Pure Fe3O4 Research Articles

High Performance H2S Sensor Based on Ordered Fe2O3/Ti3C2 Nanostructure at Room Temperature.

The utilization of a heterogeneous nanojunction design has shown significant enhancements in the gas sensing capabilities of traditional metal oxide gas sensors. In this study, a novel room temperature H2S gas sensor employing Fe2O3 functionalized Ti3C2 MXene as the sensing material has been developed. This sensor exhibits a broad detection range (0.01-500 ppm), low detection limit (10 ppb), and rapid response/recovery times (10 s/15 s), making it ideal for ppb-level H2S detection. The exceptional gas sensitivity of Fe2O3/Ti3C2 composite to H2S can be attributed to several key factors. First, the unique layered frame structure of Fe2O3/Ti3C2 significantly amplifies the surface area of the hybrid material, enhancing the absorption and diffusion capabilities of H2S molecules. Second, the abundance of functional groups (-O, -OH, and -F) on the surface of Ti3C2 MXene nanosheets provides additional active sites for H2S adsorption, The density functional theory calculation confirms that the adsorption energy of the Fe2O3/Ti3C2 composite for H2S (-2.93 eV) is significantly lower than that of pure Fe2O3 (-2.37 eV) and Ti3C2 (-0.2 eV). Lastly, the remarkable metal conductivity of Ti3C2 MXene ensures efficient electron transfer, thereby enhancing overall sensing performance.

Controlled synthesis of 3D pseudocubic Fe2O3/BiFeO3 heterojunction photocatalyst for effective ciprofloxacin-HCl and methyl orange degradation

Nano-particle-based Iron (III) oxide (Fe2O3) and nanosheet-based bismuth ferrite (BiFeO3) photocatalysts were successfully prepared through a solid-state thermal decomposition approach. Especially, loading BiFeO3 over Fe2O3 demonstrated a 3D pseudocubic-based hierarchical architecture of Fe2O3/BiFeO3 (FeBiOx), which exhibits enhanced photodegradation efficiency of about 98.3 % for antibiotic ciprofloxacin-HCl (C-HCl) and 97.8 % for pollutant methyl orange (MO) under ultraviolet (UV) light irradiation within 180 and 150 min, respectively, compared to pure BiFeO3 and Fe2O3. The improved photocatalytic performance of FeBiOx was ascribed to the increased surface area, Type-II charge transfer scheme, effective charge migration efficiency induced by the surface plasmon resonance (SPR) effect of metal-Bi, and reduced bandgap energy.

Construction of visible-light-induced Fe2O3/g-C3N4 nanocomposites for the enhanced degradation of organic dyes: Optimization of operative parameters

This research aims to develop the highly promising Fe2O3/g-C3N4 photocatalyst through hydrothermal techniques to cope with the elevated amounts of bromophenol blue (BPB) dye in wastewater. The morphological studies were carried out by SEM analysis, while the crystallinity, structural behavior, and oxidation states of the prepared materials were determined by XRD, FTIR, and XPS analysis. The hydrodynamic size, surface area, and magnetic characteristics of the constructed materials were assessed through DLS, BET, and VSM analysis. The effectivity of the synthesized Fe2O3 and Fe2O3/g-C3N4-30 photocatalysts was appraised by the abatement of BPB under visible light radiation for 48 min. The results have shown an excellent degradation efficacy of Fe2O3/g-C3N4-30 photocatalyst with 98.39 % of BPB removal and a rate constant of 0.0757 min−1, which was much higher than Fe2O3 photocatalyst with 79.64 % of removal and a rate constant of 0.0335 min−1 under optimum conditions. The enhancement in degradation efficiency of the Fe2O3/g-C3N4-30 was due to the large surface area of Fe2O3/g-C3N4-30 (106.94 m2/g) as a result of g-C3N4 inclusion in the material, while the pure Fe2O3 unveiled a surface area of 89.67 m2/g. The impact of different reaction parameters on BPB degradation was also investigated, while the contribution of free radicals was corroborated through radical trapping experiments. The Fe2O3/g-C3N4-30 exhibited tremendous stability for repeated applications, with a loss of 8.03 % in efficiency after five consecutive experiments because of its easy magnetic separation. The experimental results have shown that synthesized Fe2O3/g-C3N4-30 photocatalysts could be used for the effective degradation of BPB from wastewater.

Microstructural characteristics of the internal oxidation zone of ferritic/martensitic steel exposed to LBE at 550°C for 1000 h

The oxidation products formed on ferritic/martensitic (F/M) steel exposed to oxygen-saturated lead-bismuth eutectic (LBE) at 550 °C for 1000 h were investigated using various characterizations. The results indicate that the corrosion products consist of three distinct layers from the inside to the outside: the inner oxidation zone (IOZ), a middle oxide layer, and the growth front facing LBE. In the IOZ, although O has penetrated the entire oxidation layer, the martensite laths and ferrite grains remain visible. However, significant segregation of Cr and O along the laths and grain boundaries has occurred, resulting in the formation of strip-shaped Cr2O3 particles. In the matrix adjacent to the IOZ, Cr atoms have segregated at the grain boundaries and martensite laths, forming Cr-rich regions, while O atoms have not yet infiltrated. During the growth of Fe3O4 grains, the priority formed strip-shaped Cr2O3 particles are pushed toward the corrosion front until they detach from the F/M steel and disperse into the LBE, resulting in nearly pure Fe3O4 grains in the middle layer. The gradient three-layer structure of the oxidation product is closely associated with the segregation of Cr and the gradient distribution of oxygen partial pressure (PO2).

