Efficient generation of singlet oxygen (1O2) by hollow amorphous Co/C composites for selective degradation of oxytetracycline via Fenton-like process

Abstract

• Hollow amorphous Co/C composites were prepared via one-step solvothermal method. • Co/C-3 + H 2 O 2 system achieved great OTC degradation under complicated water matrices. • 1 O 2 converted from ·O 2 – was the dominated ROS in this Fenton-like process. • The electron cycle of ≡Co 2+/3+ -O-C/H played a vital effect on the generation of 1 O 2. Singlet oxygen ( 1 O 2 ) is an electrophilic species that has great selectivity for breaking down electron-rich refractory organic pollutants. However, in most cases, 1 O 2 plays a minor role in the Fenton-like process due to its low yield, the contributions of which are usually covered by free radicals. Here, we provide the first report on a type of hollow amorphous Co/C composites prepared for the efficient generation of 1 O 2 to degrade oxytetracycline (OTC) selectively in the Fenton-like system. The optimized Co/C samples (Co/C-3) obtained the best degradation performance of OTC near to 100% under neutral conditions, along with satisfactory reusability and stability. Additionally, it exhibited a high anti-interference capacity for inorganic anions and natural organic matter s in the different water qualities. XPS spectrum revealed that the electron cycle of ≡Co 2+ -O-C/H and ≡Co 3+ -O-C/H played a vital effect on the formation of 1 O 2 . Quenching experiments and EPR testing further verified that 1 O 2 converted from ·O 2 – was the dominant oxidative species, and no hydroxyl radical (·OH) appeared in this reaction. Moreover, the results of the Fukui function and T.E.S.T (Toxicity Estimation Software Tool) analysis provided significant assistance in the exploration of degradation pathways and ecological risks of OTC and its intermediates.