Construction of CoMoO4/g-C3N4 binary heterojunction photocatalyst with improving photocatalytic performance for ciprofloxacin under visible light

Nowadays, the threat of antibiotic residues in the natural water environment has aroused widespread concern. An environmentally and high-efficient way was needed urgently to alleviate the antibiotic contaminants. In this work, a Z-scheme CoMoO4/g-C3N4 (CoMO/CN) binary heterojunction photocatalyst was synthesized to eliminate ciprofloxacin (CPF) contaminant in the water environment. The crystal phase, element composition, morphology, light utilization capacity, and photoinduced carrier lifetime of the samples were investigated by XRD, FTIR, XPS, SEM, TEM, UV-Vis DRS, and PL. Benefiting from the construction of heterojunctions, the ob-tained 20CoMO/CN samples could remove 88 % of CPF (20 mg/L) under visible light within 3 h, which was 1.76 times and 2.09 times of CoMoO4 and g-C3N4, respectively. After five consecutive photocatalytic degradation processes, still 82 % of the CPF contaminants were degraded. Besides, the possible degradation mechanism of CPF over CoMO/CN photocatalyst was proposed, and the active species in the photocatalytic process was detected by quenching experiment. The results demonstrated that the formation of Z-structure heterojunction promoted the separation of photogenerated electrons and holes, improving the photocatalytic degradation ef-ficiency of CPF.

Automated summary

Nowadays, the concern over antibiotic residues in natural water environments has led to an urgent need for an environmentally friendly and highly efficient method to alleviate antibiotic contaminants. In this study, a Z-scheme CoMoO4/g-C3N4 binary heterojunction photocatalyst was synthesized to eliminate ciprofloxacin (CPF) contaminants in water. The obtained 20CoMO/CN samples showed a removal efficiency of 88% for CPF (20 mg/L) under visible light within 3 hours, which was 1.76 times and 2.09 times higher than that of CoMoO4 and g-C3N4, respectively. The formation of the Z-structure heterojunction promoted the separation of photogenerated electrons and holes, thereby improving the photocatalytic degradation efficiency of CPF.