Low Fe-doped Bi_2O_3 photocatalyst with long wavelength response: Crystalline transition and mechanisms by first-principles calculation

摘要

The low Fe-doped Bi_2O_3 with different crystalline phases was synthesized by a solvothermal method. With the increase of annealing temperature, the crystalline phase of the low Fe-doped Bi_2O_3 was transformed from Bi_2O_2CO_3 to monoclinic α-Bi_2O_3 and cubic Bi_(25)FeO_(40). Among them, the mixture of α-Bi_2O_3 and Bi_(25)FeO_(40) (annealed at 600 °C) showed the highest photocatalytic activity for decomposing penta-chlorophenol (PCP) under visible light irradiation (99.2% removal rate). Both theoretical calculations and experimental results support that Fe-doping brings about the hybridization of the energy levels and the modification of electron structure, which is responsible for extending the photoabsorptivity to the visible light region (<623 nm) and strengthening the photocatalytic activity of Fe-doped Bi_2O_3.