Abstract: The development of efficient and stable photocatalysts for environmental remediation remains a key challenge in the treatment of emerging pollutants. In this work, heterostructured photocatalysts based on KNb3O8 and Ag3PO4 were successfully synthesized via a simple co-precipitation route and comprehensively characterized to evaluate their structural, optical, and photocatalytic properties. Structural characterizations confirmed the formation of well-defined crystalline phases and suggested interfacial lattice strain, indicative of strong interaction between the components. Among the prepared materials, the 50Nb3P composite, containing 50 wt% Ag3PO4, exhibited outstanding photocatalytic activity under visible light, achieving rapid degradation of Rhodamine B and high removal efficiencies for sulfamethoxazole (SMX) and ciprofloxacin (CIP), two antibiotics of environmental concern. Electronic analysis revealed enhanced visible-light absorption and suppressed electron-hole recombination, attributed to the heterojunction-driven charge separation. Scavenger tests confirmed that photogenerated holes were the dominant oxidative species, while electrons transferred to KNb3O8 promoted the generation of reactive oxygen species such as ⦁OOH and 1O2. Mineralization was verified by TOC and HPLC analyses, which showed decreased formation of persistent organic intermediates and improved conversion to CO2 and H2O. Although the catalyst showed performance loss over successive cycles due to photocorrosion, thermal treatment between uses effectively restored its activity. These findings demonstrate that the KNb3O8/ Ag3PO4 heterostructure not only reduces the required amount of silver-based material but also offers a robust, cost-effective platform for the visible-light-driven degradation of persistent organic contaminants.
Author(s): Nayara A Pinheiro, Marcelo Assis, Carlos HM Fernandes, Yeison N de la Rosa, Anelisse B Silva, Fernando A Buzzo, Caue Ribeiro, Marcos RV Lanza, Ary S Maia, Elson Longo
First published: 09/09/2025
