Solar radiation assisted Photocatalytic Degradation of Congo red using Ce doped LaCoO\(_{3}\)

A viable sol-gel synthesis technique was used to synthesize LaCoO3​ and Ce doped LaCoO3 for degradation of congo red dye taking a renewable source of light i.e solar radiation. The crystalline structure, morphology, and optical properties of the synthesized catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) analysis of Ce-doped LaCoO₃ confirmed the presence of La (3d), Ce (3d), Co (2p), C (1s), and O (1s) and their valence states in the perovskite matrix, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and ultraviolet diffuse reflectance spectroscopy (UV-DRS). The XRD analysis with a prominent diffraction peak detected at a 2θ value of 32.88⁰ indicated a well-defined crystalline structure, The calculated average crystallite size of LaCoO3 and Ce doped LaCoO3 is 10.59 and 9.30 nm repectively. The Ce doped LaCoO3 was observed to cause a structural phase transition from a rhombohedral to a cubic phase, while maintaining the lattice geometry, while maintaining the lattice geometry. The photodegradation of congo red dye using prepared catalysts was studied by changing pH, initial dye concentration, catalyst dose and time. The photocatalytic performance of Ce doped LaCoO3 showed greater efficiency than neat LaCoO3​ towards degradation of congo red dye under solar light exposure. The optimum degradation of congo red dye was nearly 85% compared to nearly 77% for Ce doped LaCoO3 and LaCoO3​ respectively for initial dye concentration of 25 ppm and a catalyst dose of 60 mg in 135 min. The kinetics followed a pseudo-1st order kinetics and the mechanistic study indicated the active involvement of hydroxide (OH.) and super oxide (.O2-) radicals during of the degradation congo red dye by Ce doped LaCoO3 catalyst. The SEM analysis demonstrates a well-crystallized sample with a uniform particle distribution, though it exhibits some degree of agglomeration.