NOVELTY - Catalyst particles having a core-shell-shell structure in the form of (NM-ZS-EM), which is constructed in layers and in which NM is a non-noble metal core (1) of the particle, EM is a noble metal forming outer shell (3), and ZS is an intermediate layer (2) which is arranged between the non-noble metal core and the outer noble metal shell, and comprises a non-noble metal-noble metal alloy (I), is claimed. The atomic ratio of the non-noble metal and the noble metal in the intermediate layer gradually decreases from the non-noble metal core in the direction of the noble metal forming outer shell.    USE - The catalyst particles are useful in gas phase catalysis, in an electrocatalyst for fuel cells, in a catalyst for automobiles, and in electronic- or medical applications (all claimed).    ADVANTAGE - The catalyst particles exhibit high efficiency even at low platinum loadings. The method is simple, economic and environmentally friendly.    DETAILED DESCRIPTION - Catalyst particles having a core-shell-shell structure in the form of (NM-ZS-EM), which is constructed in layers and in which NM is a non-noble metal core (1) of the particle, EM is a noble metal forming outer shell (3), and ZS is an intermediate layer (2) which is arranged between the non-noble metal core and the outer noble metal shell, and comprises a non-noble metal-noble metal alloy of formula ((NM)x(EM)y) (I), is claimed. The atomic ratio of the non-noble metal and the noble metal in the intermediate layer gradually decreases from the non-noble metal core in the direction of the noble metal forming outer shell.    Either x = 0.99-0.01; and    y = 0.01-0.99; or    x+y = 1.    INDEPENDENT CLAIMS are also included for:    (1) preparing the catalyst particles, comprising (A) heating a non-noble metal precursor compound in a polyol solvent at 80-120 degrees C, (B) heating the obtained reaction solution to 200-240 degrees C for forming the non-noble metal core particles, (C) adding a noble metal precursor compound to the reaction solution at 150-190 degrees C for forming the intermediate layer and the outer shell, and (D) cooling the reaction mixture and isolating the particles; and    (2) a catalyst composition for electrochemical applications, comprising the above catalyst particles.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the catalyst particles.    Non-noble metal core (1)    Intermediate layer (2)    Outer shell (3)