APCATA 469-2014-33

Synthesis of reverse micelle -FeOOH nanoparticles in ionic liquid asan only electrolyte: Inhibition of electron–hole pair recombination forefficient photoactivity

Discrete -FeOOH nanoparticles (5–10 nm) were synthesized by a simple electrochemical method usingan ionic liquid (IL), dodecyltrimethylammonium bromide (IL − FeOOH). IL that acts as an only electrolyte iscapable of producing IL − FeOOH nanoparticles without any agglomeration. Its crystallinity, morphology,functional characteristics, and surface area were analyzed using an X-ray diffractometer, a transmis-sion electron microscope, a Fourier-transform infrared spectrometer, and the Brunnauer–Emmett–Teller(BET) method, respectively. The characterization results verified that reverse micelle formation of IL playsan important role in the stabilization and miniaturization of the -FeOOH nanoparticles. The activity ofIL-FeOOH was tested on a photo-Fenton-like degradation of 2-chlorophenol (2-CP). Results showed thata nearly neutral condition of pH 5 was able to completely degrade 2-CP within 180 min of reaction at50◦C, using 0.03 g L−1of catalyst dosage and 50 mg L−1of 2-CP initial concentration, with only a smallamount of H2O2(0.156 mM). It was found that the reverse micelle formed around the catalyst surfacecould trap the photogenerated electron to inhibit the recombination of photo-induced electron–holepairs thus enhancing its catalytic activity. Kinetic studies using the Langmuir–Hinshelwood model illus-trated that a surface reaction was the controlling step of the process. A reusability study showed that thecatalyst was still stable after four subsequent reactions as shown by infrared spectroscopy. The resultsprovide strong evidence to support the potential use of using IL as an alternative electrolyte to synthesizephoto-Fenton-like nanocatalyst that can be used to treat organic pollutants such as 2-CP.