Nanoporous Oxides and Organic-Inorganic Hybrid Materials for Catalysis and Biomedical Applications

孔径在1-100 nm范围内的纳米材料，即纳米孔，由于在工业催化、环境修复以及作为药物/基因传递的生物相容载体方面的应用前景而引起人们的极大兴趣。特别是，介孔材料被定义为含有周期性排列的大通道或笼子的无机骨架(例如，二氧化硅、金属氧化物、碳)，通常为2至15 nm。这种孔径范围提供了高比表面积和高孔容，使这些材料成为多功能催化剂或催化剂载体，以及生物活性物质的潜在宿主/转运体。 这项研究计划的主要目标是：1)开发新的高活性和低成本的非贵金属催化剂家族，用于可持续的化学生产和与能源相关的应用(例如制氢、电催化)；以及2)设计生物兼容的纳米多孔杂化材料，包含理想的官能团并具有足够的结构和颗粒尺寸用于生物医学应用(例如药物输送)。除了合成和功能化外，重点将放在评估催化剂和生物材料的性能以及调整结构-性能关系上。介孔二氧化硅材料，如MCM-48、SBA-15，可以通过结构导向胶束聚集体和无机溶胶-凝胶法相结合的模板方法轻松地制备，从而形成尺寸和形状确定的特定纳米孔。这些(纳米)结构是设计催化剂和药物输送系统的良好起点。模板化介孔二氧化硅被认为是无毒的，在化学和热稳定性方面。它们的表面硅醇基允许固定许多不同的官能团。此外，为了优化吸附和扩散参数，可以对孔结构(大小、形状)进行调整。此外，可以控制材料颗粒的形态和尺寸以形成胶体(纳米)球或薄膜。根据目标应用的不同，介孔二氧化硅将采用不同的功能化方法(例如，通过浸渍或包裹插入金属阳离子和氧化物纳米颗粒；有机硅烷的空间选择性接枝；与功能(生物)聚合物的偶联)。无硅高比表面积混合金属氧化物组合物(例如，铜、镍、锰、锌等)还将使用纳米铸造法生产，这种方法是将金属盐浸渍到二氧化硅的孔中，作为硬模板(随后去除二氧化硅)，或使用纳米结构层状氢氧化物前体。除了二氧化硅和氧化物外，介孔碳载体还将通过二氧化硅纳米浇铸和表面活性剂辅助合成两种方法合成，然后进行修饰以引入金属阳离子/氧化物中心。在催化方面，混合金属CuO基材料(二氧化硅或碳负载，或作为纯混合金属氧化物)将在各种重要的反应中被研究，例如，氢存储介质在液相中的转化为制氢，甘油的选择性氢解。在药物输送方面，我们将主要关注使用介孔有机二氧化硅纳米颗粒(尺寸在30至200 nm之间)，其外表面带有生物相容聚合物(聚乙二醇、蛋白质)的功能化，用于输送和靶向释放抗癌药物(静脉注射)和多肽药物(口服)。预计新的催化剂和治疗设备将带来加拿大涉及能源资源和生产、工业化学、医疗保健和制药或环境修复的各种行业感兴趣的潜在市场技术。

Nanomaterials with well-defined pores in the range of 1-100 nm, i.e. nanopores, are of great interest because of prospects of application in industrial catalysis, environmental remediation, and as biocompatible carriers for drug/gene delivery. Mesoporous materials, in particular, are defined as inorganic frameworks (e.g., silica, metal oxides, carbon) containing periodic arrays of large channels or cages usually comprised between 2 and 15 nm. This range of pore size provides high surface area and high pore volume, making these materials versatile catalysts or catalyst supports and potential hosts/transporters for bioactive substances. The primary objectives of this research program are: 1) to develop new families of highly active and low-cost non-noble metal-based catalysts, to be used for sustainable chemical production and energy-related applications (e.g., H2 production, electrocatalysis); and 2) to design biocompatible nanoporous hybrid materials incorporating desirable functional groups and possessing adequate structure and particle size for biomedical applications (e.g., drug delivery). In addition to synthesis and functionalization, emphasis will be put on assessing the performance of the catalysts and biomaterials and the tuning of the structure-property relationships. Mesoporous silica materials, e.g., MCM-48, SBA-15, can easily be prepared through templating methods combining structure-directing micellar aggregates and inorganic sol-gel process, leading to specific formation of nanopores with well-defined size and shape. These (nano)structures represent an excellent starting point for the design of catalysts and drug delivery systems. Templated mesoporous silicas are considered non-toxic, and chemically and thermally stable. Their surface silanol groups allow fixation of a great diversity of functionalities. Moreover, tailoring of pore structure (size, shape) is possible in order to optimize adsorption and diffusion parameters. Also, morphology and dimension of the material particles can be controlled to form colloidal (nano)spheres or films. Depending on the application targeted, different functionalization approaches will be applied to mesoporous silica (e.g., insertion of metal cations and oxide nanoparticles via impregnation or encapsulation; spatially-selective grafting of organosilanes; conjugation with functional (bio)polymers). Silica-free high-surface-area mixed metal oxide compositions (e.g., Cu, Ni, Mn, Zn, etc.) will also be produced, using the nanocasting process, a method which is based on impregnation of metal salts into the pores of silica, serving as a hard template (followed by silica removal), or by using nanostructured layered hydroxide precursors. In addition to silica and oxides, mesoporous carbon supports will be synthesized both via silica nanocasting and by surfactant-assisted synthesis, and then modified to introduce metal cation/oxide sites. In catalysis, mixed metal CuO-based materials (silica- or carbon-supported, or as pure mixed metal oxides) will be studied in diverse important reactions, e.g., conversion of H2 storage media in liquid phase for H2 production, selective hydrogenolysis of glycerol. For drug delivery, we will mainly focus on using mesoporous organosilica nanoparticles (size between 30 and 200 nm), functionalized with biocompatible polymers (PEG, proteins) on their external surface, for delivery and targeted release of anti-cancer drugs (intravenous) and peptidic drugs (oral delivery). It is anticipated that the new catalysts and therapeutic devices will lead to potentially marketable technologies of interest to a wide variety of Canadian industries dealing with energy resources and production, industrial chemistry, healthcare and pharmaceuticals, or environmental remediation.