Microwave-hydrothermal synthesis of F and Fe co-doped CeO2 photocatalysts for efficient removal of 2,4,6-TCP under visible light

In recent years, the massive use and migration of chlorine-containing organics into the environment potentially threaten the natural environment and human health. Advanced oxidation technology based on photocatalysts is a promising approach for the degradation of chlorine-containing organic pollutants, but the development of stable and efficient photocatalysts remains a challenge. In this study, a new visible light-responsive photocatalyst based on F and Fe co-doped CeO2 (FeFC) was synthesized by making full use of overall heating characteristic of microwaves. XRD, SEM-EDS, XPS, BET and DRS results showed that F and Fe was successfully co-doped into CeO2 with increased BET surface and narrowed band gap. The degradation experiments showed that the co-doping of F and Fe significantly enhanced the photocatalytic activity of CeO2 by enhancing visible light absorption and charge carriers separation. Moreover, CeO2 material with both F and Fe doping of 10 % (FeFC-10) showed the highest removal (99.8%) and de-chlorination (89%) rates of 2,4,6-TCP within 4h, which was 3.8 and 3.2 times higher than that of pure CeO2 prepared by microwave and muffle furnace, respectively. Free radical scavenging experiments and electron paramagnetic resonance (EPR) tests finally demonstrated that the h+ and ·OH were the active species that played a catalytic redox role in this reaction system. Furthermore, the degradation intermediates of 2,4,6-TCP were identified by LC-MS and the possible reaction pathways were suggested. In this paper, the photocatalyst (FeFC-10) synthesized by microwave-hydrothermal method could not only save time and energy, but also efficiently degrade 2,4,6-TCP, which could provide the theory and practice for protecting water environment contaminated by chlorine-containing organics through the synthesis of CeO2 based photocatalysts.