本文選題：非水解溶膠-凝膠法 + 錫硅復(fù)合氧化物��； 參考：《山西大學(xué)》2015年碩士論文

【摘要】：氧化錫的用途非常廣泛,常用于電極材料和還原性氣體傳感器的制作,也充當(dāng)固體酸催化劑和有機物氧化催化劑等。氧化錫作為活性組分,在催化應(yīng)用中常與載體材料氧化硅、氧化鋁復(fù)合后使用,復(fù)合后的結(jié)構(gòu)、織構(gòu)、形貌等特征是影響催化性能的主要因素。這些結(jié)構(gòu)參數(shù)需在制備過程中進行調(diào)整和控制。制備復(fù)合氧化物的常見的化學(xué)方法有：共沉淀法、浸漬法、水熱法(包括溶劑熱法)和溶膠-凝膠法等。在過去的10到20年間,非水溶膠-凝膠方法逐步發(fā)展起來,成為制備金屬氧化物材料強有力的工具,特別是在制備金屬復(fù)合氧化物材料和有機-無機雜化材料方面,在金屬氧化物納米顆粒尺寸、形貌和晶體結(jié)構(gòu)控制方面體現(xiàn)出優(yōu)勢。非水解過程的特點是聚合度高于水解過程,非水過程中有機成分的變化對其過程有重要的影響,在合成納米氧化物顆粒的同時,形成的有機衍生物具有配位能力,這些衍生物對納米顆粒的大小、形狀、晶體結(jié)構(gòu)及納米顆粒的聚集形態(tài)等都具有重要的影響。非水過程制備復(fù)合氧化物的優(yōu)勢是簡便,可以經(jīng)一步反應(yīng)就制備多組分的可控組成和織構(gòu)的氧化物材料,不用使用昂貴的前驅(qū)物、反應(yīng)修飾物、多步的制備程序、模板劑、超臨界干燥等；可在沒有表面活性劑的條件下,制備出結(jié)晶良好的金屬氧化物納米顆粒。非水過程的主要缺點是需要在無水條件進行反應(yīng),一般需要加熱才能發(fā)生聚合。本研究研究內(nèi)容分為兩部分：(1)在課題組前期工作的基礎(chǔ)上,改進制備錫硅復(fù)合氧化物的非水溶膠-凝膠方法。一是改變制備工藝,將水熱工藝改為回流工藝,以期提高復(fù)合氧化物的產(chǎn)率；二是加入三氯化鐵催化劑,提高非水反應(yīng)過程速度和聚合度。研究這些工藝條件改變對材料結(jié)構(gòu)、織構(gòu)、形貌等特征的影響。(2)制備錫鋁復(fù)合氧化物,考察不同種類的氧供體：Pri2O、Et2O、MeOH、EtOH對材料的結(jié)構(gòu)、織構(gòu)、形貌等特征的影響。獲得的主要結(jié)果有：(1)在引入催化劑FeCl3條件下回流工藝制備的錫硅復(fù)合材料,比表面積和孔容明顯增加,比表面積從22.58 m2/g增加到305.7m2/g,孔容從0.047 cm3/g增到0.14cm3/g,同時平均孔徑明顯減小,復(fù)合氧化物產(chǎn)率從31%提高到60%左右。催化劑FeCl3的引入促進了非水解反應(yīng)過程中Sn-O-Si鍵的形成,有利于Sn-O-Si的過飽和析出,四方金紅石結(jié)構(gòu)的Sn02分散在無定形態(tài)的Si02中。(2)以乙醚和甲醇為氧供體制備的錫鋁復(fù)合氧化物材料,具有較高的分子水平混合度,700℃高溫焙燒條件下沒有出現(xiàn)完整的晶體；異丙醚和乙醇為氧供體獲得的復(fù)合氧化物,在600℃以上高溫焙燒后出現(xiàn)了Sn02結(jié)晶衍射峰；其復(fù)合組分的穩(wěn)定性遠(yuǎn)超其他方法獲得的材料。這充分說明,非水路線能夠更好地防止納米顆粒的聚集,獲得納米尺度的氧化物和復(fù)合均勻的氧化物,這可能是由于有機副產(chǎn)物吸附在顆粒表面,使其在焙燒過程中不易聚集成較大的顆粒。
[Abstract]:Tin oxide is widely used in the manufacture of electrode materials and reductive gas sensors, as well as solid acid catalyst and organic oxidation catalyst. As an active component, the structure, texture and morphology of tin oxide are the main factors affecting the catalytic performance. These structural parameters need to be adjusted and controlled during preparation. The common chemical methods for the preparation of composite oxides include coprecipitation, impregnation, hydrothermal (including solvothermal) and sol-gel methods. Over the past 10 to 20 years, the non-hydrosol gel method has evolved into a powerful tool for the preparation of metal oxide materials, especially in the preparation of metal composite oxide materials and organic-inorganic hybrid materials. It has advantages in controlling the size, morphology and crystal structure of metal oxide nanoparticles. The characteristics of the non-hydrolysis process are that the degree of polymerization is higher than that of the hydrolysis process, and the changes of organic components in the non-aqueous process have an important influence on the process. These derivatives have an important influence on the size, shape, crystal structure and aggregation morphology of nanoparticles. The advantage of preparing composite oxides in non-aqueous processes is that they can be prepared by one step reaction to prepare multicomponent controllable composition and texture oxide materials without the use of expensive precursors, reaction modifiers, multistep preparation procedures, templates, etc. Metal oxide nanoparticles with good crystallization can be prepared by supercritical drying without surfactant. The main drawback of non-aqueous processes is that they need to react in anhydrous conditions. This study is divided into two parts: 1) on the basis of the previous work of the research group, the non-hydrosol gel method for the preparation of tin / silicon composite oxides has been improved. One is to change the preparation process from hydrothermal process to reflux process in order to improve the yield of complex oxides and the other is to increase the rate of non-aqueous reaction and the degree of polymerization by adding ferric chloride catalyst. The effects of these technological conditions on the structure, texture and morphology of the materials were investigated. (2) the effects of different oxygen donors, such as oxygen donor: Pri2OEt2O-MeOH2O-EtOH, on the structure, texture and morphology of the materials were investigated. The main results obtained are as follows: (1) the specific surface area and pore volume of the Sn-Si composites prepared by reflux process under the condition of introducing catalyst FeCl3 increased obviously, the specific surface area increased from 22.58 m2 / g to 305.7 m2 / g, the pore volume increased from 0.047 cm3/g to 0.14 cm 3 / g, and the average pore size decreased significantly. The yield of compound oxide increased from 31% to 60%. The introduction of catalyst FeCl3 promoted the formation of Sn-O-Si bond in the process of unhydrolytic reaction, which was beneficial to the supersaturated precipitation of Sn-O-Si. Tetragonal rutile Sn02 was dispersed in amorphous Si02. The composite oxides obtained from isopropyl ether and ethanol were calcined at high temperature above 600 鈩，

本文編號：1882667