Abstract:Hematite (α-Fe2O3)/graphitic carbon nitride (g-C3N4) nanofilm catalysts were synthesized on fluorine-doped tin oxide glass by hydrothermal and chemical vapor deposition. Scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses of the synthesized catalyst showed that the nanoparticles of g-C3N4 were successfully deposited on α-Fe2O3 nanofilm. The methylene blue degradation efficiency of the α-Fe2O3/g-C3N4 composite catalyst was 2.6 times grea… Show more
“…MO degradation was significantly suppressed when BQ was utilized as a scavenger. Thus, the results of the trapping experiments clearly demonstrate that the hydroxyl radical (•OH) and hole (h + ) play a minor role in the photocatalytic removal of MO, whereas, O2 •− is the primary ROS that further degrades the MO over the g-C3N4/α-Fe2O3 nanocomposite, which is in good agreement with recent studies [44][45][46][47].…”
Section: Photocatalytic Mo Degradation Mechanismsupporting
This study describes the preparation of graphitic carbon nitride (g-C3N4), hematite (α-Fe2O3), and their g-C3N4/α-Fe2O3 heterostructure for the photocatalytic removal of methyl orange (MO) under visible light illumination. The facile hydrothermal approach was utilized for the preparation of the nanomaterials. Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) were carried out to study the physiochemical and optoelectronic properties of all the synthesized photocatalysts. Based on the X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance (DRS) results, an energy level diagram vs. SHE was established. The acquired results indicated that the nanocomposite exhibited a type-II heterojunction and degraded the MO dye by 97%. The degradation ability of the nanocomposite was higher than that of pristine g-C3N4 (41%) and α-Fe2O3 (30%) photocatalysts under 300 min of light irradiation. The formation of a type-II heterostructure with desirable band alignment and band edge positions for efficient interfacial charge carrier separation along with a larger specific surface area was collectively responsible for the higher photocatalytic efficiency of the g-C3N4/α-Fe2O3 nanocomposite. The mechanism of the nanocomposite was also studied through results obtained from UV-vis and XPS analyses. A reactive species trapping experiment confirmed the involvement of the superoxide radical anion (O2•−) as the key reactive oxygen species for MO removal. The degradation kinetics were also monitored, and the reaction was observed to be pseudo-first order. Moreover, the sustainability of the photocatalyst was also investigated.
“…MO degradation was significantly suppressed when BQ was utilized as a scavenger. Thus, the results of the trapping experiments clearly demonstrate that the hydroxyl radical (•OH) and hole (h + ) play a minor role in the photocatalytic removal of MO, whereas, O2 •− is the primary ROS that further degrades the MO over the g-C3N4/α-Fe2O3 nanocomposite, which is in good agreement with recent studies [44][45][46][47].…”
Section: Photocatalytic Mo Degradation Mechanismsupporting
This study describes the preparation of graphitic carbon nitride (g-C3N4), hematite (α-Fe2O3), and their g-C3N4/α-Fe2O3 heterostructure for the photocatalytic removal of methyl orange (MO) under visible light illumination. The facile hydrothermal approach was utilized for the preparation of the nanomaterials. Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET) were carried out to study the physiochemical and optoelectronic properties of all the synthesized photocatalysts. Based on the X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance (DRS) results, an energy level diagram vs. SHE was established. The acquired results indicated that the nanocomposite exhibited a type-II heterojunction and degraded the MO dye by 97%. The degradation ability of the nanocomposite was higher than that of pristine g-C3N4 (41%) and α-Fe2O3 (30%) photocatalysts under 300 min of light irradiation. The formation of a type-II heterostructure with desirable band alignment and band edge positions for efficient interfacial charge carrier separation along with a larger specific surface area was collectively responsible for the higher photocatalytic efficiency of the g-C3N4/α-Fe2O3 nanocomposite. The mechanism of the nanocomposite was also studied through results obtained from UV-vis and XPS analyses. A reactive species trapping experiment confirmed the involvement of the superoxide radical anion (O2•−) as the key reactive oxygen species for MO removal. The degradation kinetics were also monitored, and the reaction was observed to be pseudo-first order. Moreover, the sustainability of the photocatalyst was also investigated.
“…[ 30,31 ] It also catalyzes Fenton and photo‐Fenton reactions with UV‐light irradiation and H 2 O 2 , producing more ROS to attack pollutants in water. [ 32 ] These characteristics make it an appealing material for the fabrication of visible light‐powered micro/nanorobots for water remediation. However, hematite photocatalytic applications are limited by its high electron–hole recombination rate and low electron mobility.…”
The increasing use of polymers has led to an uncontrollable accumulation of polymer waste in the environment, evidencing the urgent need for effective and definitive strategies to degrade them. Here, self‐propelled light‐powered magnetic field‐navigable hematite/metal Janus microrobots that can actively move, capture, and degrade polymers are presented. Janus microrobots are fabricated by asymmetrically depositing different metals on hematite microspheres prepared by low‐cost and large‐scale chemical synthesis. All microrobots exhibit fuel‐free motion capability, with light‐controlled on/off switching of motion and magnetic field‐controlled directionality. Higher speeds are observed for bimetallic coatings with respect to single metals. This is due to their larger mixed potential difference with hematite as indicated by Tafel measurements. As a model for polymers, the total degradation of high molecular weight polyethylene glycol is demonstrated by matrix‐assisted laser desorption/ionization mass spectrometry. This result is attributed to the active motion of microrobots, enhanced electrostatic capture of polymer chains, improved charge separation at the hematite/metal interface, and catalyzed photo‐Fenton reaction. This work opens the route toward the degradation of polymers and plastics in water using light.
“…The results revealed that all prepared iron oxides with and without surfactants were formed in spherical α-Fe 2 O 3 with a diameter range of 15-205 nm based on the surfactant sort and concentration. As well many hematite composites were fabricated using a hydrothermal route, such as activated carbon/α-Fe 2 O 3 (Ermanda et al 2021), Co-doped α-α-Fe 2 O 3 (Cai et al 2021), α-Fe 2 O 3 /g-C 3 N 4 (Lee and Park 2020), and chitosan-coated-α-Fe 2 O 3 (Badry et al 2021).…”
The rapid urbanization and industrialization is causing worldwide water pollution, calling for advanced cleaning methods. For instance, pollutant adsorption on magnetic oxides is efficient and very practical due to the easy separation from solutions by an magnetic field. Here we review the synthesis and performance of magnetic oxides such as iron oxides, spinel ferrites, and perovskite oxides for water remediation. We present structural, optical, and magnetic properties. Magnetic oxides are also promising photocatalysts for the degradation of organic pollutants. Antimicrobial activities and adsorption of heavy metals and radionucleides are also discussed.
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