超临界流体干燥制备纳米Mn_xO_y

Preparation of Nanometer Mn_xO_y by SCFD Technique

以硝酸锰和氨水为主要原料,用"溶胶 凝胶"法结合"超临界流体干燥"技术制备纳米MnxOy气凝胶,在800℃下煅烧MnxOy气凝胶,用XRD和TEM进行表征,重点考察超临界干燥、煅烧工艺对MnxOy气凝胶晶态、形貌和尺寸的影响。结果表明,采用超临界干燥,可制得分散性好的疏松棕黑色Mn3O4球形颗粒,其粒径介于10～30nm之间;在800℃下热处理,Mn3O4球形颗粒进一步氧化转变为米粒状Mn2O3颗粒,粒径也相应增大。

Nanometer Mn_xO_y was prepared by sol-gel and superitical fluid drying(SCFD) methods from Mn(NO_3)_3 salts. The manganate aerogel was calcined at 800℃ in air after SCFD treatment.The samples were characterized by XRD and TEM techniques to find out how the preparation craft influnces mangnate aerogel crystal structure,features and dimensions.The result shows that:(1) The SCFD method can yield brown, well-dispersed nanometer Mn_(x)O_(y) powder composed of spherical particles,whose diameter is between 10～30nm; (2) At 800℃,by calcining Mn_(3)O_(4) aerogel, nanometer Mn_(2)O_(3) can be prepared,which is composed of rice form particles; (3) SCFD technique can solve the problem of 'reuniting' in the preparation of nanometer Mn_(x)O_(y).