Hyper oxygen incorporation in CeF3: a new intermediate-band photocatalyst for antibiotic degradation under visible/NIR light

Abstract

Intermediate-band semiconductors perform functions similar to natural photosynthesis by combining two photons to achieve a higher electron excitation. In this study, a strategy was developed to prepare a high oxygen-doped CeF₃ (CeF₃-O) nanomaterial that exhibits photocatalytic activity under visible/NIR light for the first time. The homogeneous doping oxygen atoms were verified to efficiently modify the band structure of CeF₃. DFT calculation predicted the formation of an intermediate band within CeF₃ upon homogeneous doping of O at interstitial sites. The interaction between F and O atoms generates an intermediate band, which divides the total bandgap of CeF₃-O into two sub-bandgaps at about 1.7 eV and 2.9 eV, enabling CeF₃-O photocatalysis under visible light and NIR light. Reflectance spectra evidenced that the same bandgaps exist. The photocatalytic activities of CeF₃-O were tested by wavelength-controlled light. The rate constants of TC-HCl photodegrading under visible/NIR light are 12.85 × 10⁻³ min⁻¹ and 1.28 × 10⁻³ min⁻¹, respectively. The two-step electron transfer was also obviously confirmed in visible-light photocatalysis. In conclusion, the high oxygen doping builds a more applicable band structure of CeF₃-O for photocatalytic performance, charge transfer and special light response for visible/NIR light.