Efficient activation of peroxymonosulfate-based Fenton-like system using CuCo₂O₄/g-C₃N₄ prepared by Cu⁺-Co²⁺ self-doped: g-C₃N₄ driven reduction-oxidation cycling mechanism of Cu and Co metals

A large specific surface area Cu⁺-Co²⁺ self-doped CuCo₂O₄/g-C₃N₄ composite was synthesized in situ by a simple hydrothermal combined calcination method. This material is a kind of highly active catalyst suitable for peroxymonosulfate (PMS)-based Fenton-like system, with strong resistance to impurity ions interference, universality to pollutants, and good recyclability. Through XRD (X-ray diffraction), FTIR (Fourier transform infrared spectrometer), XPS (X-ray photoelectron spectrum), TEM (transmission electron microscopy) and catalytic experiments, it can be seen that CuCo₂O₄ nanoparticles with diameter of 6–9 nm are uniformly distributed on the surface of g-C₃N₄ to form CuCo₂O₄/g-C₃N₄. At room temperature, PMS-based Fenton-like system catalyzed by CuCo₂O₄/g-C₃N₄ could degraded tetracycline (TC) to 85.8% in 8 min. The mechanism of CuCo₂O₄/g-C₃N₄ activating PMS was discussed in detail. The results show that the surface electron transfer ability of C in g-C₃N₄ can promote the efficient reduction-oxidation (REDOX) cycle of Cu⁺/Cu²⁺ and Co²⁺/Co³⁺ on the catalyst surface, thus provide a continuous impetus for the activation of PMS.