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

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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.