Photoinduced charge property of nanosized perovskite-type LaFeO3 and its relationships with photocatalytic activity under visible irradiation

Abstract In this paper, ABO 3 -type perovskite LaFeO 3 nanosized photocatalysts were synthesized by a sol–gel method, using citric acid (HOOCCH 2 C(OH)(COOH)CH 2 COOH) as complexing reagent and La(NO 3 ) 3 ·6H 2 O and Fe (NO 3 ) 3 ·9H 2 O as raw materials. The as-prepared samples also were characterized by several testing techniques, such as thermogravimetry–differential thermal analysis (TG-DTA), X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET), infrared spectrum (IR), ultraviolet–visible diffuse reflection spectrum (UV–vis DRS), photoluminescence spectrum (PL), surface photovoltage spectroscopy (SPS) and electrical field induced surface photovoltage spectroscopy (EFISPS). The sample activity of different LaFeO 3 nanoparticles for degrading Rhodamine B solution under visible irradiation ( λ > 400 nm) was evaluated. The effects of thermal treatment temperature on photoinduced charge property and photocatalytic activity were mainly investigated, together with their relationships. The results show that the LaFeO 3 sample calcined at 500 °C exhibits higher activity, and the activity decreases with increasing calcination temperature, which is in good agreement with the characterization results. The weaker is the PL and SPS signal, the higher is the photocatalytic activity. Moreover, the activity of all as-prepared LaFeO 3 samples is higher than that of international P-25 TiO 2 under visible irradiation.