本文選題：介孔氧化硅 + 納米花��； 參考：《華南理工大學》2015年碩士論文

【摘要】：納米花狀的介孔氧化硅不僅具備介孔材料的一般特點,如比表面積高,結構規(guī)整有序,水熱穩(wěn)定性好和無毒、表面易于修飾等特點,而且其徑向開放的多級孔道結構極大的促進了底物分子的傳質和擴散,是制備催化劑的理想載體。本文采用溶劑熱法,以十六烷基溴化吡啶(CPB)為表面活性劑,在水、環(huán)己烷和戊醇組成的油水體系中合成了顆粒均勻,粒徑為200 nm,比表面積高達502 m2·g-1的多級孔道結構的介孔氧化硅納米花(mesoporous silica nanoflower,MSNF)。通過改變油水體積比、TEOS的濃度和水熱溫度,探究了反應條件對納米花形貌的影響。我們發(fā)現,環(huán)己烷對納米花形貌具有決定性的影響。此外,我們探究了加入第二模板劑對納米花形貌的影響并初步研究了采用硬模板法設計合成棉花球狀氧化硅。通過SEM、TEM、XRD、TG、FTIR、N2吸脫附等測試對合成的氧化硅材料的形貌和結構進行了表征,并對MSNF的形成過程進行了合理的推理和闡述。以MSNF為載體,采用浸漬-H2還原法制備了mono-Pd、mono-Au和Pd Au0.2催化劑樣品,并用于催化苯酚加氫的性能研究,研究了Au對Pd的添加效應。實驗表明,Pd Au0.2的催化活性是單金屬Pd和商業(yè)Pd/C的4倍和13倍。為了探究不同載體的雙金屬效應,我們選取了XC-72R、MCM-41、SBA-15、MCM-48為載體,制備一系列單金屬和Pd Au0.2雙金屬催化劑用于催化苯酚加氫反應。結果表明,以XC-72R為載體制備催化劑,Au的添加降低了Pd基催化劑的催化性能。與之相反,采用Si O2為載體制備的催化劑,Au的添加明顯提高了催化劑的催化性能。以下是不同介孔Si O2為載體制備的催化劑的催化性能排序:SBA-15MSNFMCM-48MCM-41。以MSNF為載體,采用浸漬-H2還原法制備了Pd Irn雙金屬催化劑并首次用于催化硝基苯加氫反應。探究了不同Pd/Ir摩爾比對催化劑性能的影響,篩選出Pd Ir比例最優(yōu)的催化劑樣品(nIr/nPd=0.4)。實驗結果表明,與mono-Pd和mono-Ir相比,在保持對苯胺的高選擇性(98%)的基礎上,Pd Ir0.4/MSNF在0.5h內對硝基苯的轉化率高達100%,分別是mono-Pd和mono-Ir的5倍和33倍。通過TEM、H2-TPR、XRD等測試,我們發(fā)現Ir的添加可以有效減小催化劑的粒徑,提高催化劑的抗團聚性能。
[Abstract]:Nano-flower-like mesoporous silica not only has the general characteristics of mesoporous materials, such as high specific surface area, orderly structure, good hydrothermal stability and non-toxic, surface easy to modify and so on. Moreover, its radial open multilevel pore structure greatly promotes the mass transfer and diffusion of substrate molecules, and is an ideal support for the preparation of catalysts. In this paper, a solvothermal method with cetylpyridine bromide (CPB) as surfactant was used to synthesize homogeneous particles in an oil-water system composed of water, cyclohexane and pentanol. The mesoporous silica nanorods with a diameter of 200nm and a specific surface area of 502m2 g ~ (-1) were obtained from the mesoporous silica nanorods (mesoporous silica nanoflower MSNF). By changing the concentration of TEOS and hydrothermal temperature, the effect of reaction conditions on the morphology of nano-flowers was investigated. We found that cyclohexane has a decisive effect on the morphology of nano-flowers. In addition, we investigated the effect of the addition of the second template on the morphology of the nano-flowers and studied the design and synthesis of cotton spherical silica by hard template method. The morphology and structure of the synthesized silicon oxide materials were characterized by the desorption and desorption tests, and the formation process of MSNF was reasoned and explained. Mono-Pdlmono-Au and PD Au0.2 catalysts were prepared by impregnation -H2 reduction method on MSNF-supported, and were used to study the catalytic properties of phenol hydrogenation. The effect of au on PD addition was studied. The results show that the catalytic activity of Pd Au0.2 is 4 and 13 times higher than that of single metal PD and commercial PD / C. In order to investigate the bimetallic effect of different supports, a series of monometallic and PD Au0.2 bimetallic catalysts were prepared on XC-72RNMCM-41 SBA-15MCM-48 to catalyze the hydrogenation of phenol. The results showed that the addition of au on XC-72R catalyst decreased the catalytic performance of PD based catalyst. On the contrary, the addition of au on Sio _ 2 supports can obviously improve the catalytic performance of the catalyst. The following is the order of catalytic performance of different mesoporous Sio _ 2 supported catalysts: 1 SBA-15 MSNFMCM-48MCM-41. PD Irn bimetallic catalyst was prepared by dipping H2 reduction method with MSNF as the carrier and was used for the hydrogenation of nitrobenzene for the first time. The influence of PD / ir molar ratio on catalyst performance was investigated. The best PD / ir ratio was obtained (nIrr / nPd0. 4). Compared with mono-Pd and mono-Ir, the conversion of PD Ir0.4 / MSNF to nitrobenzene in 0.5 h was 100 times higher than that of mono-Pd and mono-Ir, which was 5 and 33 times higher than that of mono-Pd and mono-Ir, respectively, on the basis of maintaining high selectivity for aniline (98%). By means of Tem H2-TPRO XRD, we found that the addition of ir can effectively reduce the particle size of the catalyst and improve the agglomeration resistance of the catalyst.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ127.2;O643.36

【參考文獻】

相關期刊論文 前1條

1 張嘉熙;黃高偉;張t$;何群華;黃超;楊旭;宋慧宇;梁振興;杜麗;廖世軍;;巰基功能化介孔材料高效錨定鈀負載型催化劑的制備及其苯酚加氫催化性能[J];催化學報;2013年08期

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本文編號：2116363