In this paper, the synthesis of LaFeO3 based on the gel combustion method has been improved by using citric acid (CA) as a secondary chelating agent on glucose. The synthesized samples were calcined at 600 degrees C and further characterized using X-ray diffraction (XRD), Fourier transform infrared, field-emission scanning electron microscopy (FESEM), scanning electron microscopy, energy-dispersive X-ray spectrophotometry, N-2 adsorption-desorption analyses, thermogravimetric analysis, and UV-vis-near-IR spectroscopy. The XRD data revealed that the pure orthorhombic perovskite phase LaFeO3 was obtained when CA was added on glucose. From FESEM and Brunauer-Emmett-Teller analysis, LaFeO3 synthesized using the addition of CA on glucose potentially showed well-uniform spherical particles and a high specific surface area of 40.77 m(2)/g with a particle size of 70 nm compared to glucose, which only showed 15.68 m(2)/g with a particle size of 100-300 nm. The photocatalytic activity of LaFeO3 was evaluated by the degradation of diazo dyes, Reactive Black 5 (RB5) under visible-light irradiation, indicating that synthesized LaFeO3 using the addition of CA on glucose exhibited excellent adsorption efficiency and remarkable photocatalytic activity with reaction rate constant K = 0.0680 min(-1), which was higher than that of the synthesized LaFeO3 based on glucose only with reaction rate constant K = 0.0087 min(-1).