Impacts of annealing temperature on morphological, optical and photocatalytic properties of gel-combustion-derived LaFeO3 nanoparticles

Abstract

In this study, LaFeO3 photocatalyst had been synthesized via a gel combustion method using glucose and citric acid as dual chelating agents. Furthermore, the effect of different calcination temperatures (400 °C, 500 °C and 600 °C) on the physicochemical properties of the synthesized LaFeO3 were also investigated. From the study, LaFeO3 nanoparticles calcined at 400 °C were selected as the most promising photocatalyst due to their amorphous nature which benefits from the presence of a surface defect. In addition, the amorphous LaFeO3 also recorded the highest surface area with a value of 70.02 m2/g which contributed to the enhancement of photocatalytic activity for the degradation of humic acid (HA). Besides that, effect of operational parameters such as photocatalyst loading (0.6–1.20 g/L), initial concentration of HA (10–40 mg/L) and aeration (presence of oxygen) for HA degradation under visible light irradiation was studied using the amorphous LaFeO3. Overall, the optimal values for degradation of HA were observed at a catalyst loading of 1.0 g/L and initial concentration of 10 mg/L. In a nutshell, the perovskite-based photocatalyst was successfully synthesized where the amorphous LaFeO3 outperformed the crystalline LaFeO3 as regards higher reaction rate constant 0.0305 min−1 (amorphous; 400 °C) compared to 0.0250 min−1 (crystalline; 500 °C) and 0.01329 min−1(crystalline; 600 °C), respectively.