La-doped NaTaO3 nanoparticles: sol-gel synthesis and synergistic effect of CdO decoration toward efficient visible-light degradation of ciprofloxacin in water

Abstract The expanded use and disposal of antibiotics in water has led to health and environmental problems. However, photocatalysis is an efficient way to make progress toward the safe destruction of this emergent waste. Here, we present the photocatalytic degradation of ciprofloxacin (CP), an emerging antibiotic probe, over sol-gel synthesized La-doped NaTaO3 (LNTO) nanoparticles. We also studied the synergistic influence of adding a low amount (1.0‒4.0 wt. %) of CdO nanocrystals to the LNTO to enhance the photocatalytic performance under visible light. The introduction of CdO at only 3.0‒4.0 wt.% assisted the visible light response of the LNTO by reducing the bandgap energy (Eg) from 4.1 to approximately 2.6 eV and maintaining the high surface area of the mesostructured surface at 188 m2 g‒1. Additionally, the 3% CdO-loaded LNTO demonstrated complete photodegradation of CP within 90 min and a 732-fold increase in the degradation rate compared to that of pristine LNTO. The obtained CdO-modified LNTO could also be reused five times with negligible reduction in performance. The results reflect the significant contribution of CdO to the promotion of photoinduced charge separation. This study demonstrates the use of perovskite-based photocatalyst modification with simple oxides to promote sustainable visible-light degradation of such antibiotic waste in water.