Hydrothermal Synthesis and Electrochemical Properties of Urchin-Like Core−Shell Copper Oxide Nanostructures

Urchin-like core−shell CuO assembled by closely packed nanorods with a diameter of 10 nm has been hydrothermally synthesized in assistance of poly(ethylene glycol) (PEG) at 100 °C for 10 h. HRTEM image shows that the diameter of the inner core is ∼1.5 μm and that of the outer shell is ∼2 μm. Control experiments run at different temperature indicate that higher temperature than 100 °C results in the outer shell consisting of particles and blocks of different size and lower temperature gains no products. According to the 2 and 18 h reaction results, PEG plays two important roles in the construction of the core−shell urchin-like structure: the stabilization from the hydrocarbon chain to prolong the lifetime of Cu(OH)2 and the passivation to the lateral surfaces of the nanorods. The as-prepared CuO with a core−shell urchin-like structure exhibits wide biosensor capability toward H2O2 with a linear response in the concentration ranging from 10 μM to 5.55 mM.