Abstract
The sol-gel technique was employed to synthesize La₂NiO₄, La₂CuO₄, La₂NiO₄/g-C₃N₄, and La₂CuO₄/g-C₃N₄ nanoparticles. The structural characteristics and surface morphology of the as-prepared nanoparticles were assessed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Fourier-transform infrared (FT-IR) analysis verified the existence of metal‑oxygen (M–O) bonds. The bandgap energy was determined via Tauc plots derived from UV–Vis spectroscopy. The synthesized materials were tested as photocatalysts for the degradation of methylene blue dye across a range of medium pH values (2–12). A comparison of the photocatalytic performance between La₂NiO₄/g-C₃N₄ and La₂CuO₄/g-C₃N₄ revealed the highest activity under basic conditions. This enhanced photocatalytic efficiency is attributed to effective charge transfer between the valence band (VB) and conduction band (CB) in the presence of g-C₃N₄, which promotes the generation of reactive species (•OH and •O₂⁻) responsible for methylene blue degradation. Therefore, it is concluded that the fabricated nanoparticles hold potential for removing toxic pollutants from industrial wastewater.