Fast photocatalytic degradation of dyes using low-power laser-fabricated Cu₂O-Cu nanocomposites

In this study, we report a simple method to controllably synthesize Cu₂O-Cu nanocomposites by using a low-power CO₂ laser, and application of these nanomaterials for photocatalytic degradation of methylene blue (MB). Our experiments demonstrate that efficient tailoring of the Cu₂O-Cu nanocomposites can be realized by accurate control and optimization of the ambient parameters, such as laser energy and NaOH concentration. Compared to hydrothermally fabricated Cu₂O-Cu catalysts, the laser-reduced composites exhibit better visible-light photocatalytic activity for MB degradation, which could be attributed to the formation of special catalytically active structures on the nanocomposite surface. Under the conditions of 10 mA laser irradiation and 5 M NaOH addition, the fabricated Cu₂O-Cu composites had the highest catalytic activity. The degradation rate of MB is 90.10% after visible-light irradiation for 50 min under the optimum conditions. The as-synthesized Cu₂O-Cu composites showed selective dye degradation, and exhibit relatively higher photocatalytic efficiency for positively charged dyes. This work could lead to facile synthesis of high-performance photocatalysts for fast removal of environmentally hazardous dyes from aqueous solution.