Fe3O4/SiO2/C nanocomposite as a high-performance Fenton-like catalyst in a neutral environment

Abstract

The traditional Fenton system (Fe²⁺–H₂O₂) only works in an acidic environment and produces a large quantity of sludge. In this study, we reported that a Fe₃O₄/SiO₂/C nanocomposite (FSCNC) could be used as a high-performance Fenton-like catalyst for the decoloration of methylene blue (MB). To prepare FSCNC, SiO₂ was precipitated on Fe₃O₄ cores by the hydrolysis of tetraethyl orthosilicate, and the deposition of carbon was via the hydrothermal dehydrogenation of glucose. FSCNC showed much higher catalytic activity than naked Fe₃O₄ at a neutral pH of 7.5. Efficient decoloration of MB was achieved within 15 min in the FSCNC–H₂O₂ system. The FSCNC–H₂O₂ system worked well in the pH range of 3.5–9.5 and showed good resistance to radical scavengers tertiary butanol and ethanol. Higher H₂O₂ concentration and temperature were preferred to achieve faster kinetics. The regeneration of FSCNC was easily achieved by washing the catalyst and about 70% of the initial activity was retained after 8 cycles. The implication to the future applications of FSCNC as a Fenton-like catalyst is discussed.