Synergistic photothermal conversion and visible-light photodegradation of antibiotic in S-type TiO2 derived Ti3C2-MXene loaded on NaYF4: Tm3+, Er3+, Yb3+ @BiOI

Abstract

Here, the collaboration of photocatalysis and photothermal conversion has been defined as an efficient strategy for converting unusable near-infrared (NIR) light to operational ultraviolet–visible (UV–vis) photons. For this, a new heterostructured photocatalyst NaYF₄: Tm³⁺, Er³⁺, Yb³⁺ @ BiOI was successfully synthesized using a simple hydrothermal approach paired with electrostatic self-assembly. The results show that BiOI can indirectly use the NIR portion to produce electron-hole pairs due to the presence of upconversion nanoparticles (UCNPs). On the other hand, loading TiO₂ derived Ti₃C₂ MXenes on NaYF₄: Tm³⁺, Er³⁺, Yb³⁺ @ BiOI increased tetracycline (TC) degradation to 36% and 90%, compared to narrow band gap BiOI, within 120 min under NIR light irradiation and sunlight irradiation, respectively. Moreover, the reaction rate of UCNP@BiOI@TiO₂–Ti₃C₂ was found to be 2.85 times higher under sunlight compared to NIR. It can be attributed to the synergistic photocatalytic and photothermal effects triggered by NIR light. In addition, the broad photoresponse range of TiO₂ and the Schottky junction formed by Ti₃C₂ MXenes between TiO₂ and BiOI facilitate charge separation while reducing photo-generated electron-hole pair recombination. The reduced recombination rate in the synthesized heterojunction was further substantiated by the larger photocurrent response and smaller EIS arc. Excellent catalytic activity is explained by the S-scheme mechanism, which produces holes at the valence band and superoxide radicals at the conductive band in the BiOI and Ti₃C₂, respectively. Significantly, the cycling results demonstrated that the photocatalysts had the requisite reusability and recyclability for real-world applications. The cooperative MXene and UCNPs utilized in this study provide a helpful basis for the logical design of full-spectrum photocatalysts.