Ruisheng Hu

A novel efficient boron-doped LaFeO3 photocatalyst with large specific surface area for phenol degradation under simulated sunlight

Boron-doped LaFeO3 photocatalysts were successfully synthesized by a facile sol–gel method using glucose as a novel complexing agent. The photocatalysts were characterized by XRD, SEM, TEM, UV-vis DRS, BET, XPS and O2-TPD techniques. The results show that the catalysts formed pure orthorhombic perovskite structures when the boron-doped content was less than 7.5%. The specific surface area of 3.5% B-doped catalysts reached 62.3 m2 g−1, but pure LaFeO3 achieved just 6.4 m2 g−1. The content of absorbed oxygen increased to 61.28% for 3.5% B-doped LaFeO3 from 38.2% for undoped LaFeO3. Compared with undoped and other boron-doped LaFeO3 photocatalysts, the 3.5% B-doped LaFeO3 catalyst exhibits the best photocatalytic activity for phenol degradation after 300 min of simulated sunlight irradiation. The superior photocatalytic activity of B-doped LaFeO3 is ascribed to these factors: first, the large specific surface area; second, the efficient separation of photogenerated electrons and holes on the surface of the catalyst; third, the increase in oxygen centers for photocatalytic activity.

Influence of lanthanum-doping on photocatalytic properties of BiFeO 3 for phenol degradation

A series of BiFeO 3 and lanthanum-doped BiFeO 3 photocatalysts were synthesized by a facile sol-gel method using citric acid as complexing agent, and used to remove phenol in industrial wastewater under simulated sunlight irradiation. The samples were characterized by X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The introduction of La effectively suppressed the generation of an impurity phase. All the metals (La, Bi and Fe) are well distributed. Under simulated sunlight irradiation, the La-doped BiFeO 3 photocatalysts exhibited superior photocatalytic activity to pure BiFeO 3 . The 15% La-doped BiFeO 3 photocatalyst exhibited the best activity, with a degradation rate of 96% and COD removal rate of 81.53% after irradiation for 180 min, and it showed good recycling stability. The enhanced photocatalytic ability of 15% La-doped BiFeO 3 was attributed to the increase of adsorbed surface hydroxyl groups, enhancement of visible light absorption and reduction of electron-hole recombination. We confirmed that the primary active species was · OH by adding different scavengers during the photodegradation of phenol and proposed a reaction mechanism based on these experiments.