One-step synthesis of magnetic-TiO2-nanocomposites with high iron oxide-composing ratio for photocatalysis of rhodamine 6G

In the study, a facile one-step method for synthesizing magnetic-TiO 2 -nanophotocatalysts was developed. With the same composing ratio of 0.5 and 0.35 (Fe:Ti, mole:mole), we prepared two types of magnetic-TiO 2 -nanocomposites as one-step synthesized Fe x O y -composed TiO 2 (Fe x O y /TiO 2 -0.5 and Fe x O y /TiO 2 -0.35) and two-step synthesized core-shell Fe x O y @TiO 2 (Fe x O y @TiO 2 -0.5 and Fe x O y @TiO 2 -0.35), and tested their performance in rhodamine 6G (R6G) photodegradation. X-ray diffraction (XRD) analysis showed that Fe x O y @TiO 2 -0.5 has the smallest crystallite size (16.8 nm), followed by Fe x O y @TiO 2 -0.5 (18.4 nm), Fe x O y /TiO 2 -0.35 (21.0 nm) and Fe x O y /TiO 2 -0.5 (19.0 nm), and X-ray photoelectron spectroscopy (XPS) suggested the decreasing percentage of Fe 3 O 4 from 52.1% to 36.7%-47.2% after Ti-deposition treatment. The saturated magnetisms followed the order: Fe x O y @TiO 2 -0.5 > Fe x O y @TiO 2 -0.35 > Fe x O y /TiO 2 -0.5 > Fe x O y /TiO 2 -0.35. R6G photodegradation followed the first order kinetics and was slightly influenced by pH but significantly affected by initial photocatalyst concentration. Fe x O y /TiO 2 -0.35 achieved the highest removal efficiency for R6G (92.5%), followed by Fe x O y @TiO 2 -0.35 (88.97%), Fe x O y @TiO 2 -0.5 (60.49%) and Fe x O y /TiO 2 -0.5 (48.06%). Additionally, all these magnetic-TiO 2 -nanocomposites had satisfied magnetic recoverability and exhibited laudable reusability after 5-times reuse, even achieving higher R6G removal efficiencies from 97.30% to 98.47%. Our one-step method took only 75 min for nanocomposite synthesis, 90 min less than conventional two-step method, showing its feasibility as a practical method for magnetic-TiO 2 -nanocomposite synthesis in industrial application.