Structural characteristics and thermal stability of Pt-Ni nanoparticles

The Monte Carlo and molecular dynamics simulations were carried out for the Pt-Ni nanoparticles using the angular-dependent potential. The effects of composition, size and temperature on the structural characteristics and thermal stability of Pt-Ni nanoparticles were systematically studied. It is found that with the increase of x , the Pt concentration in each shell of Pt x Ni 1- x nanoparticles gradually increases. The Pt atoms are dispersed, and compositional oscillations occur between the shells. The result of element segregation depends on the combined action of bond energy, strain energy, surface energy and interface energy. Pt content on the surface declines with the increase of size or temperature. With the rise of x , the melting point of Pt x Ni 1- x nanoparticles with the same size and shape first ascends, then descends around x = 0.125, and then rises again around x = 0.5. The effect of Pt doping on the catalytic performance of Ni nanoparticles in methane dry reforming was discussed.