【作者】 张安峰；

【导师】 郭新闻； 张永春；

【作者基本信息】 大连理工大学 ， 工业催化， 2010， 博士

【摘要】 自1992年Mobil公司发现M41s以来,有序介孔材料因在吸附、分离、催化等领域具有重要的应用价值而成为研究者关注的焦点之一；而介孔材料的形貌、尺寸、孔径、介孔孔道方向等功能化控制又对其应用有着重要影响。本论文通过在油-液界面与固-液界面上合成具有特定形貌的介孔二氧化硅,对介孔孔道方向的控制进行了较为深入的研究,主要内容如下：以正硅酸乙酯为硅源、P123为介孔模板剂、苯的微乳滴为空心球球核模板,通过溶胶-凝胶法,在苯-水的油-液界面上,水热合成了介孔孔道沿径向垂直穿透球壳的二氧化硅空心球。研究发现,苯对P123胶束的初始定向作用是介孔孔道沿径向分布的原因；球壳上的介孔孔道是互相连通的；以介孔硅空心球为硬模板,糠醇为碳的前驱体,草酸为糠醇聚合催化剂,通过纳米浇铸法,合成了介孔碳空心球。通过分步向阳极氧化铝膜(AAO)的孔道内加入正硅酸乙酯与P123酸溶液,使正硅酸乙酯与P123酸溶液在AAO孔道内壁上分层分布,并水解、聚合、自组装,在AAO孔道与反应物的固-液界面上合成了介孔孔道垂直穿透管壁的硅纳米管；其形貌取决于AAO的孔道结构,管壁上的介孔孔径约为10 nm,呈平面六方排列。研究发现,吸附在AAO孔道内壁上的正硅酸乙酯与P123酸溶液水解形成的溶胶的量,是决定硅纳米管管壁上介孔孔道方向的原因：当溶胶生成的硅纳米管壁厚小于2个介孔孔道重复周期时,介孔孔道垂直穿透硅纳米管管壁,管壁厚度约为15 nm ;当壁厚大于2个介孔孔道重复周期时,介孔孔道环绕管轴或者平行管轴,管壁厚度约为40-60 nm。在合成介孔孔道垂直穿透管壁的硅纳米管过程中,在硅源中加入助剂苯,可以扩大管壁上的介孔孔径至15nm左右,此时介孔的有序度下降。研究发现,改变正硅酸乙酯与P123酸溶液向AAO孔道中添加的顺序,通过抽滤AAO膜,调节孔道中反应物的摩尔比,同样可以合成具有不同介孔孔道方向的硅纳米管,但是介孔的有序度下降。以正硅酸乙酯在P123酸溶液中预水解形成的SBA-15前驱体在AAO孔道内反应,可以合成介孔孔道方向垂直膜片的致密SiO2-AAO复合膜；盐酸溶解AAO膜,得到介孔孔道平行长轴的SBA-15纳米线。在聚碳酸酯膜孔道的内壁上同样可以合成介孔孔道垂直穿透管壁的硅纳米管。通过调变聚碳酸酯膜孔道的直径可以合成具有不同管径的硅纳米管,分别为200、100和50nm。由于聚碳酸酯膜孔道曲率的影响,硅纳米管管壁上介孔有序度随着管径的减小而降低,逐渐从平面六方排列趋向不规则。更多还原

【Abstract】 Ordered mesoporous materials have been studied extensively in the fields of adsorption, separation, catalysis and so on, since the discovery of M41s by Mobil in 1992. Methods to tune the morphology, pore and particle size of the mesoporous materials, as well as control the direction of the nanochannels of mesopores have become a hot issue for the purpose of practical applications. Current work mainly focused on the synthesis of mesoporous materials with particular morphology at the interface of oil-liquid and solid-liquid, especially on the direction control of the nanochannels of mesopores. The details are as follows:Hollow silica spheres with a mesoporous shell perforated by hexagonally-arrayed cylindrical nanochannels have been synthesized by sol-gel method with TEOS as silica source, P123 as template agent, and benzene microemulsion droplets as a core template for hollow sphere. The initial orientation of P123 micelles determined by the role of benzene decides the direction of the nanochannels of mesopores which perforate the shell along radial direction. The nanochannels are inter-connected. Hollow carbon spheres with a mesoporous shell are synthesized via nano-casting method using mesoporous hollow silica spheres as hard templates, furfuryl alcohol as carbon precursor, and oxalic acid as polymerization catalyst.Silica nanotubes with a mesoporous wall are synthesized in the channel of Anodic alumina oxide membrane (AAO) by sol-gel method using TEOS as silica source and P123 solution as template agent which are added to the channels one after another. The morphology of the silica nanotube depends on the pore structure of AAO. The thickness of the gel formed via the hydolysis of TEOS and acid solution of P123 on the channel surface of AAO determines the direction of the nanochannels of mesopores in the silica nonotube wall. When the thickness of the gel is less than two repeat distances of mesopores, the nanochannels of the mesopores perforate the silica nanotube wall vertically; when the thickness of the gel is thicker than two repeat distances of mesopores, the nanochannels of the mesopores surround the nanotube axis or parallel to the axis. And the thickness of the nanotube wall is about 15 and 40-60 nm respectively. The size of the hexagonally-arrayed mesopores in the silica nanotube wall is about 10 nm. Adding benzene to TEOS can expand the diameter of mesopores to 15 nm, and the arrangement of the mesopores is less ordered. SiO2-AAO composite membrane with perpendicular nanochannels of mesopores can be synthesized with precursor solution of SBA-15 formed via pre-hydrolysis of TEOS in the acid solution of P1 23. After the dissolution of Anodic alumina oxide membrane by hydrochloric acid, silica nanorods with nanochannels of mesopores parallel to the long axis are obtained.Silica nanotubes with mesopores perforating the wall vertically are also synthesized on the channel surface of polycarbonate membranes. The diameter of the silica nanotube is determined by the diameter of the pores of polycarbonate membranes, which is about 200, 100,50 nm respectively. Due to the curvature impact of the silica nanotube, the order degree of the mesopores in the wall reduces with the decreasing of the nanotube diameter, namely, hexagonally-arrayed mesopores trend to arrange irregularly.更多还原