An alternate aqueous phase synthesis of the Pt3Co/C catalyst towards efficient oxygen reduction reaction

Abstract

AbstractCarbon supported Pt-Co alloys are among the most promising electrocatalysts towards oxygen reduction reaction (ORR) for the application in low temperature fuel cells and beyond, thus their facile and green synthesis is highly demanded. Herein we initially report an alternate aqueous phase one-pot synthesis of such catalysts (containing nominally ca. 20 wt.% Pt) based on dimethylamine borane (DMAB) reduction. The as-obtained electrocatalyst (denoted as Pt3Co/C-DMAB) is compared with the ones obtained by NaBH4 and N2H4·H2O reduction (denoted as Pt3Co/C-NaBH4 and Pt3Co/C-N2H4·H2O, respectively) as well as a commercial Pt/C, in terms of the structure and electrocatalytic property. It turns out that Pt3Co/C-DMAB exhibits the highest ORR performance among all the tested samples in an O2-saturated 0.1 mol/L HClO4, with the mass activity (specific activity) ca. 4 (6) times as large as that for Pt/C. After 10000 cycles of the accelerated degradation test, the half-wave potential for ORR on Pt3Co/C-DMAB decreases only by 4 mV, in contrast to 24 mV for that on Pt/C. Pt3Co/C-NaBH4 or Pt3Co/C-N2H4·H2O shows a specific activity comparable to that for Pt3Co/C-DMAB, but a mass activity similar to that for Pt/C. ICP-AES, TEM, XRD and XPS characterizations indicate that Pt3Co nanoparticles are well-dispersed and alloyed with a mean particle size of ca. 3.4 plusmn; 0.4 nm, contributing to the prominent electrocatalytic performance of Pt3Co/C-DMAB. This simple aqueous synthetic route may provide an alternate opportunity for developing efficient practical electrocatalysts for ORR.