Optimizing 3d electronic structure of LaCoO3 based on spin state tuning for enhancing photo-Fenton activity on tetracycline degradation

The water pollution caused by the abuse of antibiotics has significant harmful effects on the environment and human health. The photo-Fenton process is currently the most effective method for removing antibiotics from water, but it encounters challenges such as inadequate response to visible light, low yield and utilization of photogenerated electrons, and slow electron transport. In this study, spin state regulation was introduced into the photo-Fenton process, and the spin state of Co³⁺ was regulated through Ce displacement doping. The intermediate-spin state Ce-LaCoO₃ could degrade 91.6 % of tetracycline within 120 min in the photo-Fenton system, which is 15.2 % higher than that of low-spin state LaCoO₃. The improved degradation effect is attributed to the reasons that Ce-LaCoO₃ in the intermediate-spin state have lower band gap, better charge transfer ability, and stronger adsorption capacity of H₂O₂, which can accelerate the redox cycle of Co²⁺/Co³⁺ and promote the generation of ·OH. This study presents a unique strategy for synthesizing efficient photo-Fenton materials to treat antibiotic wastewater effectively.