低温燃烧合成法制备粒径相近的MnO、Mn3O4和Mn2O3纳米颗粒

通过控制硝酸盐(硝酸锰) 与有机燃料(尿素) 的摩尔比, 采用低温燃烧合成法制备了粒径相近、形貌不同的单相MnO、Mn₃O₄和Mn₂O₃纳米粒子。扫描电子显微形貌观察结果显示, 三种纳米粒子尺寸约为100 nm, 依据Mn离子价态的不同, 三种纳米粒子的形貌分别为链状、马铃薯状和球状; 热重-差热分析表明, 样品粒径大小主要取决于有机燃料的着火点; 磁性测量结果显示, 低温时MnO和Mn₂O₃粒子表现出弱铁磁性, 这主要归因于纳米颗粒表面存在未补偿的自旋。本文为制备不同价态高纯锰氧化物纳米颗粒提供了一种环境友好、工业稳定的途径。

Preparation of MnO,Mn3O4, and Mn2O3 nano-particles in similar sizes by low-temperature combustion synthesis method

The single-phase nano-particles of MnO, Mn₃O₄, and Mn₂O₃ in similar sizes and different morphologies were prepared by low-temperature combustion synthesis method through controlling the mole ratio of organic fuel (carbamide) and nitrate (manganese nitrate).Scanning electron microscopy shows that, the sizes of these three nanoparticles are about 100 nm in the morphologies as chain-like, potato-like, and ball-like, depending on the valence of Mn ions.The thermogravimetric–differential thermal analysis indicates that, the particle size is essentially determined by the ignition temperature of fuel.The magnetization measurements show that, the MnO and Mn₂O₃ nano-particles exhibit a weak ferromagnetic behavior at low temperature, which can be attributed to the presence of uncompensated spins on the surface of nanoparticles.This paper offers an environmental friendly and industrially steadily method to prepare the high-purity manganese oxide nano-particles in different Mn valence states.