本文選題：錳氧化合物 + 納米材料��； 參考：《延邊大學》2015年碩士論文

【摘要】：錳氧化物作為一種重要的過渡金屬氧化物,由于其獨特的物理化學性質(zhì),在催化、電池、磁性和吸附等技術(shù)領(lǐng)域具有極其重要的研究意義和應(yīng)用價值.相比其體材料,錳氧化物納米材料顯現(xiàn)出更為優(yōu)異的性能,成為近年來材料研究領(lǐng)域的熱點.錳氧化物納米材料的性能與其形貌、尺寸和晶體結(jié)構(gòu)緊密相關(guān).因此,實現(xiàn)錳氧化物納米材料的可控制備,設(shè)計和制備出各種形貌、尺寸和結(jié)構(gòu)的錳氧化物納米材料成為合成領(lǐng)域的一個重要研究課題.以高錳酸鉀與乙二醇為原料,利用水熱法成功制備出γ-MnOOH納米棒,系統(tǒng)地研究了水熱反應(yīng)條件(反應(yīng)時間、反應(yīng)溫度)對最終產(chǎn)物形貌、尺寸及晶體結(jié)構(gòu)的影響,并對γ-MnOOH納米棒的形成機制進行了分析.研究發(fā)現(xiàn)在水熱體系中,γ-MnOOH納米棒的形成經(jīng)歷了片狀生長、自組裝與溶解再結(jié)晶三個階段,隨后在不同溫度與氣體氛圍中對γ-MnOOH納米棒煅燒獲得MnO2納米棒、Mn2O3納米棒和Mn3O4納米棒.研究結(jié)果表明γ-MnOOH是制備錳氧化物的理想前驅(qū)物.以KMnO4與NaHSO3為原料,利用水熱法實現(xiàn)了α-MnO2納米棒與γ-MnOOH納米棒的可控轉(zhuǎn)變.研究了水熱反應(yīng)條件(反應(yīng)物濃度比、反應(yīng)溫度)對最終產(chǎn)物形貌、尺寸及晶體結(jié)構(gòu)的影響.在反應(yīng)體系中,通過調(diào)節(jié)反應(yīng)物NaHSO3的濃度實現(xiàn)了α-MnO2納米棒與γ-MnOOH納米棒的水熱可控轉(zhuǎn)變.研究發(fā)現(xiàn)反應(yīng)溫度對α-MnO2納米棒的形貌有重要的影響,隨著反應(yīng)溫度的升高,產(chǎn)物的形貌經(jīng)歷顆粒狀—纖維狀—棒狀的變化.振動樣品磁強計(VSM)測量表明α-MnO2納米棒在室溫下表現(xiàn)順磁性.利用簡單、高產(chǎn)的低溫沉淀合成方法成功地制備出了各種晶體結(jié)構(gòu)與形貌的錳氧化物納米材料,系統(tǒng)地研究了反應(yīng)溫度、反應(yīng)時間、H2O2含量、反應(yīng)物濃度、堿的含量及不同堿源對錳氧化物納米材料形成的影響,研究發(fā)現(xiàn)通過調(diào)節(jié)H2O2含量或各種反應(yīng)物濃度比實現(xiàn)了γ-MnOOH納米棒、δ-MnO2納米片、α-Mn2O3納米立方塊和Mn3O4納米顆粒的可控制備.根據(jù)透射電子顯微鏡(TEM)的分析,我們提出了束狀γ-MnOOH納米棒的形成經(jīng)歷了片層生長、溶解再結(jié)晶和定向吸附三個階段.此外,在不同條件下對γ-MnOOH納米棒進行煅燒獲得了束狀MnO2,Mn2O3,和Mn3O4納米棒.
[Abstract]:Manganese oxide, as an important transition metal oxide, has great significance and application value in the fields of catalysis, battery, magnetism and adsorption due to its unique physical and chemical properties. Compared with the bulk materials, manganese oxide nanomaterials show more excellent properties and become a hot spot in the field of material research in recent years. The properties of manganese oxide nanomaterials are closely related to their morphology, size and crystal structure. Therefore, the controllable preparation of manganese oxide nanomaterials, the design and preparation of various morphologies, sizes and structures of manganese oxide nanomaterials have become an important research topic in the field of synthesis. 緯 -MnOOH nanorods were prepared by hydrothermal method using potassium permanganate and ethylene glycol as raw materials. The effects of hydrothermal reaction conditions (reaction time, reaction temperature) on the morphology, size and crystal structure of the final product were systematically studied. The formation mechanism of 緯-MnOOH nanorods was analyzed. It was found that the formation of 緯 -MnOOH nanorods in hydrothermal system underwent three stages: flake growth, self-assembly and dissolution and recrystallization, and then calcined 緯 -MnOOH nanorods at different temperatures and gas atmospheres to obtain MnO2 nanorods and Mn3O4 nanorods. The results show that 緯 -MnOOH is an ideal precursor for the preparation of manganese oxide. The controllable transition between 偽 -MnO2 nanorods and 緯 -MnOOH nanorods was realized by hydrothermal method using KMnO4 and NaHSO3 as raw materials. The effects of hydrothermal reaction conditions (reactant concentration ratio, reaction temperature) on the morphology, size and crystal structure of the final product were studied. In the reaction system, the hydrothermal transition between 偽 -MnO2 nanorods and 緯 -MnOOH nanorods was achieved by adjusting the concentration of the reactant NaHSO3. It was found that the reaction temperature had an important effect on the morphology of 偽 -MnO2 nanorods. With the increase of reaction temperature, the morphology of the products changed from granular to fibrous. Vibratory sample magnetometer (VSM) measurements show that 偽 -MnO2 nanorods exhibit paramagnetism at room temperature. Manganese oxide nanomaterials with various crystal structures and morphologies were successfully prepared by a simple and high-yielding low-temperature precipitation synthesis method. The reaction temperature, reaction time and concentration of H _ 2O _ 2 were systematically studied. The effects of alkali content and different alkali sources on the formation of manganese oxide nanomaterials were investigated. It was found that the controllable preparation of 緯 -MnOOH nanorods, 未 -MnO2 nanomaterials, 偽 -Mn2O3 cubic blocks and Mn3O4 nanoparticles could be achieved by adjusting the H2O2 content or the reactant concentration ratio. According to the analysis of TEM, we propose that the formation of bunchy 緯 -MnOOH nanorods goes through three stages: lamellar growth, dissolved recrystallization and directional adsorption. In addition, the 緯 -MnOOH nanorods were calcined under different conditions to obtain the bunched MNO _ 2o _ 2 mn _ 2O _ 3 and Mn3O4 nanorods.
【學位授予單位】：延邊大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O614.711

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相關(guān)期刊論文 前1條

1 袁中直;王輝;王莉;關(guān)菊英;肖信;;β-MnO_2納米帶的制備及其電催化氧還原活性[J];催化學報;2008年05期

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