A new route to the shape-controlled synthesis of nano-sized γ-alumina and Ag/γ-alumina for selective catalytic reduction of NO in the presence of propene.

We report a new route for the direct synthesis of γ-alumina nanocrystals with size and shape control in the presence of oleylamine as the capping agent. Their morphology can be controlled from nanospheres to nanorods by simply tuning a proper amount of concentrated nitric acid (67%) in the synthetic mixture. The as-made nanoparticle products after calcination show γ-alumina nano-size with unique porosity and high specific surface area and retained morphology.

Controlled synthesis of ceria nanoparticles for the design of nanohybrids.

Ceria nanoparticles were synthesized from reaction mixture of cerium nitrate/hexamethylenediamine/water-ethylene glycol. Lamellar, particle-aggregated array, platelet, rice, cube, quasi-sphere shapes of the ceria nanoparticles can be controlled by tuning reaction parameters (reagent concentration, reagent components, pH, and reaction conditions). Studies on shape-dependent catalysis of the bare ceria samples toward CO oxidation indicated that the cube-shaped ceria nanoparticles show better catalytic activity than the nanospheres and the commercial micropowders.