Controllable chemical synthesis of core-shell NaGdF4:Yb3+/Er3+@Bi4O5I2/Bi5O7I Z-scheme heterojunction for efficient tetracycline hydrochloride photodegradation

Constructing heterojunction photocatalysts that can make additional utilization of near-infrared (NIR) light has been a global scientific problem and has gained widespread research interest. Upconversion nanoparticles (UCNPs) collaborate with semiconductors to construct UCNPs-based photocatalysts that are used to improve solar energy utilization. In this work, the as-prepared UCNPs-based photocatalysts consisting of NaGdF 4 :Yb 3+ /Er 3+ (NGFYE) and bismuth oxyiodide (BOI) are synthesized by chemical epitaxial growth method and in-situ calcination process. The crystalline phase , morphology, optical and electrochemical properties of NGFYE@BOI samples are investigated in detail. Besides, Bi 4 O 5 I 2 /Bi 5 O 7 I Z-type heterojunction is confirmed by EPR test. Moreover, the photocatalytic elimination of tetracycline hydrochloride (TCH) and its photocatalytic mechanism by NGFYE@BOI samples are explored. This work may provide a promising idea for the efficient and controlled synthesis of UCNPs-based photocatalysts, which will contribute to the future utilization of solar energy.