Electrochemical post-treatment of bimetallic-ICP/RGO precursor for Z-scheme CuO_x·Ag₂O/RGO hetero-structure with catalytic activity enhancement for visible-light-driven photo-Fenton degradation of tetracycline

In this work, rationally designed bimetallic infinite coordination polymer (ICP) was mixed with reduced graphene oxide (RGO) to serve as precursors for the preparation of CuO_x·Ag₂O/RGO hetero-structure. As the growth of metal oxide nuclei within the ICP network was restricted and more surface-oxygenated species of RGO were exposed during the electrochemical post-treatment process, the CuO_x·Ag₂O NPs supported on RGO were evenly-distributed nanoparticles with ultra-small size (2.89 ± 0.37 nm), which exhibited excellent catalytic activity enhancement in visible-light-driven photo-Fenton degradation of the model antibiotic tetracycline (TC). Moreover, since the CuO_x·Ag₂O/RGO was in-situ decorated on ITO glass, recycling of the catalysts with long-term stability could be realized, even after 5 cycles, 91.4 % of TC (10 mL, 50 mg/L) could be degraded within 60 min. A series of characterization and experiment results demonstrated the improved catalytic performance of CuO_x·Ag₂O/RGO for photo-Fenton degradation was stemmed from the synergistic effect of the components within the catalyst, which facilitated solar energy absorption, accelerated the separation of photo-generated hole-electron pairs through Z-scheme charge transfer way, and strengthened their mechanical stability on the substrate. This newly created catalysts for photo-Fenton reaction are of great potential to achieve the practical treatment of antibiotics-contaminated wastewater.