以介孔氧化硅材料MCM-41为模板,硝酸锰为锰源,通过浸渍、450℃焙烧4 h得到Mn-MCM-41,用NaOH溶液溶解除去氧化硅模板得到锰氧化物,采用XRD,HRTEM和N2吸附-脱附等测试技术对产物进行了表征.结果表明,所得产物是纯相的β-MnO2纳米纤维,直径小于3 nm.纳米纤维之间有序排列组成类似MCM-41模板的介孔结构,其比表面积达到136.5 m2/g.将所制备的β-MnO2纳米纤维用于催化过氧化氢氧化分解质量浓度为60 mg/L的亚甲基蓝(MB)模拟染料废水,经100 min反应后,亚甲基蓝水溶液脱色率达到97.59%.所制备的催化剂对降解处理高浓度亚甲基蓝溶液,具有降解脱色率高和反应速度快等优点.
β-MnO2 nanofibers were successfully prepared based on MCM-41 mesoporous template.Firstly,Mn-MCM-41 was synthesized by impregnating mesoporous MCM-41 template with an aqueous ethanol solution of Mn(NO3)2 and heating at 450 ℃ for 4 h under air,and then the manganese oxide was obtained through dissolving the MCM-41 template with NaOH solution.Through X-ray diffraction,high resolution transmission electron microscopy and N2 adsorption and desorption isotherm characterizations,the as-prepared manganese oxide was shown to be the pure phase of β-MnO2 nanofibers with diameters less than 3 nm.These ordered β-MnO2 nanofibers formed a mesoporous structure similar to the MCM-41 template,with a high surface area of 136.5 m2/g.We demonstrated the high catalytic efficiency of β-MnO2 nanofibers as catalyst in the oxidation of methylene blue(MB) dye with H2O2.The decoloration rate of 60 mg/L MB solution reached 97.59% within 100 min,indicating that the catalyst can degrade high concentration of MB solution efficiently.