Enhanced photocatalytic degradation of methylene blue by nanocomposites prepared by laser ablation of Bi on CNT-α-Fe₂O₃ nanoparticles

The low conductivity and high combination rate of photogenerated electrons (e-) and photogenerated holes (h+) are the real challenges of photocatalysis. These problems could be mitigated by the synthesis of heterostructured nanocomposites (NCs). In this study, Bi@CNT-Fe₂O₃ nanocomposite was fabricated via pulsed laser ablation in liquid and characterized by UV–Vis spectroscopy, photoluminescence (PL), X-ray diffraction (PXRD) and field scanning electron microscopy (FESEM). These techniques revealed successfully the formation of CNT-α-Fe₂O₃ and Bi@CNT-α-Fe₂O₃ nanocomposites. The photocatalytic activities of the Fe₂O₃, CNT-α-Fe₂O_3, and Bi@CNT-Fe₂O₃ photocatalysts were evaluated by the degradation of methylene blue (MB) dye under ultraviolet (UV) light irradiation in the presence of a very low concentration of hydrogen peroxide (H₂O₂) as an oxidizing agent. The results show that the Bi@CNT-α-Fe₂O₃ NC has the highest photocatalytic degradation efficiency of MB which completes in 20 min of UV light irradiation. In addition, the obtained rate constants (min⁻¹) of Bi@CNT-α-Fe₂O₃ NC were 1.3 and 3.4 times higher than those of CNT-α-Fe₂O₃ and α-Fe₂O_3. nanocatalysts, respectively.