Controlling the electronic structure of a catalyst has become an important approach to tune and optimize its antipoisoning ability and catalytic efficiency for a chemical reaction. Using d-mannitol as a structure-directing agent to induce size transformation and twinned defects in copper particles, penta-twinned Cu elongated pentagonal bipyramids as supports have been synthesized, and HAuCl4 is reduced in situ to form an AuCu alloy on the surface of Cu, generating a self-supporting AuCu@Cu core-shell structure for application as a glucose sensor in a neutral medium. The AuCu@Cu elongated pentagonal bipyramids with 0.42 at% Au show activities comparable with the Au and Pt catalyst but are more tolerant toward Cl- than Au and more tolerant toward H3-xPO4x- than Cu. The mass activity of AuCu@Cu reaches 0.10 A mg(-1) of Au at 0.6 V versus Ag/AgCl (3 m KCl) in a pH 8.0 buffer. The self-supporting AuCu@Cu elongated pentagonal bipyramids are promising catalysts for glucose sensing in a neutral medium. This work offers an effective way to design antitoxic and durable catalysts with ultralow content of noble metal for glucose sensing.