Co3O4纳米立方体的可控合成及其CO氧化反应性能

在乙醇和三乙胺的混合溶液中,采用溶剂热法制备了尺寸为10 nm的Co₃O₄立方体. 考察了钴盐前驱体和溶解氧对Co₃O₄纳米立方体结构的影响规律,通过对合成过程中不同阶段产物的结构分析和表征,提出了Co₃O₄纳米立方体的形成机制是溶解再结晶的过程. 将所制备的Co₃O₄纳米立方体在200 ℃焙烧处理后,尺寸和形貌均可保持稳定,但400 ℃焙烧后,变为球形纳米粒子. 这种主要暴露{100}晶面的Co₃O₄纳米立方体催化CO氧化反应的活性低于纳米粒子({111}晶面),验证了四氧化三钴纳米材料在CO氧化反应中的晶面效应.

Morphology-Controlled Synthesis of Co3O4 Nanocubes and Their Catalytic Performance in CO Oxidation

Co₃O₄ nanocubes that were exclusively terminated with {100} facets of edge size 10 nm were solvothermally fabricated in a mixed solution of ethanol and triethylamine. Analyses of the structural evolution of the intermediates at different intervals during the synthesis, together with an examination of the influences of the cobalt precursor and solvent on the product structure, showed that the formation of Co₃O₄ nanocubes followed a dissolution-recrystallization mechanism. After calcination at 200 ℃, the as-synthesized Co₃O₄ material retained a cubic morphology with the same edge size, but calcination at 400 ℃ resulted in the formation of spherical Co₃O₄ particles of diameter about 13 nm. The Co₃O₄ nanocubes exhibited inferior activity in room-temperature CO oxidation compared with Co₃O₄ nanoparticles ({111} facets), primarily as a result of the exposure of the less- reactive {100} facets, demonstrating the morphology effect of Co₃O₄ nanomaterials.