本文選題：氧化錳　切入點：特殊形貌　出處：《陜西師范大學(xué)》2015年碩士論文

【摘要】：氧化錳材料由于價格低廉、環(huán)境友好且資源豐富等優(yōu)點,已經(jīng)被廣泛應(yīng)用于催化、吸附、傳感、離子交換、鋰離子二次電池和超級電容器等領(lǐng)域。研究結(jié)果表明,材料的晶型、形貌、維數(shù)和尺寸等因素影響其光學(xué)、電學(xué)和磁學(xué)性能的發(fā)揮。控制制備具有特殊形貌氧化錳材料,進(jìn)而研究材料的形貌與性能之間的關(guān)系具有重要的理論和應(yīng)用價值。本論文以氧化錳材料為研究主體,通過水熱技術(shù)控制制備具有特殊形貌氧化錳材料,系統(tǒng)研究反應(yīng)條件對制備產(chǎn)物晶相和形貌的影響,探討了不同形貌氧化錳材料的生長過程及電化學(xué)性質(zhì)。全文包括緒論、實驗和總結(jié)三個部分。第1章緒論部分主要論述了特殊形貌過渡金屬氧化物的性質(zhì)、制備及應(yīng)用,氧化錳晶體的結(jié)構(gòu)、特殊形貌氧化錳材料的制備、應(yīng)用及形成機理；實驗部分第2章采用水熱技術(shù)制備了特殊形貌六角星形γ-MnOOH,提出了六角星形γ-MnOOH可能的形成過程；第3章以硫酸錳和過硫酸鉀為反應(yīng)體系,制備了四種不同形貌α-MnO2和特殊形貌(3-MnO2,在探討材料形成過程的基礎(chǔ)上,研究了不同形貌對材料電容性質(zhì)的影響；第4章為全文總結(jié)。在無模板劑或表面活性劑輔助下,以KMnO4為錳源,乙酸乙酯為還原劑和刻蝕劑,200℃水熱處理48 h,制備了新穎形貌六角星形γ-MnOOH。通過調(diào)節(jié)乙酸乙酯的用量、水熱反應(yīng)溫度和反應(yīng)時間等實驗參數(shù),得到了六角星形γ-MnOOH 最佳制備條件。應(yīng)用XRD、FE-SEM、TEM、HRTEM、SAED和原子吸收分析,對制備材料進(jìn)行了系統(tǒng)表征。在分析實驗結(jié)果的基礎(chǔ)上,提出了六角星形γ-MnOOH的形成過程。結(jié)果表明,乙酸乙酯對制備材料的形貌控制起到了非常重要的作用。隨著水熱時間的延長,乙酸乙酯緩慢分解產(chǎn)生乙酸,乙酸吸附在γ-MnOOH分支納米棒的側(cè)枝,發(fā)生溫和的酸刻蝕過程,納米棒逐漸變細(xì)變尖,最終得至γ-MnOOH六角星形形貌。將分支納米棒和六角星形γ-MnOOH進(jìn)行煅燒處理,六角星形γ-MnOOH經(jīng)過拓?fù)浠瘜W(xué)轉(zhuǎn)化,形成與前軀體形貌相同的α-MnO2。在無模板劑或表面活性劑輔助下,以硫酸錳和過硫酸鉀為研究體系,通過改變體系的溫度、濃度和酸度及向體系中添加不同金屬離子如鐵離子和銀離子,分別制備得到了微球狀、海膽狀、荔枝球狀和核-殼結(jié)構(gòu)四種不同形貌α-MnO2,系統(tǒng)研究了陽離子對制備產(chǎn)物晶相和形貌的影響。同時,通過改變反應(yīng)溫度,得到了特殊形貌谷粒狀β-MnO2。采用三電極體系,在1 mol L-1 Na2SO4電解液中對制備的四種不同形貌α-MnO2電極材料進(jìn)行電化學(xué)測試。結(jié)果表明,四種不同形貌α-MnO2材料中,核-殼結(jié)構(gòu)α-MnO2電極材料具有最好的電容性質(zhì),當(dāng)掃描速度為5mVs-1時,比電容為211 Fg-1。核-殼結(jié)構(gòu)α-MnO2電極材料具有的優(yōu)良電容性質(zhì)歸于材料特殊的核-殼結(jié)構(gòu),能夠縮短電解質(zhì)離子嵌入/脫出的路徑,提高材料的比電容。
[Abstract]:Manganese oxide has been widely used in the fields of catalysis, adsorption, sensing, ion exchange, lithium ion secondary battery and supercapacitor due to its advantages of low price, friendly environment and abundant resources.The results show that the crystal shape, morphology, dimension and size of the materials affect their optical, electrical and magnetic properties.It is of great theoretical and practical value to control the preparation of manganese oxide materials with special morphology, and to study the relationship between the morphology and properties of the materials.In this thesis, manganese oxide materials with special morphology were prepared by hydrothermal technology. The effects of reaction conditions on the crystal phase and morphology of the products were studied systematically.The growth process and electrochemical properties of manganese oxide materials with different morphologies were investigated.The thesis includes three parts: introduction, experiment and summary.Chapter 1 introduces the properties, preparation and application of transition metal oxides, the structure of manganese oxide crystal, the preparation, application and formation mechanism of manganese oxide materials with special morphology.In the second chapter of the experiment, the hexagonal star 緯 -MnOOH was prepared by hydrothermal technique, and the possible formation process of hexagonal star 緯 -MnOOH was proposed. Chapter 3 was composed of manganese sulfate and potassium persulfate.Four different morphologies of 偽 -MnO2 and special morphologies of 3-MnO _ 2 were prepared. Based on the study of the formation process of the materials, the effects of different morphologies on the capacitive properties of the materials were studied. Chapter 4 is a summary of the full text.A novel hexagonal star 緯 -MnOOH was prepared by hydrothermal treatment at 200 鈩，

本文編號：1693102