Short-Time Hydrothermal Synthesis of CuBiO Nanocolumn Arrays for Efficient Visible-Light Photocatalysis.

In this article, a short-time hydrothermal method is developed to prepare CuBiO nanocolumn arrays. By using Bi(NO)·5HO in acetic acid and Cu(NO)·3HO in ethanol as precursor solutions, tetragonal CuBiO with good visible light absorption can be fabricated within 0.5 h at 120 °C. Tetragonal structured CuBiO can be formed after 15 min hydrothermal treatment, however it possesses poor visible light absorption and low photocatalytic activity. Extending the hydrothermal treatment duration to 0.5 h results in a significant improvement invisible light absorption of the tetragonal CuBiO. The CuBiO obtained through 0.5 h hydrothermal synthesis shows a band gap of 1.75 eV and exhibits the highest photocatalytic performance among the CuBiO prepared with various hydrothermal time. The removal rate of methylene blue by the 0.5 h CuBiO reaches 91% under visible light irradiation for 0.5 h. This study proposes a novel strategy to prepare photoactive CuBiO nanocolumn arrays within 0.5 h at a moderate temperature of 120 °C. The hydrothermal method provides a facile strategy for the fast synthesis of metal-oxide-based photocatalysts at mild reaction conditions.