Hydrothermal Synthesis of Co₃O₄–Graphene for Heterogeneous Activation of Peroxymonosulfate for Decomposition of Phenol

Abstract

This paper reports the synthesis of Co 3 O 4 −reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for the decomposition of phenol. The surface morphologies and structures of the Co 3 O 4 −rGO hybrids were investigated by field emission scanning electron microscopy (SEM), energydispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Through an in situ chemical deposition and reduction, Co 3 O 4 −rGO hybrids with Co 3 O 4 nanoparticles at an average size of 33 nm were produced. Catalytic testing showed that 20 mg/L of phenol could be completely oxidized in 20 min at 25 °C on Co 3 O 4 −rGO hybrids, which is mostly attributed to the generation of sulfate radicals through Co 3 O 4 -mediated activation of PMS. Phenol oxidation was fitted by a pseudo-zero-order kinetic model. The rate constant was found to increase with increasing temperature and PMS dosage, but to decrease with increasing initial phenol concentration. The combination of Co 3 O 4 nanoparticles with graphene sheets leads to much higher catalytic activity than pure Co 3 O 4 . rGO plays an important role in Co 3 O 4 dispersion and decomposition of phenol.

Graphene Oxide/Co3O4 Nanocomposite: Synthesis, Characterization, and Its Adsorption Capacity for the Removal of Organic Dye Pollutants from Water

“…Graphene oxide (GO) was prepared by the oxidation of graphite powder under acidic conditions according to modified Hummers method using a mixture of H 2 SO 4 , NaNO 3 , and KMnO 4 . 35,36 For the synthesis of GO/Co 3 O 4 nanocomposite, 50 mg GO was dispersed into 20 mL deionized water by sonication for 1 h to achieve a uniform dispersion of GO. 100 mg as-prepared Co 3 O 4 nanoparticles were dispersed in deionized water for 15 min and were gradually added into GO suspension.…”

Synthesis of Magnetic Carbon Supported Manganese Catalysts for Phenol Oxidation by Activation of Peroxymonosulfate

“…Utilizing magnetic separation for catalysts recycle has attracted considerable research attention. Compared with traditional separation technologies such as centrifugation and filtration, magnetic separation through an external magnetic field is more convenient and less cost-intensive [16]. Magnetite (Fe 3 O 4 ) nanoparticles are prevalently employed as magnetic cores owing to their outstanding magnetic and electrochemical properties [17][18][19][20].…”

“…Magnetite (Fe 3 O 4 ) nanoparticles are prevalently employed as magnetic cores owing to their outstanding magnetic and electrochemical properties [17][18][19][20]. However, their high surface area to volume ratio and strong dipole-dipole attraction make them prone to aggregation, and the limited functional groups circumvent their further applications [16]. To circumvent such drawbacks, barrier materials have been investigated to prevent self-aggregation and to isolate from attached functional components [16,21].…”

“…However, their high surface area to volume ratio and strong dipole-dipole attraction make them prone to aggregation, and the limited functional groups circumvent their further applications [16]. To circumvent such drawbacks, barrier materials have been investigated to prevent self-aggregation and to isolate from attached functional components [16,21]. Recently, carbon coated magnetite nanospheres (Fe 3 O 4 /C) have been employed because of their low cytotoxicity and highly modifiable surface [22,23].…”

Preparation of TiO2/Silicalite-2@CoFe2O4 Magnetic Composites and Evaluation of their Photocatalytic Activity in Cr(VI) Removal

“…In this regard, Bai et al (2012) synthesized reduced graphene oxide-CoFe 2 O 4 hybrids by the one-pot ethanol-thermal method, and the as-obtained hybrids exhibited enhanced catalytic activity under visible light towards rhodamine B and methylene blue. Yao et al (2012) synthesized CoFe 2 O 4 graphene hybrids by simple chemical deposition followed by reduction of graphite oxide to graphene.…”