Hollow multi-dimension CoCeS/C as peroxymonosulfate activator toward ofloxacin degradation via coexisting free radical and nonradical pathways

A catalyst with multi-metal introduction and a hollow structure is very promising for peroxymonosulfate (PMS) activation. In this study, Ce doped hollow bimetallic sulfide carbon composite (CoCeS/C) were fabricated from three dimensional layered double hydroxides (LDHs), which was synthesized via metal-organic frameworks (MOFs) self-sacrificial template strategy. The as-synthesised composite was applied to the catalytic degradation of ofloxacin (OFX) and the result indicated that the reaction rate constant (k2) of Ce doped CoCeS/C (18.539 mmol−1·L·min−1) was about 5.7 times higher than CoS/C (3.230 mmol−1·L·min−1) which was without Ce doping. Singlet oxygen (1O2) and SO4-• were verified as the dominant reactive oxygen species (ROS) responsible for OFX via quenching tests and electron paramagnetic resonance spectroscope (EPR). The catalyst kept high removal efficiency over the pH range of 3.0–11.0. In addition, the catalyst still showed good reusability after four runs, as well as strong resistance to versatile inorganic ions and background organic matters in the oxidative treatment of OFX. Finally, degradation pathways were proposed by analyzing the degradation intermediates. These results revealed that the designed CoCeS/C catalyst exhibits wide promising application prospects for the degradation of organic residues in environmental remediation.