Coupling effects between metal–organic framework derivatives and oxygen-deficient TiO2 nanotubes: identified charge-transfer processes and photoelectric synergistic effect

Abstract

The in situ self-assembling of metal–organic frameworks (MOFs) to construct thin-film electrodes is a major challenge in designing efficient photoelectric catalysts. In this study, we propose a method for preparing MOF derivative and TiO₂ nanotube (TNT) coupled catalysts with S-scheme Ar–ZrO₂/Ti₂O₃-TNTs, where Ar–ZrO₂ derived from NH₂-UiO-66 was modified in situ inside Ti₂O₃-TNTs. The TiO₂ nanotubes not only played an important role in substrate loading and support but also served as the source of Ti³⁺ for the self-modifying. Such a photoelectrocatalysis (PEC) system exhibited more than 95% degradation for the treatment of tetracycline wastewater with excellent photoelectric synergy by visible light (λ > 420 nm) and auxiliary circuitry owing to its excellent electrical conductivity, S-type heterogeneous structure, better photogenerated e⁻/h⁺ separation, and fast photocarrier transfer. Even in complicated water conditions, the photoelectrode generated ¹O₂, ˙O₂⁻, and h⁺ were shown to be the most significant active species for directly promoting the PEC oxidation of tetracycline. This research enriches the knowledge on the development and modification of materials using MOF derivatives to generate photoelectric anodes for treating antibiotics wastewater.