Ternary PtCoMo Alloy with Dual Surface Co and Mo Defects for Synergistically Enhanced Acidic Oxygen Reduction

Graphical Better with defects : A ternary alloy PtCoMo nanocatalyst with dual surface Co and Mo vacancy defects was used as an efficient electrocatalyst for acidic oxygen reduction reaction for fuel cell applications. Proton exchange membrane fuel cell (PEMFC) is considered as the most promising energy conversion technology, which is hampered by the unsatisfied activity and high loading of Pt. The performance of Pt-based catalyst toward PEMFC depends on the surface bond length of Pt−Pt, which is closely related to the surface defect engineering. Here we firstly present a ternary alloy PtCoMo nanocatalyst with dual surface Co and Mo vacancy defects (V Co−Mo −PtCoMo) that compressed the Pt−Pt bonds, thus exhibiting an outstanding activity toward oxygen reduction reaction (ORR) with a mass activity of 0.57 A mg Pt −1 at 0.9 V (RHE, reversible hydrogen electrode), which is 5.2 times higher as compared with commercial Pt/C (20 wt %) in 0.1 M HClO 4 . The characterizations and density functional theory calculations demonstrate that the Pt−Pt bonds are significantly compressed through the dual surface defects, thus weakening the binding energy and effectively enhancing the acidic ORR performance.