and OSC. Then their catalytic performances in CH4 oxy-chlorination to chloromethane were investigated. The results showed that the redox properties of Ce1-xLaxO2 changed significantly with the change of the lanthanum content,and there should be a strong link between this change and the conversion and product distribution. More specificly,the surface oxygen species had a remarkable influence on the activities of the catalysts,while advanced oxidation of the generated methane chloride was easily induced by bulk oxygen species. Chloromethane was the main product over Ce1-xLaxO2（x0.3） and the highest selectivity of chloromethane（52%） could be obtained over Ce0.8La0.2O2. A significant increase of CO selectivity was found over Ce0.7La0.3O2 and Ce0.5La0.5O2 as they had more active bulk oxygen species,and Ce0.5La0.5O2 showed the highest selectivity of CO（48%）. The long-term stability test showed thatCe0.8La0.2O2 catalyst had a good stability.