有机燃料与氧化剂的化学计量比对La_(0.8)Sr_(0.2)CoO_3催化剂性能的影响  

Effect of Stoichiometric Ratio of Organic Fuel to Oxidizer on Performance of La_(0.8)Sr_(0.2)CoO_3 Catalysts in Methane Combustion

作　　者：刘伟[1] 罗来涛[1] 闵雯雯[1] 

机构地区：[1]南昌大学应用化学研究所,江西南昌330031

出　　处：《石油化工》2007年第11期1093-1098,共6页Petrochemical Technology

基　　金：高等学校博士学科点专项研究基金(20040403001);江西教育厅科研基金(2005035)

摘　　要：以D,L-丙氨酸为有机燃料,采用溶液燃烧法制备了钙钛矿型复合氧化物La0.8Sr0.2CoO3催化剂,研究了有机燃料与氧化剂的化学计量比(φ)对催化剂结构和性能的影响,考察了催化剂的甲烷燃烧活性,并对催化剂进行了表征。实验结果表明,La0.8Sr0.2CoO3催化剂具有钙钛矿型结构,催化剂的结构和性能随φ的不同而变化,当φ=1.52时所制备的催化剂活性最高,甲烷转化率达到50%和100%时的反应温度分别为460,540℃。该催化剂的平均晶粒度(12.32nm)较小,晶格畸变率(4.66×10-3)和比表面积(21.40m2/g)较大,表面和氧空穴处的化学吸附氧更容易移动,表观活化能(62.54kJ/mol)较低。Perovskite type of composite La0.8Sr0.2Co03 oxides were prepared by D, L - alanine solution combustion synthesis and used successfully in methane combustion as catalysts. The catalysts were characterized by means of XRD, FTIR, BET and H2 - TPR. Effect of stoichiometric ratio （φ） of organic fuel to oxidizer on structures and catalytic activities of the catalysts were studied. The results indicate that all composite La0.8Sr0.2Co03 oxides with different φ have perovskite structure. Their structures and catalytic activities vary along with the change of φ. Catalytic activity of La0.8Sr0.2Co03 catalyst with φ 1.52 is the best among all samples, whose T50 and T100 （ temperatures of methane conversions reaching 50% and 100% , respectively） correspond to 460 ℃ and 540℃. Activity of the catalyst can be explained in terms of small average crystal size（ 12.32 nm）, high specific surface area （21.40 m^2/g）, large extent of lattice distortion（4.66 × 10^-3 ）, low apparent activation energy（62.54 kJ/mol）, and more mobile chemical -adsorbed oxygen on catalyst surface and in oxygen vacancies.

关 键 词：有机燃料 氧化剂 化学计量比 溶液燃烧法 D L-丙氨酸 镧-锶-钴复合氧化物 钙钛矿型结构 甲烷催化燃烧 

分 类 号：TQ032[化学工程]