Copper nanoparticles have been prepared by the solvated metal atom dispersion (SMAD) method. Oxidation of the SMAD prepared copper colloids resulted in Cu@Cu(2)O core shell structures (7.7 +/- 1.8 nm) or Cu(2)O nanoparticles depending on the reaction conditions. The nano Cu, Cu@Cu(2)O core shell, and Cu(2)O particles were found to be catalytically active for the generation of hydrogen from ammonia-borane either via hydrolysis or methanolysis reaction.

Ammonia-borane (AB) hydrolysis for the generation of hydrogen has been studied using first row transition metal ions, such as Co (2+), Ni (2+), and Cu (2+). In the cases of cobalt- and nickel-assisted AB hydrolysis, amorphous powders are formed that are highly catalytically active for hydrogen generation. Annealing of these amorphous powders followed by powder X-ray diffraction measurements revealed the presence of Co(0) and Co 2B and Ni(0) and Ni 3B, respectively. On the other hand, copper-assisted AB hydrolysis was catalyzed by in situ generated H (+) and Cu(0) nanoparticles. The reduction ability of AB for the realization of coinage metal nanoparticles from the respective metal salts has also been studied. These reduction reactions were found to be facile, affording colloids of pure metal nanoparticles. Nanoparticles prepared in this manner were characterized by UV-visible spectroscopy and high-resolution electron microscopy.

Pyrdine incorporation into the covalent organic framework COF-1 resulted in a highly dense packing structure in which the pyridine occupies the hexagonal pore space between the COF layers. This optimizes pore aperture for quantum sieving of hydrogen isotopes and introduces flexibility at cryogenic temperatures into the system. The separation factor (S D 2 /H 2 ) is about 10 at 22 K, which is the highest reported to date. Chem. Asian J.

Three-dimensional covalent organic frameworks (COFs) have been demonstrated as a new class of templates for nanoparticles. Photodecomposition of the [Pd(η(3)-C(3) H(5))(η(5)-C(5)H(5))]@COF-102 inclusion compound (synthesized by a gas-phase infiltration method) led to the formation of the Pd@COF-102 hybrid material. Advanced electron microscopy techniques (including high-angle annular dark-field scanning transmission electron microscopy and electron tomography) along with other conventional characterization techniques unambiguously showed that highly monodisperse Pd nanoparticles ((2.4±0.5) nm) were evenly distributed inside the COF-102 framework. The Pd@COF-102 hybrid material is a rare example of a metal-nanoparticle-loaded porous crystalline material with a very narrow size distribution without any larger agglomerates even at high loadings (30 wt %). Two samples with moderate Pd content (3.5 and 9.5 wt %) were used to study the hydrogen storage properties of the metal-decorated COF surface. The uptakes at room temperature from these samples were higher than those of similar systems such as Pd@metal-organic frameworks (MOFs). The studies show that the H(2) capacities were enhanced by a factor of 2-3 through Pd impregnation on COF-102 at room temperature and 20 bar. This remarkable enhancement is not just due to Pd hydride formation and can be mainly ascribed to hydrogenation of residual organic compounds, such as bicyclopentadiene. The significantly higher reversible hydrogen storage capacity that comes from decomposed products of the employed organometallic Pd precursor suggests that this discovery may be relevant to the discussion of the spillover phenomenon in metal/MOFs and related systems.

Designing and developing ideal catalyst paves the way to green chemistry. The fields of catalysis and nanoscience have been inextricably linked to each other for a long time. Thanks to the recent advances in characterization techniques, the old technology has been revisited with a new scope. The last decade has witnessed a flood of research activity in the field of nanocatalysis, with most of the studies focusing on the effect of size on catalytic properties. This led to the development of much greener catalysts with higher activity, selectivity and greater ease of separation from the reaction medium. This Minireview describes the emerging trends in the field of nanocatalysis with implications towards green chemistry and sustainability.