TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Metallic Particles: Less than 20% of the metallic particles have a particle size of 5 nm or more.When the metallic particles have average particle size of 3 nm or less, less than 20% of the metallic particles have particle size of 4 nm or more.When the metallic particles have average particle size of 1-2 nm, less than 20% of the metallic particles have particle size of 3 nm or more and less than 20% of the metallic particles have particle size of less than 1 nm.When the metallic particles have average particle size of 1 nm, less than 20% of the metallic particles have particle size of 2 nm or more and less than 20% of the metallic particle have particle size of less than 1 nm.The metallic particles have a surface area of at least 50 m2/g and are in the form of free metal or metallic compound.The metal is chosen from iron, cobalt, magnesium, nickel, titanium, chromium, copper, platinum, gold, silver, rhodium, ruthenium, palladium and/or iridium.Preferred Composition: The metallic aerogel composition comprises 0.1-80 wt.% of metallic particles, and also comprises a polymer electrolyte, and is in the form of a particle, film or fiber.Preferred Aerogel: The aerogel has surface area of 100-2000 m2/g, pore volume of 0.5-10 cm3/g and density of 0.01-2 g/cm3, and comprises carbon, and oxide(s) chosen from silica, alumina, titania, vanadia, niobia, zirconia and/or tantala.Preferred Compound: The metallic compound is organometallic compound chosen from dimethyl(cyclooctadiene)platinum (II), tetraamine platinum (II) chloride, platinum (II) hexafluoroacetylacetone, (trimethyl)methylcyclopentadienylplatinum (IV), bis(cyclopentadienyl)ruthenium, bis(ethylcyclopentadienyl)ruthenium (II), bis(methylcyclopentadienyl)ruthenium, and/or (methylcyclopentadienyl)(1,5-cyclooctadiene)iridium (I).Preferred Process: The metallic aerogel composition is heated at 50-2000 degrees C to reduce the metallic compound to the free metal.At least two monomers are polymerized in a liquid medium to form a polymerization product comprising a hydrogel sol and the liquid medium.The hydrogel sol is cured to form a cured hydrogel.At least a portion of the liquid medium is removed from the cured hydrogel to form an organic hydrogel.The organic hydrogel is pyrolyzed at 400-2000 degrees C to form a pyrolyzed aerogel.The pyrolyzed aerogel is contacted with a supercritical fluid comprising metallic compound to form a metallic aerogel.The metallic aerogel is reduced to form a reduced metal aerogel.Alternately, at least two monomers are polymerized in liquid medium and in the presence of metallic compound to form polymerization product comprising hydrogel sol and liquid medium.The hydrogel sol is cured at 50-200 degrees C to form cured hydrogel.At least a portion of the liquid medium is optionally removed from the cured hydrogel to form a dried aerogel.The dried aerogel or the cured aerogel is contacted with a first supercritical fluid to form organic aerogel.The organic aerogel is pyrolyzed to form pyrolyzed aerogel.The pyrolyzed aerogel is optionally contacted with second supercritical fluid to form metallic aerogel.The metallic aerogel is reduced to form reduced metal aerogel.At least one of first supercritical fluid or second supercritical fluid comprises metallic compound. The metallic aerogel is further contacted with the polymer electrolyte.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Fluid: The supercritical fluid used in the formation of metallic aerogel composition is carbon dioxide, ethane, propane, butane, pentane, dimethyl ether, ethanol and/or water. EXAMPLE - Resorcinol (in grams) (2) was dissolved in water (2.38). Subsequently, sodium carbonate (0.019) and formaldehyde solution (2.95) were added. The contents were mixed and kept at room temperature for 1 day, at 50 degrees C for 1 day and at 90 degrees C for 3 days. The monolith obtained was immersed in acetone (200 ml) and kept for 2 days. Subsequently, acetone was extracted supercritically. Supercritical carbon dioxide extraction was performed followed by depressurization to obtain aerogel (2.9). The aerogel in powder form had BET surface area of 888 m2/g, pore volume of 1.24 cm3/g and average pore diameter of 5.5 nm, and in large-piece form had BET surface area of 873 m2/g, pore volume of 1.49 cm3/g and average pore diameter of 6.3 nm. The aerogel in monolithic form was placed in a quartz tube which was placed in tubular oven. One end of the tube was connected to a nitrogen cylinder and the other end of the tube was connected to a soap bubble meter to measure the flow rate of nitrogen. The flow rate of nitrogen was controlled using a needle valve placed after the regulator and adjusted to 100 cm3/minute. The oven was heated to 1000 degrees C under flowing nitrogen, and the heating rate was approximately 5 degrees C/minute. The temperature inside the oven reached 1020 degrees C in approximately 6 hours. The oven was kept at this temperature for another 5 hours. Subsequently, the oven was turned off and cooled overnight with nitrogen flowing. The material removed from the tube was black and its size appeared to have shrunk compared to the original material. The carbon aerogel obtained had BET surface area of 741 m2/g, pore volume of 0.77 cm3/g and average pore diameter of 3.4 nm.