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.