發(fā)布時(shí)間：2018-06-25 09:19

  本文選題：發(fā)散狀孔道 + 200nm顆粒尺寸�。� 參考：《華東師范大學(xué)》2015年碩士論文

【摘要】：顆粒尺寸小于200 nm,特別是具有中心發(fā)散狀孔道結(jié)構(gòu)的樹枝狀介孔納米顆,因具有大的開放性孔道、高的可接觸內(nèi)表面積及小的顆粒尺寸,在細(xì)胞成像、疾病診斷、藥物/基因/蛋白質(zhì)儲(chǔ)存或傳遞、分離及多相催化方面有潛在應(yīng)用價(jià)值。很多科學(xué)家已經(jīng)成功制備具有發(fā)散狀孔道結(jié)構(gòu)的二氧化硅介孔納米顆粒,由于其表面豐富的羥基,可以通過硅烷化的方法在孔道內(nèi)引入多種有機(jī)功能基團(tuán),但是由于有機(jī)硅烷化試劑價(jià)格昂貴、重復(fù)使用率低以及非晶型硅基介孔材料水熱穩(wěn)定性差的缺點(diǎn),限制了它的應(yīng)用。碳材料不存在上述缺點(diǎn),并且具有良好的物理和化學(xué)穩(wěn)定性、特殊的電子性質(zhì)等優(yōu)點(diǎn),很多科學(xué)家已經(jīng)成功制備了不同形貌的碳材料。但是顆粒尺寸小于200 nm、具有發(fā)散狀孔道結(jié)構(gòu)的MCNs的制備仍存在挑戰(zhàn)。本文開展了三方面的研究工作,主要致力于通過調(diào)節(jié)體系pH影響正硅酸四乙酯的水解縮合速度以及酚醛樹脂的縮合速度來制備具有不同形貌和結(jié)構(gòu)的介孔碳硅復(fù)合納米材料MSCN,并通過處理后得到具有不同形貌和結(jié)構(gòu)特別是發(fā)散狀孔道的MCNs和MSNs。第一部分,利用具有發(fā)散狀孔道結(jié)構(gòu)的MSNs作為硬模板,分別選用蔗糖,間苯二酚、4-硝基酚作為碳源進(jìn)行澆筑,蔗糖與間苯二酚成功翻模MSNs的孔道結(jié)構(gòu),制備了具有發(fā)散狀孔道結(jié)構(gòu)、顆粒尺寸小于200 nm的MCNs,而4-硝基酚則不能,原因是4-硝基酚分子中只含有一個(gè)羥基,碳化過程中縮合程度不高導(dǎo)致；利用三聚氰胺和蔗糖作為共碳源成功制備保持球形結(jié)構(gòu)的N摻雜MCNs,但三聚氰胺量要控制在5%以下。第二部分,利用軟模板方法,通過調(diào)節(jié)體系pH控制TEOS的水解縮合速度以及酚醛樹脂的縮合速度,進(jìn)而影響酚醛樹脂與硅氧負(fù)離子與表面活性劑膠束的靜電作用,從而一步法得到具有不同形貌和結(jié)構(gòu)的MSCN;當(dāng)體系pH約為8時(shí),得到具有發(fā)散狀孔道結(jié)構(gòu)的MSCN,通過后期氮?dú)夥諊�下碳化、除硅或空氣氛圍下高溫焙燒分別得到具有發(fā)散狀孔道結(jié)構(gòu)的MCNs以及MSNs;在pH等于8的條件下,堿源種類不影響發(fā)散狀孔道的形成但是對(duì)于顆粒尺寸有影響,只有三乙醇胺作為堿源才能保持顆粒尺寸在200 nm以下,主要是三乙醇胺較強(qiáng)的氫鍵作用限制了顆粒的生長(zhǎng)。第三部分,對(duì)不同結(jié)構(gòu)的MCNs和MSNs進(jìn)行磺酸化處理,利用叔丁醇和.間甲酚作為探針反應(yīng)。具有發(fā)散狀孔道結(jié)構(gòu)的MCNs-B-1-S、MSNs-B-1-S催化該反應(yīng)的轉(zhuǎn)化率分別達(dá)到65%和58%,高于不同形貌的MCNs-S和MSNs-S以及其他體系催化劑,顯示了發(fā)散狀孔道結(jié)構(gòu)的優(yōu)勢(shì)。
[Abstract]:The particle size is less than 200 nm, especially the dendritic mesoporous nanoparticles with a central divergent pore structure, due to their large open channels, high contact internal surface area and small particle size, in cell imaging, disease diagnosis, Drug / gene / protein storage or transmission, separation and heterogeneous catalysis have potential applications. Many scientists have successfully prepared mesoporous silica nanoparticles with divergent pore structures. Because of their abundant hydroxyl groups on the surface, many organic functional groups can be introduced into the channels by silanization. However, its application is limited due to the high cost of organosilanization reagents, low reuse rate and poor hydrothermal stability of amorphous silicon-based mesoporous materials. Many scientists have successfully prepared carbon materials with different morphologies due to their good physical and chemical stability and special electronic properties. However, the preparation of MCNs with divergent pore structure and particle size less than 200 nm remains a challenge. In this paper, three aspects of research work have been carried out. The main purpose of this paper is to prepare mesoporous carbon silicon nanocomposite MSCN with different morphology and structure by adjusting the pH of the system to influence the hydrolysis rate of tetraethyl orthosilicate and the condensation rate of phenolic resin. MCNs and MSNs with different morphologies and structures, especially divergent pores. In the first part, MSNs with divergent pore structure were used as hard template, sucrose and resorcinol 4-nitrophenol were used as carbon source respectively. The pore structure of MSNs was successfully flipped between sucrose and resorcinol. MCNs with divergent pore structure and particle size less than 200 nm were prepared, but 4-nitrophenol was not. The reason was that there was only one hydroxyl group in 4-nitrophenol molecule and the condensation degree was not high during carbonization. Using melamine and sucrose as common carbon source, N-doped MCNs with spherical structure were successfully prepared, but the amount of melamine should be controlled below 5%. In the second part, by adjusting the pH of the system, the hydrolysis rate of TEOS and the condensation rate of phenolic resin are controlled by soft template method, and the electrostatic interaction between phenolic resin and silica anion and surfactant micelle is affected. MSCN with different morphology and structure was obtained by one-step method, and MSCN with divergent pore structure was obtained when pH was about 8, which was carbonized in the later nitrogen atmosphere. MCNs and MSNs with divergent pore structure were obtained by calcination at high temperature in the atmosphere of silicon removal or air respectively. When pH was equal to 8, the type of alkali source had no effect on the formation of divergent pore, but had an effect on particle size. Only triethanolamine as the base source can keep the particle size below 200 nm, mainly because of the strong hydrogen bond between triethanolamine and triethanolamine. In the third part, different structures of MCNs and MSNs were treated by sulfation, and tert-butanol and MSNs were used. M-cresol acts as a probe reaction. The conversion rate of MCNs-B-1-Sn MSNs-B-1-S with divergent pore structure reached 65% and 58% respectively, which was higher than that of MCNs-S and MSNs-S with different morphologies and other catalysts, showing the advantage of divergent pore structure.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：O643.36;TB332

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

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本文編號(hào)：2065433