介孔Co3O4纳米片的结构和超级电容性能研究

摘要

Measurements of XRD (X-ray diffraction) ,TEM (transmission electron microscopy ) and N2 adsorption-desorption isotherms were combined to study the phase and microstructure of mesoporous Co3 O4 nanosheets synthesized at different temperatures . The mechanism of calcination temperature influencing the supercapacitive performance of the Co3 O4 nanosheets was also investigated .It is indicated from the XRD and TEM results that the as-prepared Co3 O4 nanosheets are in a pure spinel phase and in a mesoporous morphology, and the crystallinity increases with the calcination temperature. The N2 adsorption-desorption isotherms measurement shows a decrease of the specific surface area from 27.9 to 2.2mg as the calcination temperature increases from 300 to 500 ℃ . Electrochemical characterization reveals the best supercapacitor performance of the nanosheets obtained at 400 ℃ ,with a capacity of 151 F/g that is twice the values of the products calcined at 300 and 500 ℃ .Based on these results ,it was proposed that the synergistic effects of the crystallinity and the surface microstructure of the mesoporous microstructures are key factors for the supercapacitive performance of the Co3 O4 nanosheets .Compared with the nanosheets calcined at 300 ℃ ,the 400 ℃ sample possesses better crystallinity ,which is beneficial to the electron transfer during the redox reaction of the electrodes .In comparison with the nanosheets calcined at 500 ℃ ,the 400 ℃ calcined sheets have the proper BET specific surface area ,facilitating the participation of electrolyte in the electrode reaction .%利用X射线衍射（XRD ）、透射电子显微镜（T EM ）、恒温氮气吸附等技术，研究了不同焙烧温度下制备的介孔Co3 O4纳米片的物相和微结构特点，明确了焙烧温度影响介孔Co3 O4纳米片超级电容性能的微观机理．XRD和T EM 结果表明，不同焙烧温度下获得的产物均为尖晶石结构的介孔Co3 O4纳米片，且随着焙烧温度的升高，样品的结晶性增强．恒温氮气吸附结果表明，随着焙烧温度从300℃增加到500℃，介孔Co3 O4纳米片的BET 比表面积从27.9 m2/g降低到2.2 m2/g ．电化学测试结果表明，400℃焙烧产物具有最优的超级电容性能，其比电容值为151 F/g ，是300和500℃焙烧产物比电容值的2倍左右．基于上述表征结果，我们提出样品结晶性和表面微结构的协同作用是决定介孔Co3 O4纳米片超级电容性能的关键因素：与300℃焙烧样品相比，400℃焙烧产物具有更好的结晶性，利于电极氧化还原反应过程中电子的传输迁移；与500℃焙烧样品相比，400℃焙烧产物具有更为适中的B E T比表面积，利于电解液参与电极反应．