Heterostructure of perovskite coupled graphitic carbon nitride for enhanced photodegradation under visible light

Abstract

This study aimed to prepare and characterize LaFeO₃ nanoparticles loaded graphitic carbon nitride (LFO/g-C₃N₄) photocatalyst and investigate the degradation of organic pollutants under UV and natural sunlight exposure. It is observed that LFO nanoparticles of an average size of about 67 nm were distributed on g-C₃N₄ sheets through chemical bonding owing to the formation of a composite. Compared to LFO and g-C₃N_4, composite has a good absorption ability to harvest more UV and visible light due to its large surface area and pore size. The photocatalytic studies revealed that the g-C₃N₄/LFO composite exhibits higher catalytic efficiency and stability for methylene blue (MB) degradation under UV and visible light. Under UV light irradiation, the degradation efficiency of LFO, g-C₃N_4, and g-C₃N₄/LFO composite in synthetic wastewater was found to be around 50, 80 and 93 % with corresponding rate constants 0.05, 0.02, and 0.1 min⁻¹ in 30 min, respectively. Under natural sunlight, the composite degraded 97 % of MB in 180 min with a rate constant of 0.016 min¹. The higher photocatalytic activity of the composite was attributed to the interfacial charge transfer between LaFeO₃ and g-C₃N_4, which are responsible for effective charge separation in the composite. Further, it has been investigated that singlet oxygen species (¹O₂) and hydroxyl radicals (^•OH) are the main reactive species that contributed considerably to the complete degradation of MB. The nanocomposite was also demonstrated to be a stable catalyst and can be reused without any further modification.