TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The capping agent is in contact with the metal particles. The metal particles are formed from a metal selected from Au, Pt, Pd, Ag, Ni, Ru, Rh, Ir, Os, Co, Fe or Cu (preferably Au or Pt) and have a shape selected from spherical, cubical, cylindrical, oval, diamond, polygonal, other regular or irregular three-dimensional shapes. The solid support is a polymer resin, an inorganic hydroxide, an inorganic oxide, a glass bead, a zeolite or a carbon. The inorganic oxide is a metal oxide that contains a metal of Group III - Group XIII (preferably Al2O3, TiO2, Fe2O3, CeO2, CuO, ZnO, SiO2, V2O5, MgO, La2O3, ZrO2, SnO2, MnO2, MoO3, Mo2O5 or zeolites, especially Al2O3, TiO2, Fe2O3 or CeO2). The metal precursor compound is a metal oxide, a metal halide, a metal nitrate, a metal sulfate, a metal sulfide or a hydrate. The metal for the metal precursor compound is Au, Pt, Pd, Ag, Ni, Ru, Rh, Ir, Os, Co, Fe or Cu. The metal compound precursor is LauX4, L2MX2, L2MX4, L3RhX6 or L2M'X6 (preferably HAuCl)4). The reducing agent is a metal hydride, a catalytic hydrogenation system and a metal/acid system. The metal hydride is LiAlH4 or a metal borahydride. The metal borohydride is NaBH4, KBH4, Zn(BH4)2, B2H6, NaBH3CN or Li-S-Bu3BH. For the selective removal method, the catalyst is Au/Fe2O3, Au/TiO2, Au/SiO2, Au/CeO2, Au/Al2O3 and Pt/TiO2.L=H, NH2, K or Na;M=Ni, Pd or Pt;M'=Ru, Ir or Os;X=halide.Preferred Method: The method further involves separating and purifying the catalyst. The catalyst is prepared at a temperature of 0 - 80degreesC. The sonication is generated from a sonication device. In the selective removal of CO, a CO containing gas is passed through the catalysts at a flow rate of 10 - 80 ml/minute and an operating temperature of 0 - 80degreesC. The CO is present in air and is oxidized at a temperature of 0 - 100 (preferably 0 - 25)degreesC in the presence of 70% H2; 70% H2 and 1% O2; H2, CO2 and H2O; or 77% H2, 20% CO2 and 2% O2.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The capping agent is an amino acid, a carboxylic acid, an alkanol, alkanethiol, a cyclodextrin or a polymer (preferably an amino acid). EXAMPLE - An Au catalyst was prepared using HAuCl4 as a precursor, NaBH4 as a reduction agent and amino acid as a capping agent. During the reduction period, sonication was applied for 20 seconds. The catalyst was then separated using centrifuge and washed with deionized water. In this method, low reaction temperature was required. Transmission electron microscopy (TEM) images of the catalyst of Au/TiO2 were observed. The Au colloids were 3 - 5 nm in diameter in the solution. After deposition onto TiO2, there was almost no change in size for Au particles. Also, these Au particles were highly dispersed on the catalyst support. Thus the method is versatile for preparation of many catalysts with high metal particle dispersion.