Nitrogen-doped carbon dots modified dibismuth tetraoxide microrods: A direct Z-scheme photocatalyst with excellent...

In this work, an all solid direct Z-scheme photocatalyst of monoclinic dibismuth tetraoxide microrods/nitrogen-doped carbon dots (m-Bi₂O₄/NCDs) has been constructed through a simple one-step hydrothermal method. The m-Bi₂O₄/NCDs photocatalyst exhibits excellent photocatalytic activity for the degradation of methylene orange (MO) and phenol under visible light irradiation. The pollutants of MO (10 mg L^-1) and phenol (45 mg L^-1) could be efficiently degraded by m-Bi₂O₄/NCDs within 30 and 120 min, respectively, which is much better than that of the single m-Bi₂O₄, indicating that the introduction of NCDs into m-Bi₂O₄ can effectively improve the photocatalytic activity. Moreover, the m-Bi₂O₄/NCDs photocatalyst possesses a high photocatalytic stability and durability, and its photocatalytic activity did not show obvious decline after four photodegradation cycles. It is found that both O₂^- and direct h⁺ oxidation play important roles in the degradation process, and based on the experimental result a direct Z-scheme photocatalytic mechanism is proposed. This study suggests that the as-prepared m-Bi₂O₄/NCDs composite is a promising photocatalyst for environmental remediation.