TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The core metal nanoparticle comprises a metal with a melting point of less than 400 degrees C. The core metal nanoparticle comprises a metal comprising indium, gallium, germanium, tin, antimony, thallium, lead, bismuth, zinc, cadmium and/or mercury with low melting point. The non-aqueous solution comprises ionic liquid at room temperature. The non-aqueous solvent is ionic liquid with cation and anion at room temperature. The cation comprises ammonium ion of formula (R4-N+(R1)(R3)(R2), (R1-P+(R1)(R3)(R2)), (R1-S+(R2)(R3)), pyrrolidinium of formula (II), piperidinium of formula (III), 1H-imidazol-3-ium of formula (IV) or pyridinium of formula (V), preferably tetrafluoroborate, tetracyanoborate, (trifluoromethyl)trifluoroborate, pentafluoroethyltrifluoroborate, trifluoro(eptafluropropyl)borate, trifluoro (nonaflurobutyl) borate, (pentafluorophenyl ethane) trifluorophosphate, trifluoroacetate, trifluoromethanesulfonate, ethyl sulfate, dicyanamide, tricyanomethanide, thiocyanate ion, selenocyanogen, copper(II) chloride, tetrachloroaluminate, tetrachlorozincate, (2,2,2-trifluoroacetyl)(trifluoromethylsulfonyl)amide, bis(fluorosulfonyl)amide or hydrogen fluoride of formula (F(HF)23). The platinum alloy precursor comprises potassium hexachloroplatinate(IV), potassium tetrachloroplatinate(II), brom platinous acid, platinum(II) nitrate and/or platinum-acetylacetonateR1-R3 = 1-20C alkyl or 2-20C alkyl ether.Preferred Method: The core metal nanoparticles are formed by sputtering a metal in the non-aqueous solvents. The platinum or platinum alloy is deposited on the metal nanoparticles with low melting point by contacting the nanoparticles with platinum or platinum alloy precursor. EXAMPLE - Indium was sputtered on imidazolium-based ionic liquid with tetrafluoroborate anion, which was applied to a glass surface, under an argon atmosphere at a rate of 20 mA/cm2 to obtain low melting point metal (LMPM) nanoparticles. Potassium hexachloroplatinate(IV) or mixture of potassium hexachloroplatinate(IV) and cobaltous nitrate hexahydrate was coated on the imidazolium based ionic liquid with tetrafluoroborate anion. The resulting solution was reduced through rinsing with 5% hydrogen in argon gas at 80 degrees C for 1 hour for the deposition of platinum or platinum-cobalt layer on the nanoparticles. The LMPM core was removed by heating the solution above the melting point of the indium metal core.