TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The composition further comprises a base metal compound comprising base metal hydroxides, base metal oxides and/or base metal carbonates, and a reducing agent. Preferred Components: The precious metal precursor compound: has a low water solubility of 0.0001-0.1 mole/l (as determined at 22 degrees C); and is dihydrogenhexahydroxo-(IV) platinate, palladium hydroxide, iridium (IV) hydroxide (all preferred), a precious metal hydroxide, a precious metal hydroxo complex, a hydrated oxide of a precious metal, silver hydroxide, silver(I) oxide (Ag2O.nH2O), gold(III) hydroxide, platinum(IV) oxide (PtO2.nH2O), palladium(II) oxide (PdO.nH2O), iridium trihydroxide, iridic acid (H2Ir(OH)6), iridium oxide (Ir2O3.nH2O), iridium(IV) oxide (IrO2.nH2O), Ruthenium(III) hydroxide, ruthenium(III) oxide (Ru2O3.nH2O), rhodium hydroxide, and/or rhodium hydroxide (Rh2O3.nH2O), where n is 0.1-10. The precious metal of the precursor compound comprises platinum, palladium, iridium (all preferred), rhodium, ruthenium, gold, and/or silver. The base metal is cobalt(II) hydroxide, nickel(II) hydroxide, copper(II) hydroxide, manganese(II) hydroxide, chromium(III) hydroxide, cobalt(II) oxide, nickel(II) oxide, copper(I) oxide, copper(II) oxide, manganese(II) oxide, manganese(IV) oxide, chromium(III) oxide, cobalt(II) carbonate, nickel(II) carbonate, copper(II) carbonate, manganese(II) carbonate, and/or chromium(III) carbonate. The nano-sized precious metal particles have an average particle size of 0.5-100 nm, preferably 2-20 nm (as detected by transmission electron microscopy). The colloidal dispersion further comprises the electrically conductive and/or electrically non-conductive support materials, and is free from additional components such as surfactants, inorganic salts, halide ions, mineral acids or other anionic or cationic species. The electrically conductive support material comprises carbon black powders, graphitized carbon blacks, carbon nanotubes, carbon nanohorns, graphenes, carbon platelets, carbon fibers, electrically conductive ceramic powders, ceramic nanotubes, electro-conductive polymer materials, alumina, silica, titania, ceria, zirconia, calcium carbonate, and/or barium sulfate. The electrically conductive support material is a supported platinum or platinum alloy catalyst.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The reducing agent is an aliphatic alcohol consisting of methanol, ethanol, 1-propanol, iso-propanol and/or 1-butanol. The acidic ionomer is an acidic perfluorinated ionomer compound consisting of sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, bis-sulfonyl imide groups of formula (Rf1-SO2-NH-SO2-R1af), bis-carbonyl imide groups of formula (Rf1-CONH-CO-R1af) and/or sulfonyl-carbonyl imide groups (Rf1-SO2-NH-CO-R1af).Rf1, R1af = fluorine-containing carbon chains.Preferred Method: The reduction process is carried out for a time period of 1-120 hours at a temperature of 5-40 degrees C, preferably 20-25 degrees C. The steps (a) and (b) are conducted separately, or simultaneously within a time period of 1-120 hours, preferably 1-48 hours. EXAMPLE - Typical composition comprised of: 0.68 wt.% of platinum; and 19.8 wt.% of ionomer.