A facile synthesis of CuBi₂O₄ hierarchical dumbbell-shaped nanorod cluster: a promising photocatalyst for the degradation of caffeic acid

The present study reports on the synthesis of Cu-bismuth oxide (CuBi₂O₄)–based nanorods by using a simple co-precipitation method for the photocatalytic degradation of caffeic acid (CA). The incorporation of Cu metal ions during the synthesis of CuBi₂O₄ nanorods might be advantageous to avoid the aggregation and control the leach out of metal ions. The calculated bandgap values of ~ 1.04, 1.02, and 0.94 eV were observed for CuBi₂O₄ with different amounts of Cu 1.0, 0.50, and 0.25 g, respectively. Varying the quantity of Cu metal ions easily tuned the bandgap value within the CuBi₂O₄-based nanorods. However, a further decrease in the bandgap value increased the recombination rate, and the less photocatalyst performance was observed. The CA degradation could be explained based on the species distribution. The CA pKa was mainly located between pKa₁ and pKa₂ of 4.43 and 8.6, respectively. The Cu within the CuBi₂O₄-based nanorods changed the electronic properties and the antibacterial ability. Therefore, the synthesized CuBi₂O₄-based nanorod cluster might be a promising material for the photocatalytic degradation of CA.