Hollow PtNi Nanochains as Highly Efficient and Stable Oxygen Reduction Reaction Catalysts

Abstract

AbstractDesign of electrocatalysts with both enhanced electrochemical activity and high durability is the key challenge in the development of proton exchange membrane fuel cells (PEMFCs). Herein, hollow platinum nickel nanochains (H‐PtNi NCs) were synthesized by the galvanic displacement of Ni nanowires (Ni NWs) and subsequent acid etching, and used for oxygen reduction reaction (ORR). H‐PtNi NCs have outer diameter of 50–100 nm, length of 0.5‐10 μm, and the average thickness of Pt layer around 4.5‐7.5 nm. In a typical process, H‐PtNi NCs/C were prepared on carbon support, and these unique structural features endow the H‐PtNi NCs/C with a mass activity of 4.6 A mg−1 and a specific activity of 11.45 mA cm−2 at 0.9 V versus reversible hydrogen electrode, respectively, 18 times and 29 times higher than the commercial Pt/C. Moreover, the H‐PtNi NCs/C is also very stable with negligible activity decay over the course of 50000 cycles. This high apparent activity can be attributed to the high intrinsic activity originated from abundant active sites of the open ends and the inner/outer surfaces as well as the structural disorder of hollow nanochains with surface roughness.