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Photochemical deposition of silver on Fe2O3 nanotubes prepared by anodization and exploring their photoelectrochemical activity
摘要： Novel silver-decorated Fe2O3 nanotubes (Ag/FeNT) have been synthesized by a simple, fast and efficient method. Fe2O3 nanotubes (FeNT) have been successfully synthesized on pure iron plates by electrochemical anodizing, followed by silver deposition on the surface of the nanotubes through photodeposition. Various instrumental techniques have been used to investigate the morphology, structure and optical properties of the prepared samples. In addition, the photoelectrochemical water splitting performance of the new electrodes has been studied. An increased photocurrent density and a greatly enhanced onset potential for photoelectrochemical activity have been shown by Ag/FeNT electrodes in comparison with bare FeNT. Silver-decorated Fe2O3 nanotube (sample Ag/FeNT1) shows an almost 2.5-fold increase in photocurrent compared with bare Fe2O3 nanotube. Efficient charge carrier separation, visible light sensitization due to Ag nanoparticles on Fe2O3 nanotube and enhanced electrical conductivity are responsible for the increase in the photoelectrochemical water splitting activity of Ag/FeNT.
关键词： Water splitting,Silver deposition,Fe2O3 nanotubes,Photoelectrochemical activity
更新于2025-09-09 09:28:46
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Redox-Mediated Shape-transformation of Fe3O4 Nanoflake to Chemically Stable Au-Fe2O3 Composite Nanorod for High-Performance Asymmetric Solid-State Supercapacitor Device
摘要： Development of a stable and highly active metal oxide based electrochemical supercapacitor is a major challenge. Herein, we report Au-Fe2O3 nanocomposite having tiny amount of gold (3 atomic % Au) by employing a simple redox-mediated synthetic methodology using modified hydrothermal system. Structural and morphological studies of the synthesized Au-Fe2O3 nanocomposite have been performed both experimentally (XRD, IR, Raman, XPS, TEM and FESEM analyses) and theoretically (WIEN2K). A probable dissolution-nucleation-recrystallization growth mechanism has been suggested to explain the morphological transformation from Fe3O4 nanoflake to Au-Fe2O3nanorod. We have observed the superior chemical stability of Au-Fe2O3 nanocomposite in acidic medium due to composite formation. The electrochemical measurement of the synthesized Au-Fe2O3 nanocomposite exhibits specific capacitance of ~570 F g-1 at the current density of 1 A g-1 in 0.5 M H2SO4 electrolyte. The result is superior compared to the mother component i.e., Fe2O3 (138 F g-1) under identical condition. It is credited to its higher specific surface area and composite effect. Theoretically, decrease in band gap associated with increase in conductivity support the superiority of Au-Fe2O3 nanocomposite compared to the mother compound i.e., Fe2O3. In addition, electrochemical kinetic analysis showed that the charge-storage mechanism is mostly from a dominant capacitive process (78 % at 1.5 mV s-1). Solid-state asymmetric supercapacitor device has been fabricated using synthesized Au-Fe2O3 composite nanorod as positive and activated carbon as negative electrodes. The asymmetric solid-state device exhibits maximum energy density of 34.2 Wh kg-1 and power density of 2.73 kW kg-1 at current densities 1 A g-1 and 10 A g-1, respectively. Thus, the synthesized nanocomposite shows excellent activity as a supercapacitor with long term durability (91% capacitance retention) up to 5000 cycles even in acidic medium.
关键词： Shape-transformation,Redox mediated synthesis,Chemical stability,High power density/energy density,Au-Fe2O3 composite nanorod,Asymmetric supercapacitor
更新于2025-09-09 09:28:46
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Iron Oxide Nanoparticles as Potential Scaffold for Photocatalytic and Sensing Applications
摘要： Herein, we report photocatalytic and ?uorescence sensing applications of iron oxide (α-Fe2O3) nanoparticles synthesized by facile low-temperature simple solution process. The synthesized nanoparticles were characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) attached with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-visible spectroscopy and ?uorescence spectroscopy. The detailed analysis revealed that the synthesized nanoparticles were well-crystalline, grown in very high density and possessing rhombohedral α-Fe2O3 crystal structure. The prepared nanoparticles were used as ef?cient scaffold for photocatalytic and sensing applications. The detailed photocatalysis results revealed that in presence of an appropriate amount of α-Fe2O3 nanoparticles as photocatalyst, a signi?cant dye degradation of methyl orange (MO) was observed in 140 min. In addition, the fabricated ?orescence sensor based on α-Fe2O3 nanoparticles exhibited a low detection limit of ～3.33 μM/L towards picric acid. The observed results clearly con?rmed that the synthesized α-Fe2O3 nanoparticles are potential scaffold for photocatalysis and sensing applications.
