Surface Composition and Lattice Ordering-Controlled Activity and Durability of CuPt Electrocatalysts for Oxygen Reduction Reaction

We report the enhanced activity and stability of CuPt bimetallic tubular electrocatalysts through potential cycling in acidic electrolyte. A series of CuPt tubular electrocatalysts with sequential increased lattice ordering and surface atomic fraction of Pt were designed and synthesized by thermal annealing to reveal their improved electrocatalytic properties. These low-Pt-content electrocatalysts with Pt shell are formed through the thermal annealing and following potential cycling treatment. The catalysts (C1) with a low atomic fraction of Pt on the surface and low lattice ordering in the bulk are treated in acidic electrolyte, resulting in the formation of a Pt shell with relatively low activity and stability. However, the catalysts (C2) with a Pt-rich surface and high lattice ordering have a highly enhanced electrochemical surface area after potential cycling via surface roughing. The rough Pt shell of the C2 catalysts is achieved by leaching of surface Cu and the concomitant morphology restructuring....