One-dimensional shape-controlled preparation of porous Cu2O nano-whiskers by using CTAB as a template

One-dimensional (1D) cuprite (Cu₂O) nano-whiskers with diameter of 15-30 nm are obtained from liquid deposition method at 25 °C by adding a surfactant, cetyl trimethyl ammonium bromide (CTAB), as a template. TEM and HRTEM show that the nano-whiskers exhibit a well-crystallized 1D structure of more than 200 nm in length, and confirms that the nano-whiskers grow mainly along the 〈111〉 direction. Moreover, there are many pores in the nano-whiskers, which is beneficial for the photocatalysis under visible light. When polyethylene glycol (PEG), glucose and sodium dodecylbenzenesulfonate (SDS) are used as templates, 1D structures cannot be obtained. According to the TEM images of the compound obtained at different stages during the growth of the Cu₂O nano-whiskers, it is found that the role of CTAB is to interact with tiny Cu(OH)₂, which can adsorb OH⁻ and become negative charged, to disperse the tiny Cu(OH)₂ solid and to induce the growth of Cu₂O along the 1D direction. Although CTAB is significant for the preparation of the 1D nanomaterials, ion character of the precursor (Cu(OH)₂·OH⁻ or Cu²⁺) is important as well since there is no nano-whiskers obtained with Cu²⁺ as the precursor. Moreover, the probable mechanism of the formation for the porous structure is discussed.