关键词： Picric Acid,Photocatalysis,Methyl Orange,α-Fe2O3 Nanoparticles
更新于2025-09-04 15:30:14
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Photocharged Fe <sub/>2</sub> TiO <sub/>5</sub> /Fe <sub/>2</sub> O <sub/>3</sub> Photoanode for Enhanced Photoelectrochemical Water Oxidation
摘要： Photocharging is a novel and effective photoanode treatment to improve the photoelectrochemical water splitting performance. Here a photocharged Fe2TiO5/Fe2O3 photoanode was prepared with a significantly increased photocurrent density. Furthermore, the photocharging effect could also be deactivated via a discharging treatment under dark conditions. By using X-ray absorption spectroscopy and electrochemical impedance spectroscopy, the photocharging effect was revealed to be the formation of Fe(IV) intermediates at the interface to accelerate the water oxidation kinetics. The results offer a detailed understanding on the mechanism of the photocharging effect in hematite, which may help for the design of highly efficient water splitting catalysts.
关键词： photoanode,Fe2TiO5/Fe2O3,water oxidation,photocharging,photoelectrochemical
更新于2025-09-04 15:30:14
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Shaped Fe2O3 nanoparticles – synthesis and enhanced photocatalytic degradation towards RhB
摘要： Iron oxide nanoparticles of different shape were synthesized via an ion-mediated hydrothermal route. The addition of Zn2+ and Al3+ to the reaction system is no doubt the reason for the formation of hematite with cubic and disc structures, respectively. The growth mechanism of iron oxides is proposed. The morphology of the obtained nanostructures was analyzed by SEM and HR-TEM. The phase identification was performed by XRD and FTIR spectroscopy. Nanopowders were characterized by optical and zeta potential PZ measurements. The overall density of hydroxyl groups depends on the crystal structure and crystal faces. Placing oxides in the Rhodamine B RhB solution reduces the potential value PZ. The observed changes are the most pronounced for discs (ΔPZ=16.2 mV) and the least pronounced for cubes (ΔPZ=5.5 mV). A significant degree of adsorption of the dye on the surface of the discs, which confirms the presence of a significant number of hydroxyl groups responsible for surface activity. The photocatalytic activity of the obtained nanostructures investigated by photodecomposing RhB can be improved by applying H2O2 as an electron trap. Cyclic photodegradation experiments show that iron oxides with variously exposed planes can be used multiple times without losing their photocatalytic properties. Discs exhibited the most desirable photocatalytic behavior. Based on the performed addition of hydrogen peroxide, it seems that the shape of the particles affects the diffusion of H2O2 at the surface.
关键词： crystal,iron hydroxides,Fe2O3,nanostructures
更新于2025-09-04 15:30:14
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Magnetodielectric effect in a metamaterial consisting of xerogel with embedded ε-Fe2O3 iron oxide nanoparticles
摘要： The ε-Fe2O3 iron oxide is a fairly rare polymorphic modification, which only exists in the form of nanoparticles embedded, as a rule, into a silica gel matrix. This magnetically ordered iron oxide, which exhibits a significant room-temperature coercivity, is a ferroelectric; therefore, the magnetoelectric and magnetodielectric properties of this material evoke keen interest. In this work, we investigate the magnetodielectric (MD) effect in a metamaterial consisting of xerogel SiO2 with embedded ε-Fe2O3 nanoparticles 9 nm in size on average in a concentration of 20 mass.%. This bulk material exhibits the MD effect in a wide temperature range. The temperature behavior of the permittivity is related to the magnetic state of the ε-Fe2O3 oxide, which undergoes the magnetic transition from the magnetically hard to magnetically soft phase in the temperature range of 80–150 K, indicating the interplay of the ε-Fe2O3 magnetic and charge subsystems.
关键词： ε-Fe2O3,magnetodielectric effect,xerogel,multiferroics,nanoparticles
更新于2025-09-04 15:30:14
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Preparation of TiO2/Fe2O3/Chitosan Nanocomposite Films and Its Photocatalytic Degradation of Rhodamine B
摘要： A new photocatalytic thin films TiO2/Fe2O3/chitosan was synthesized by a solution casting technology to degrade the azo coloured compounds in the industrial waste water. The prepared TiO2/Fe2O3/chitosan was characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy (HRTEM). TiO2 and Fe2O3 were entrpped in the chitosan film uniformly. The catalytic ability of TiO2/Fe2O3/chitosan was evaluated by photodegradtion of Rhodamine B. About 99.4 % Rhodamine B were photodegraded by 0.5 g L-1 photocatalyst under solar lights irradiation for 120 min. The influence of the reaction pH has been well investigated. And TiO2/Fe2O3/chitosan has good stability and reusability, it is suitable for the practical industrial waste water treatment.
