General Synthesis of Large-Scale Arrays of One-Dimensional Nanostructured Co₃O₄ Directly on Heterogeneous Substrates

We have developed a general two-step synthesis of large-scale arrays of one-dimensional (1D) nanostructured Co 3 O 4 directly on various substrates. Throughout a controllable hydrothermal process using urea as mineralizer and hereafter with a postcalcination process under air atmosphere, Co 3 O 4 1D nanostructure arrays have been grown firmly on insulating substrates, such as glass slides and ceramics, which is quite convenient for the construction of gas sensor devices without any extra electrode preparation process. Furthermore, this direct-growth approach can be readily extended to conductive substrates (ITO, Ti, Fe−Co−Ni alloy), and meanwhile due to the robust mechanical adhesion and one-dimensional carrier transportation architecture firmly contacted to the metal, the metal substrate-supported Co 3 O 4 arrays could act as a promising electrode material and be straightforwardly integrated into electronic and electrochemical nanodevices.