The reaction between tetrachlorosilane and 4, 4'-dihydroxydiphenylsulfone with magnesium oxide as a base yielded a three-dimensional alternative silane-O-diphenylsulfonyl hybrid copolymer, of which shapes was sphere with a diameter of 200 nm. The calcination of the copolymer under vacuum gave spherical silica-carbon cluster composite with a diameter of 200 nm, of which average specific surface area was 92.0m2/g. The treatment of the calcinated product with an aqueous NaOH solution yielded a spherical carbon cluster containing a small amount of silica, of which average specific surface area was 1026.9m2/g. The alkali-treated composite material absorbed CO2 twice as much as a commercial active carbon. The palladium-loaded alkali-treated composite material absorbed H2 6 times as much as a commercial active carbon.
Gold-dendrimer nanocomposites were prepared in the presence of poly (amidoamine) (PAMAM) dendrimer (generation 3, 3.5, 5, and 5.5) or poly (propyleneimine) (PPI) dendrimer (generation 3 and 4) via reduction of HAuCl4 with sodium borohydride. The average particle sizes of the gold nanoparticles were independent of the dendrimer concentration as well as the dendrimer generation, ranging between 3.0 and 4.3 nm in diameter for PAMAM dendrimers and between 2.1 and 2.3 nm in diameter for PPI dendrimers. The catalytic activities of the gold-dendrimer nanocomposites upon elimination of hydroxyl radicals formed in an H2O2/FeSO4 system was examined using a spin-trapping method. The catalytic activity of gold-PPI dendrimer nanocomposites was slightly lower than that of gold-PAMAM dendrimer nanocomposites. In addition, the gold-dendrimer nanocomposites exhibited high catalytic activities which were hardly affected by the concentration as well as the generation of the dendrimer except PAMAM dendrimer 3.5. The highest activity for the gold-PAMAM dendrimer G3.5 nanocomposites was 85 times that of ascorbic acid.
Boehmite-treated aluminum foil was colored by a platinum coating, and its mechanism of coloring was investigated. Hydrated aluminum (boehmite (Al00H)) was generated on the surface of aluminum foil. The color of the boehmite-treated surfaces did not change the metallic luster of the aluminum foil surface with treatment time. However, when the boehmite-treated aluminum foil surfaces were coated with platinum by magnetron sputtering, the color of the surface changed to several different colors based on the hydration time. This coloring mechanism was investigated by observation of surface structures and simulations of the reflectance of multilayer film interference. Boehmite develops as a porous needle shaped film on the aluminum surface. The deposited platinum coating is deposited in a similar manner. Therefore, the coloring mechanism of the boehmite films is thought to be due to the interference of multilayer films with varying degrees of thickness.