Preparation and Electrocatalytic Performance of Thin―shell Ni/Pt Core―shell Nanoparticles

The Ni/Pt core―shell nanoparticles with different shell thicknesses were prepared by composite coating of colloid particles and then characterized by HRTEM, EDS, XPS and XRD. Electrochemical properties for the oxygen electro―reduction reaction and methanol electro―oxidation were measured by potentiodynamic and cyclic voltammetry. The experimental results show that Ni/Pt core―shell nanoparticles are spherical and the mean particle size of Ni1―Pt0.067 is about 7 nm with shell thickness of 1 nm. Compared with Pt/C, Ni/Pt core―shell nanoparticels possess higher activity. Ni1―Pt0.067/C has the highest catalytic activity in these prepared catalysts with different thickness, and its peak current density can reach 143.06 mA/mg in 0.5 mol/L H2SO4 solution, 1.4 times of that of Pt/C for O2 electro―reduction reaction. Peak current density of Ni1―Pt0.067/C for methanol electro―oxidation reaches 538.3 mA/mg in 0.5 mol/L H2SO4+1.0 mol/L CH3OH solution, which is 5.2 times of that of Pt/C. Based on 1mg Pt, the specific mass activity of Ni1―Pt0.067/C is 30―fold higher than that of Pt/C nanoparticles.