关键词： Photocatalytic degradation,Chitosan,Fe2O3,TiO2
更新于2025-09-04 15:30:14
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In situ fabrication of α-Fe2O3/CaFe2O4 p-n heterojunction with enhanced VOCs photodegradation activity
摘要： a-Fe2O3/CaFe2O4 p-n heterojunctions were prepared via a simple in-situ hydrolysis process as highly ef?cient VOCs degradation photocatalyst, wherein no additional conditions such as high pressure, high temperature and surfactants were required. The structures and morphologies of the as-prepared samples were analyzed by XRD, SEM and TEM. The results revealed that a-Fe2O3/CaFe2O4 p-n heterojunctions exhibited superior photocatalytic activity of VOCs degradation compared to pure CaFe2O4 and a-Fe2O3 in both steady model and ?ow bed model. It can degrade more than 82% of acetaldehyde within 180 min in steady mode and 65% in ?ow mode under visible light irradiation. The prominent VOCs remove property could be attributed to the strong interfacial contact caused by the in-situ fabrication process and the promoted charge carrier separation ef?ciency due to the constructing of a-Fe2O3/CaFe2O4 p-n heterojunction. It provides some new insights into the design and fabrication of advanced photocatalytic materials with p-n heterojunction for high ef?ciency in VOCs photodegradation.
关键词： VOCs photodegradation,In-situ fabrication,a-Fe2O3/CaFe2O4,p-n Heterojunction
更新于2025-09-04 15:30:14
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ZrO2/Fe2O3/RGO nanocomposite: Good photocatalyst for dyes degradation
摘要： We report a ZrO2/Fe2O3/RGO nanocomposite was synthesized via insitu-hydrothermal method and characterized by X-ray di?raction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), UV–Visible di?use re?ectance spectrophotometer (DRS), Raman, Photoluminescence (PL) and BET analysis to study the structural, morphological and optical properties. FESEM images declares that ZrO2 particles are uniform discs like nanostructure shape with clear facets and narrow size distribution; Fe2O3 were agglomerated, which leads to have completely dispersed with the rGO and forms a ZrO2/Fe2O3/RGO nanocomposite. The elemental composition (Zr, Fe, O and C) of as-prepared ZrO2/Fe2O3/RGO nanocomposite was con?rmed using EDX. FTIR and Raman analysis con?rmed the GO was reduced into RGO during the synthesis of ZrO2/Fe2O3/RGO nanocomposite. The synthesized catalysts were examined for photocatalytic activity by the degradation of Congo Red (CR) and Acetophenone (AP) under visible light illumination, these results clearly prompted that ZrO2/Fe2O3/RGO nanocomposite shows a high photodegradation e?ciency of CR and AP under visible light illumination than ZrO2/Fe2O3, pure Fe2O3 and pure ZrO2.
关键词： Hydrothermal,Raman,Photocatalytic degradation,Congo red and Acetophenone,ZrO2/Fe2O3/RGO nanocomposite
更新于2025-09-04 15:30:14
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Direct storage of holes in ultrathin Ni(OH) <sub/>2</sub> on Fe <sub/>2</sub> O <sub/>3</sub> photoelectrodes for integrated solar charging battery-type supercapacitors
摘要： Energy storage is a very significant issue for utilization of solar energy due to its discontinuous and unstable energy flux. Herein, for the first time, we propose a Fe2O3@Ni(OH)2 core–shell nanorod array as a photoelectrochemical battery-type supercapacitor for the direct storage of solar energy. Under light illumination, Fe2O3 absorbs solar energy and produces electron–hole pairs, while Ni(OH)2 stores the photo-generated holes, which can be released as electricity when the light is switched off. In addition, by controlling the valence band position of the semiconductor and the thickness of Ni(OH)2, the side reaction of water oxidation (electrolyte decomposition), which is harmful for the applications of a photoelectrochemical supercapacitor, can be completely suppressed. As a consequence, the specific capacitance of the Fe2O3@Ni(OH)2 photoelectrochemical supercapacitor is enhanced up to 20.6 mF cm?2 at a discharge current density of 0.1 mA cm?2, which is about 4.5 times that of BiVO4/PbOx reported in a previous study. This study offers a very promising device for the direct storage of solar energy and deepens our understanding on the interface charge transfer between a photoelectrode and a battery-type capacitive material.
关键词： water oxidation suppression,Fe2O3@Ni(OH)2,photoelectrochemical supercapacitor,core–shell nanorod array,solar energy storage
更新于2025-09-04 15:30:14