Cobalt-doped LaFeO₃ for photo-Fenton degradation of organic pollutants and visible-light-assisted water splitting

The increasing demand for clean energy sources and the growing concerns about environmental pollution have led to a significant interest in developing efficient photocatalytic and photoelectrochemical systems. Here, we report the visible-light-induced photo-Fenton catalytic degradation of Methylene Blue (MB) dye over LaFeO₃ and LaCo_xFe_1−xO₃ (x = 0.01, 0.05, 0.1) catalysts synthesized via the facile combustion method. The LaCo_0.01Fe_0.99O₃ has significantly enhanced the photo-Fenton catalytic efficiency of LaFeO₃ from 67.75 to 93.85% for MB dye removal after 180 min of light irradiation. The rate constants calculated via the pseudo-first-order kinetics mechanism are found to be 0.00532/min for LaFeO₃ and 0.01476/min for LaCo_0.01Fe_0.99O₃, respectively. In addition, the most effective LaCo_0.01Fe_0.99O₃ catalyst has demonstrated remarkable degradation performance towards Tetracycline (TC) and Methyl Orange (MO) dye with an efficacy of 93.81% and 69.67%, respectively, indicating its versatility. Further, the pristine and doped LaFeO₃ were structurally optimized using DFT, and the computed band gaps were following the experimental data. Interestingly, the same catalyst can be employed as a light-induced electrocatalyst in addition to water treatment by taking advantage of its dual functionality. The LaCo_0.01Fe_0.99O₃ catalyst achieved a benchmark current density of 10 mA/cm² for H₂ evolution at an overpotential of 297 mV vs. RHE which further improved to 190 mV vs. RHE under illumination. This work provides valuable insights on partial Co incorporation at the B-site of LaFeO₃ for the development of visible-light-induced photocatalytic and electrocatalytic systems, which is hoped to contribute to the advancement of sustainable energy production and environmental remediation.