Chemical methods are generally used for the synthesis of active nanoparticles (metals, semi-metals, metal oxides, and etc) supported on high surface area materials. Chemical methods involve using strong solvents, harmful gases (H2 & CO), and high temperature techniques such as high boiling solvents, calcination and pyrolysis. The main drawbacks of using this approach, is the prevalence of chemical agents on nanomaterials which tends to negate its applications. Alternatively, photochemical and photothermal methods are widely being considered for the synthesis and design of nanomaterials. For these studies, the active nanomaterials incorporated within high surface area materials were prepared by the laser vaporization-controlled condensation (LVCC) technique or by the laser irradiation in solution (LIS) technique. The LVCC technique involves the irradiation of a solid target at the focal point of a laser beam (532 nm, 30 Hz) by the Nd: YAG laser inside a chamber that is sandwiched between two steel plates in the presence of high purity He. Whereas, the LIS technique involves the laser irradiation of chemical precursors in aqueous solvents using an unfocused beam. The LVCC technique was used for the preparation of carbonaceous and N-doped carbonaceous TiO2 support materials from MIL-125(Ti) and NH2-MIL-125(Ti) metal organic frameworks, Ge and GeO2 nanostructures, GeOx/PRGO nanocomposite, and the Fe3O4/PRGO nanocomposite. On the other hand, Pd supported on MIL-125(Ti) and NH2-MIL-125(Ti) nanocatalysts, GeO2/RGO, and the poly(ethylene glycol methacrylate-co-bisacrylamide) hydrogels were all prepared by the LIS technique.

The major objective of the research described in this dissertation is the development of new laser vaporization methods for the synthesis of metal and semiconductor nanoparticles, graphene, B- and N-doped graphene, and metal and semiconductor nanoparticles supported on graphene. These methods include the Laser Vaporization Controlled Condensation (LVCC) approach, which has been used in this work for the synthesis of: (1) gold nanoparticles supported on ceria and zirconia nanoparticles for the low temperature oxidation of carbon monoxide, and (2) graphene, boron- and nitrogen-doped graphene, hydrogen-terminated graphene (HTG), metal nanoparticles supported on graphene, and graphene quantum dots. The gold nanoparticles supported on ceria prepared by the LVCC method exhibit high activity for CO oxidation with a 100% conversion of CO to CO2 at about 60 °C. The first application of the LVCC method for the synthesis of these graphene and graphene-based nanomaterials is reported in this dissertation. Complete characterizations of the graphene-based nanomaterials using a variety of techniques including spectroscopic, X-ray diffraction, mass spectrometric and microscopic methods such as Raman, FTIR, UV-Vis, PL, XRD, XPS, TOF-MS, and TEM. The application of B- and N-doped graphene as catalysts for the oxygen reduction reaction in fuel cell applications is reported. The application of Pd nanoparticles supported on graphene for the Suzuki carbon-carbon cross-coupling reaction is reported. A new method is described for the synthesis of graphene quantum dots based on the combination of the LVCC method with oxidation/reduction sequences in solution. The N-doped graphene quantum dots emit strong blue luminescence, which can be tuned to produce different emission colors that could be used in biomedical imagining and other optoelectronic applications. The second method used in the research described in this dissertation is based on the Laser Vaporization Solvent Capturing (LVSC) approach, which has been introduced and developed, for the first time, for the synthesis of solvent-capped semiconductor and metal oxide nanoparticles. The method has been demonstrated for the synthesis of V, Mo, and W oxide nanoparticles capped by different solvent molecules such as acetonitrile and methanol. The LVSC method has also been applied for the synthesis of Si nanocrystals capped by acetonitrile clusters. The acetonitrile-capped Si nanocrystals exhibit strong emissions, which depend on the excitation wavelength and indicate the presence of Si quantum dots with different sizes. The Si and the metal oxide nanoparticles prepared by the LVSC method have been incorporated into graphene in order to synthesize graphene nanosheets with tunable properties depending on graphene-nanoparticle interactions.