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 1 mg Pt, the specific mass activity of Ni1-Pt0.067/C is 30-fold higher than that of Pt/C nanoparticles.