Photocatalytic Degradation of 4-Chlorophenol by Gd-Doped β-Bi2O3 Under Visible Light Irradiation

Abstract

Chlorophenols are known as persistent organic pollutants. Therefore, research on the removal of chlorophenols has attracted widespread attention. Herein, the photocatalytic degradation of 4-chlorophenol by Gd-doped β-Bi2O3 under visible light irradiation was studied. The results showed that Gd-doped β-Bi2O3 materials are efficient catalysts for the photocatalytic degradation of chlorophenols, and 2%(atomic fraction) Gd-doped β-Bi2O3 exhibits the highest photocatalytic activity for 4-chlorophenol degradation, because doping an appropriate amount of Gd3+ ions can effectively reduce the recombination rate of the photogenerated e‒/h+ pairs and then enhance the photocatalytic performance. When the reaction was carried out at 25 °C for 6 h using the 2% Gd-doped β-Bi2O3 micro/nano materials of 200 mg and at air flow rate of 40 mL/min, the degradation rate of 4-chlorophenol reached 92.3%. Additionally, based on the analysis of the products, it was speculated that the dominant photocatalytic degradation mechanism of 4-chlorophenol by Gd-doped β-Bi2O3 under visible light irradiation is an oxidative process involving an attack by the hydroxyl radical.