不同晶型和形貌MnO2纳米材料的可控制备

以KMnO4为锰源, 采用水热技术在180 ℃条件下于不同种类酸溶液中可控制备了α-, β-, δ-MnO2, 系统研究了 K＋, H＋及阴离子对制备产物MnO2晶型和形貌的影响. 研究结果表明, K＋与H＋在反应体系中对于制备产物晶相的生成形成竞争性影响, 其量的大小对制备产物晶型具有控制作用, 高浓度K＋离子有助于生成α-MnO2, 而高浓度的H＋有利于生成β-MnO2; 阴离子的种类和浓度对制备产物MnO2的晶型和形貌无显著影响. 在对制备产物进行XRD, SEM和元素分析的基础上, 提出了不同晶型和形貌MnO2的可能形成机理.

Controlled Synthesis of Manganese Oxide Nanocomposites with Different Structures and Morphologies

Manganese oxides with α-,β- and δ-type structures were controllably synthesized by hydrother-mally treating KMnO_4 in different acid solutions at 180 ℃. The effects of metallic cations, H~+ and anions in the reaction system on the structures and morphologies of manganese oxide nanocomposites were investigated systematically. The experimental results indicated that cations played a major role in the formation of manganese oxide nanocomposites with different structures, and K~+ ions were in competition with H~+ ions in the solution for the formation of manganese oxide nanocomposites. Α-MnO_2 was formed when the amount of K~+ ions was higher than that of H~+ ions, while the higher amount of H~+ ions was favorable for the formation of β-MnO_2. On the other hand, both the type and the concentration of anions in the solution have no significant effect on the structure and morphology of manganese oxide nanocomposites. The possible formation mechanism was proposed on the basis of the characterization for the obtained manganese oxide nanocomposites by XRD, SEM and elemental analysis.