Effect of acid treatment of Corichcore-Ptrich shell/C electrocatalyst on oxygen reduction reaction

Co-rich core-Pt-rich shell/C prepared by thermal decomposition and chemical reduction methods were treated by 20% H2SO4 aqueous solution and used as the electrocatalysts for the oxygen reduction reaction (ORR). The particle size range of Co-rich core-Pt-rich shell (molar ratio of 0.92:1) on carbon powder support decreased from 3-8 to 1-6 nm when the time for the electrocatalysts immersed and treated with 20% H2SO4 aqueous solution increased from 0 to 4 h. Using Co-rich core-Pt-rich shell (molar ratio of 0.92:1)/C treated with 20% H2SO4 from 0 to 4 h as the working electrode, the open circuit potential of ORR in 0.5 M HClO4 aqueous solution increased from 0.9995 to 1.0155 V, and the current density, mass activity, and specific activity at the overpotential of 0.1 V increased from 0.619 mA cm(-2) stop, 6.184 A g(-1) stop, and 18.614 mu A cm(-2) stop to 0.912 mA cm(-2) stop, 15.544 A g(-1) stop, and 23.413 mu A cm(-2) stop, respectively.