水热-固相热解法制备不同形貌的四氧化三钴纳米微粉

以氨水和氢氧化钾水溶液为沉淀剂,利用沉淀-固相热解法和中压水热-固相热解法,制备了不同形貌的Co₃O₄纳米微粉.在水热条件下,得到了立方和六角片状的Co₃O₄微粉,采用XRD和TEM等手段跟踪反应过程并表征产物,在此水热反应体系中影响产物Co₃O₄形貌的主要因素是pH值和NO₃^-.

Synthesis of Co3O4 Nanopowder with Different Morphologies by Hydrothermal Treatment Followed by Decomposition

The powder of Co₃O₄with a cubic structure and well-developed hexagonal platelets were synthesized hydrothermally, followed by decomposition of the precursors in the Co(NO₃)₂-NH₃or KOH system. The results of XRD and TEM which were used to monitor the processes of hydrothermal treatment and calcination showed that NO₃^-played a key role in the formation of Co₃O₄with different morphologies. Co₃O₄with a cubic structure could be directly prepared hydrothermally from the system with NO₃^-. After the NO₃^-was rinsed from the system, a topotactic phenomena was observed. Well-developed hexagonal platelets of β-Co(OH)₂were obtained from the hydrothermal system, and then, being baked at 300 ℃ in air, β-Co(OH)₂was transformed into Co₃O₄with the same morphology as the precursor.