摘要
利用有序介孔立方相(Ia3d)乙烯基三乙氧基硅烷(TEVS)为模板,通过纳米组装法在硅基硬模板的介孔中填入La-Fe-柠檬酸络合物,经焙烧和碱洗去除硅基模板,制备具有有序介孔结构且高比表面积的LaFeO_3钙钛矿(ABO_3),并与软模板法和自燃烧法制备的LaFeO_3钙钛矿催化剂作对比,运用XRD、TEM和BET对合成催化剂进行表征,以甲烷催化燃烧反应作为探针反应考察催化剂性能。广角XRD结果表明,3种方法均可制备主相结构为钙钛矿晶型的LaFeO_3,未检测到氧化镧或氧化铁的杂晶相。其中,采用硬模板组装法获得的介孔LaFeO_3钙钛矿的比表面积达59.33 m^2·g^(-1),其三维有序的介孔结构通过TEM以及小角XRD分析得以证明。在催化甲烷燃烧实验中,催化剂(硬模板组装法)呈现较传统方法(自燃烧法)制备LaFeO_3更高的活性,起始转化温度(T_(10))和半转化温度(T_(50))分别为402℃和479℃。
Mesoporous LaFeO3 perovskite （ AHO3 ） with high surface area was synthesized via nanocasting strategy by using highly ordered mesoporous cubic （Ia3d） vinyl triethoxy silane as the template and filling the mesopores in silica template with a La-Fe citrate complex precursor, followed by calcination and silica removal via washing with base solution, compared with LaFeO3 perovskite prepared by conventional autocombustion and microcrystal synthesis. The as-prepared samples were characterized by XRD, TEM, and nitrogen adsorption. Their catalytic performance were investigated using methane complete oxidation as the probe reaction. The results showed that the crystal phases of LaFeO3 perovskite were formed and no impurity phase of La-oxide/Fe-oxide was detected in the as-prepared samples ;The mesoporous LaFeO3 perovs- kite prepared by hard-template method had high specific surface area of 59.33 m2·g^-1 and three-dimensional ordered mesostructure,and exhibited higher activity for methane catalytic combustion than those prepared by conventional auto-combustion method. The light-off temperature （Tl0） and the half-conversion temperature （ T50 ） were 402 ℃ and 479 ℃ ,respectively.
出处
《工业催化》
CAS
2011年第9期19-24,共6页
Industrial Catalysis
基金
教育部高等学校博士点基金(20090010120003)
中央高校基本科研业务费(ZZ1003)
关键词
催化化学
介孔
LaFeO3钙钛矿
甲烷
催化燃烧
catalytic chemistry
mesoporous
LaFeO3 perovskite
methane
catalytic combustion
