CAJ | 학술논문

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.
이초산시、초산란위전체,용안수공침정법제비료일계렬 Ce1-xLaxO2(x≤0.5)최화제,이용 XRD、N2흡부-탈부、SEM、Raman、H2-TPR 화 OSC 대최화제적물이화학성질진행료표정,병고찰기재갑완양록화반응중적최화성능.결과표명:Ce1-xLaxO2최화제적양화환원성질수착란함량적변화발생현저개변,병차저일성질적변화여반응적전화솔급산물분포구유교강적련계.Ce1-xLaxO2표면양물충적활발성대최화제활성영향현저,이체상양물충용역장생성적갑완록화물심도양화.재Ce1-xLaxO2(x<0.3)최화제상표면양물충기주도작용,록갑완위주요반응산물,Ce0.8La0.2O2최화제상록갑완선택성최고위52%.재체상양물충경활발적Ce0.7La0.3O2화Ce0.5La0.5O2상산물중CO적선택성현저상승,Ce0.5La0.5O2최화제상CO선택성고체48%.은정성측시표명Ce0.8La0.2O2최화제구유량호적은정성.
A series of Ce1-xLaxO2(x≤0.5) catalysts were prepared by ammoniaco-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(x<0.3) 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.