TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises: forming particle comprising a predetermined ratio of atoms of a transition metal and at least one metal of columns IVB, VB, VIB, and VIIB of the periodic table; depositing a contiguous non-noble metal adlayer on a surface of the particles; and replacing the contiguous non-noble metal adlayer with a noble metal. Preferred Components: (I) comprises a core at least partially encapsulated by a shell to form a core-shell particle in which the core and shell have different compositions, and an atomically thin layer of platinum atoms at least partially encapsulating the particle, where at least one of the core or shell is comprised of an alloy formed with at least one element of columns IVB, VB, VIB, and VIIB of the periodic table. The particle comprises an element of titanium (Ti), hafnium (Hf), zirconium (Zr), tungsten (W), tantalum (Ta), niobium (Nb), vanadium (V), rhenium (Re), chromium (Cr), molybdenum (Mo), technetium (Tc), and manganese (Mn). The particle comprises a binary metal alloy comprising a transition metal and a passivating metal (3) having compound of formula (Tr(1-x)Ps(x)). The particle comprises a noble metal. The particle further comprises a non-noble metal. The atomically thin layer of platinum atoms is 1-3 monolayers thick. The particle is a nanoparticle having dimensions of 1-100 nm along three orthogonal directions. The particle is spherical. The core comprises a non-noble metal (2). The shell comprises a noble metal (1). The core-shell particle is spherical. The core or shell comprises an element comprising Ti, Hf, Zr, W, Ta, Nb, V, Re, Cr, Mo, Tc or Mn. The ratio of Pd to Ti is 3:1. The ratio of Pd to Re is 1:1. The contiguous non-noble metal adlayer is Cu, Pb, Bi, Sn, Cd, Ag, Sb or Ti. The noble metal salt consists of potassium tetrachloroplatinate (K2PtCl4).Tr = transition metal, preferably Pd, Ir, and Au;Ps = passivating metal, preferably Ti, W, Nb, Ta, Re, and Ir; andx = the concentration of Ps, being adjustable over the x = greater than 0 to less than 1.Preferred Method: The nanoparticles are formed with at least one metal of Ti, Hf, Zr, W, Ta, Nb, V, Re, Cr, Mo, Tc, and Mn. The particle is formed by dissolving titanium tetrachloride compound (TiCl4(OC5H10)2) powder in dimethyl ether (DME) and mixing the resulting solution with palladium(II) acetate, a thiol, and carbon powder at room temperature. The particle is sonicated, stirred at room temperature for 2 hours, and then dried under hydrogen (H2) atmosphere. The particle is heated to 900 degrees C in an argon (Ar)/H2 atmosphere for 2 hours and cooled to room temperature while maintaining a continuous Ar/H2 flow. The particle is formed by dissolving rhenium chloride complex (ReCl4(OC5H10)2) powder in dimethyl ether (DME) and mixing the resulting solution with palladium(II) acetate, a thiol, and carbon powder at room temperature. The particle is sonicated, stirred at room temperature for two hours, and then dried under an H2 atmosphere. The particle is heated to 600 degrees C or 800 degrees C in H2 atmosphere for three hours and cooled to room temperature while maintaining a continuous H2 flow. The nanoparticles are formed by reducing an aqueous suspension comprising a predetermined ratio of a non-noble metal salt and a salt of at least one metal comprising columns of IVB, VB, VIB, and VIIB of the periodic table to form particle comprising atoms of a non-noble metal and at least one metal of columns IVB, VB, VIB, and VIIB. The method further comprises annealing the nanoparticles to form core-shell nanoparticles comprising a non-noble metal core and a shell comprising at least one metal of columns IVB, VB, VIB, and VIIB of the periodic table. The method further comprises forming a shell of a noble metal on the thus-formed nanoparticles. The nanoparticles are formed by ball milling, atomization of molten metal forced through an orifice at high velocity, centrifugal disintegration, sol-gel processing, or by vaporization of a liquid metal followed by super cooling in an inert gas stream. The contiguous non-noble metal adlayer is deposited by under potential deposition. The contiguous non-noble metal adlayer is replaced by a noble metal by immersing the particles comprising a salt of a noble metal. EXAMPLE - Titanium tetrachloride compound (TiCl4(OC5H10)2) powder was dissolved in dimethyl ether (DME). The resulting solution was mixed with palladium(II) acetate, a thiol, and carbon powder at room temperature. The nominal ratio of palladium to titanium was 3:1 in order to produce palladium-titanium/nanoparticle alloys. The mixture was then sonicated, stirred at room temperature for 2 hours, and then dried under an atmosphere of hydrogen gas. The resulting powder was transferred to an oven at 900 degrees C in an argon/hydrogen atmosphere for 2 hours and cooled to room temperature while maintaining a continuous argon/hydrogen flow.