【摘要】 以La2O3和Co(NO3)2.6H2O为主要原料,用"超临界流体干燥"技术结合"溶胶-凝胶"法制备超细镧-钴混合氧化物。采用TG-DTA、XRD、FT-IR、TEM等手段进行表征;考察了超临界流体干燥技术对混合氧化物晶态和形貌的影响;并通过"2NO+2CO=N2+2CO2"的反应测试混合氧化物的催化活性。结果显示,260℃时,经超临界流体干燥得到的镧-钴混合氧化物为疏松、絮状且有较好分散性的棕色粉末,由大量直径小于10nm的球形小颗粒组成;850℃热处理后,镧-钴混合氧化物主要由晶态的LaCoO3、La2O3和非晶态的Co2O3组成;球形颗粒出现一定程度的团聚,粒径介于15～35nm;稀土镧影响了镧-钴混合氧化物中钴氧化物的晶化。更多还原

【Abstract】 Using La2O3 and Co(NO3)2·6H2O as raw material,lanthanum-cobalt mixed oxides were prepared by supercritical fluid drying technology and sol-gel method.The prepared materials were characterized by TG-DTA、XRD、FT-IR and TEM.The key aim was to examine the effect of supercritical fluid drying technology on the prepared materials’ crystalline and morphology.The catalytic property of mixed oxides were test by the reaction "2NO+2CO=N2+2CO2".The results showed: by supercritical fluid drying technology at 260℃,lanthanum-cobalt mixed oxides were brown-black,well-dispersed and flocculent powder which containing a large number of small spherical particles,whose diameters were less than 10 nm;After thermal treating at 850℃ for 2h under ambient atmosphere,the crystal components of the lanthanum-cobalt mixed oxides were LaCoO3 and La2O3,the amorphous form was Co2O3;There was a certain degree of agglomeration after thermal treating,the size of the particles was between 15~35nm;The presence of lanthanum affected cobalt oxide which existed in the lanthanum-cobalt mixed oxides crystallization.更多还原