Highly efficient activation of molecular oxygen by Cu@N doped carbon for antibiotic degradation

Nanoparticle aggregation and metal ion leaching contribute to the poor cycling stability of nanostructured zero valent copper (ZVC) catalyst for molecular oxygen activation, greatly hindering its industrial application in wastewater treatment. Herein, N doped carbon coated Cu 0 (Cu@CN) catalysts were prepared by using polyvinylpyrrolidone (PVP) modified Cu-MOF as precursor through high-temperature pyrolysis method. The phase structure, surface morphology and microstructure information of as-synthesized catalyst were systematically characterized by XRD, Raman, SEM, XPS and TEM. Norfloxacin (NOR) degradation in Cu@CN/air system showed Cu@CN3-600, prepared by using 0.3 g PVP as N source and pyrolysis temperature of 600 ℃, exhibited excellent catalytic activity and stability as well as universality in treating various organic wastewaters. The removal rate of NOR after 60 min was 96.05 % and meantime total organic carbon (TOC) decreased by 49.80 % under pH 4.0 and 1.2 g/L catalyst. After three cycles, it still maintained 81.53 % removal rate, owing to the protection effect of N doped carbon on active Cu component against its leaching during degradation. The reaction mechanism of Cu@CN3-600 activating O 2 for NOR degradation was deciphered by reactive oxygen species scavenging experiment, electron paramagnetic resonance (EPR) and density functional theory (DFT) calculation. Finally, four possible degradation pathways were proposed by identifying 16 intermediates through liquid chromatography-mass spectrometry (LC-MS) technology. This work can provide a guidance for designing highly efficient Cu-based molecular oxygen activation catalyst for wastewater abatement.