Small Naked Pt Nanoparticles Confined in Mesoporous Shell of Hollow Carbon Spheres for High-Performance Nonenzymatic Sensing of H₂O₂ and Glucose

Nonenzyme direct electrochemical sensing of hydrogen peroxide and glucose by highly active nanomaterial-modified electrode has attracted considerable attention. Among the reported electrochemical sensing materials, hollow carbon sphere (HCS) is an attractive carbon support because of its large specific surface area, porous structure, and easy accessibility for target molecules. In this study, naked Pt nanoparticles with average size of 3.13 nm are confined in mesoporous shells of hollow carbon spheres (Pt/HCS) by using one-step synthesis, which can not only produce highly dispersed Pt nanoparticles with clean surface, but also avoid the relatively slow impregnation–reduction process. The surface area of the obtained Pt/HCS (566.30 m² g^–1) is larger than that of HCS, attributing to the enlarged surface area after Pt nanoparticles deposition. The average pore width of Pt/HCS (3.33 nm) is smaller than that of HCS (3.84 nm), indicating the filling of Pt nanoparticles in the mesopores of carbon shells. By using the as-synthesized Pt/HCS as nonenzymatic sensing material, H₂O₂ and glucose can be detected with high sensitivity and selectivity. The linear range toward H₂O₂ sensing is from 0.3 to 2338 μM, and the limit of detection (LOD) is 0.1 μM. For glucose sensing, Pt/HCS exhibited two linear ranges from 0.3 to 10 mM and from 10 to 50 mM with an LOD of 0.1 mM. In addition, the Pt/HCS exhibited higher electrochemical stability than commercial Pt/C in acid solution. The present study demonstrates that Pt/HCS is a promising sensing material for electrochemical detection of both H₂O₂ and glucose.