Zigzag PtCo nanowires modified in situ with Au atoms as efficient and durable electrocatalyst for oxygen reduction reaction

Abstract

Pt-based nanowires are often used as efficient electrocatalysts for oxygen reduction reaction (ORR) but limited by poor stability. Herein, we prepare zigzag PtCo nanowires (PtCo NWs) by a facile one-pot method, and then modify their surface in situ with Au atoms through galvanic replacement and annealing process. The mass activity of as-prepared PtCoAu1.5 NWs (the Au/Pt atomic ratio is 1.5%) reaches 1.94 A mgPt−1, which is about 11 times higher than that of commercial Pt/C, attributing to the integrated advantages of ultrathin nanowire structure, high-index facets, and alloy effect. And the surface modification by trace Au atoms can suppress the leaching of Co atoms and preserve the nanowire structure without agglomeration. The PtCoAu1.5 NWs behave improved stability (only 21% mass activity loss) after 20,000 potential cycles in half-cell test, compared to PtCo-T NWs (35%) and Pt/C catalysts (59%). In single-cell test, the PtCoAu1.5 NWs also show improved stability compared to PtCo-T NWs and Pt/C catalyst. This work provides a strategy to further improve the performance of Pt-based catalysts for fuel cells.