Enhanced photocatalytic degradation of organic pollutants in actual sewage water with a full-spectrum-responsive NaYF4:Yb,Tm@NaYF4:Yb,Nd@TiO2@g-C3N4 nanoheterojunction photocatalyst

Full spectrum-excitation photocatalysis is promising for the environmentally friendly treatment of actual sewage with sunlight. High-efficiency, stable NaYF4:Yb,Tm@NaYF4:Yb,Nd@TiO2@g-C3N4 (UPTC) nanoheterojunction photocatalysts were fabricated via facile chemical synthesis. Nanophotocatalyst characterization revealed good crystallinity, strong composite formation, and a high separation rate of photoexcited charges. The synthesized UPTC was excited by ultraviolet, visible light and infrared light, exhibiting excellent full spectrum-response. Under near-infrared irradiation at 808 nm and 980 nm, UPTC effectively degraded rhodamine B (RhB). Under simulated sunlight, UPTC decomposed 88.6% malachite green, 92.2% rose bengal, and 90.8% RhB in 90 min. In photocatalysis, ·O2- played a dominant role. Moreover, the nanoheterojunction structure greatly improved photoexcited carrier separation. UPTC nanoheterojunction had excellent recycling capability. In actual sewage treatment, UPTC degraded 36.5% ammonia-nitrogen under simulated sunlight. In addition, UPTC exhibited sufficient biosafety. This study offers a fresh potential approach for producing highly efficient, stable, and biosafe nanoheterojunction photocatalysts for sewage treatment.