Fe2O3/In2O3 composite materials for dual-selective detection of H2S and NO2: Study on sensing mechanisms and sensing transition

Developing concise and efficient dual-selective gas sensors has been a significant challenge in sensing technology. In this study, a Fe2O3/In2O3 (FIO) composite material was successfully synthesized via a water bath method for highly efficient dual-selective detection of H2S and NO2. The enhanced dual-selectivity of the composite material is attributed to the high-quality heterojunction formed at the Fe2O3 and In2O3 interface, which provides more active sites and optimizes the electronic structure, thereby greatly improving electron transport efficiency. Consequently, this unique structure significantly enhances the gas sensing response and stability of the composite material. The optimal FIO-3 composite shows significant responses: 14.7 at 80 °C with 100 ppm H2S and 64.3 at 100 °C with 700 ppb NO2, achieving 7- and 31-fold improvements over pure Fe2O3. Analysis indicates that the dual-selective response of the FIO composite material is attributed to synergistic enhancement mechanisms, primarily controlled by high-temperature activation effects. Further density functional theory (DFT) studies reveal changes in charge density at the composite material interface, particularly facilitated by the formation of oxygen bridges promoting electron transfer from In2O3 to Fe2O3. This study offers new insights into the sensing transition of dual-selective gas sensors.

Harnessing the synergistic effect of CuO@Fe3O4/n-Si for high-efficiency photodiodes

High-performance photodetectors were fabricated using drop-casting method, employing pure CuO, Fe3O4 and CuO@Fe3O4 nanocomposite (NC). These devices aim to achieve enhanced responsivity (R), photosensitivity (Ps), detectivity (D∗), and external quantum efficiency (EQE). The XRD results indicate that the crystallite size of the CuO@Fe3O4 NC was reduced to around 20 nm, compared to 23 nm for pure CuO and 25 nm for pure Fe3O4. In addition, phase purity and functional groups were corroborated by Raman and FTIR analysis, supporting these findings. The bandgap energy of pure CuO and Fe3O4 was estimated to be around 1.25 and 1.22 eV, respectively, while the CuO@Fe3O4 NC exhibited a lower bandgap energy of 1.13 eV due to the interface between CuO and Fe3O4. Notably, the fabricated CuO@Fe₃O₄/n-Si photodiode exhibited excellent rectification properties under illumination, with an ideality factor (n) of 2.87 and a barrier height (ΦB) of 0.83 eV. The device achieved high Ps of 773.4 %, R of 542.6 mA/W, EQE of 208.7 %, and D∗ of 2.91 × 1012 Jones, demonstrating that the CuO@Fe3O4 NC is the most effective material for photodetection in this study.

Boosting adsorption of ciprofloxacin on Fe3O4 nanoparticles modified sepiolite composite synthesized via a vacuum-filtration assisted coprecipitation strategy

Treatment of antibiotics-containing wastewater is imperative for ensuring environmental and public health. However, effectively removing antibiotics in environment is still a great challenge. Fabrication of sepiolite-supported iron oxide nanomaterials with large specific surface area and high reactivity is a promising solution for efficient antibiotics removal. In this work, a highly dispersed Fe3O4 nanoparticle modified sepiolite composite (Fe3O4-sep-vacuum) was synthesized in-situ by employing a novel vacuum-filtration assisted coprecipitation strategy for the first time. Fe3O4-sep-vacuum exhibited the highest adsorption capacity to ciprofloxacin compared with those of pure Fe3O4 nanoparticles, sepiolite, and those composites obtained by traditional coprecipitation methods. Approximately 93 % of CIP (20 mg/L) could be removed by Fe3O4-sep-vacuum within 20 min at initial pH 6.0. The kinetic and adsorption isotherms followed pseudo-second-order and Temkin models, respectively. The maximum adsorption capacity (qm) of Fe3O4-sep-vacuum for CIP was 18.4 mg/g at initial pH 6.0. The solution pH, temperature, coexisting divalent cations, and HA concentration were demonstrated to play substantial roles in the adsorption processes of ciprofloxacin on Fe3O4-sep-vacuum surface. The Fe3O4-sep-vacuum maintained excellent stability and reusability during CIP adsorption process. Electrostatic interactions play a decisive role in the adsorption process of ciprofloxacin by Fe3O4-sep-vacuum. Hydrogen bonds and hydroxyl groups on the Fe3O4-sep-vacuum surface also play important roles in the adsorption process of ciprofloxacin. Fe3O4-sep-vacuum also exhibited excellent adsorption capacity to ofloxacin. These results indicate that the vacuum-filtration assisted coprecipitation strategy could be used to fabricate monodispersed nanoparticles modified sepiolite composites, which could be acted as promising materials for highly efficient remediating antibiotics contaminated wastewater.

Devolopment of Co-doped Fe2O3 Nanoparticles for Electrochemical Supercapacitor

Co-doped Fe2O3 nanoparticles were synthesized by the co-precipitation method. These crystalline nanostructures were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The electrochemical characteristics include charge–discharge cycling, which improves the conductivity and capacitance for the high-performance supercapacitor. The CV analysis of the pure Fe2O3 and Co-doped Fe2O3 electrode was distinctive in the 1 M KOH solution case. The nanoparticle size electrode reveals enhanced specific capacitance compared to Co-doped Fe2O3 and Fe2O3 to the electrode has a specific capacitance of about 33.50 F×g-1 and 13.74 F×g-1 with a scan rate 5 mV×s-1. Keywords: Supercapacitor, Co-precipitation method, Electrochemical, Energy storage

Synthesis of varied oleic acid-coated Fe3O4 nanoparticles using the co-precipitation technique for biosensor applications

This study successfully synthesized oleic acid (OA)-coated Fe3O4 nanoparticles using the coprecipitation method for the needs of biosensor applications, as shown through the characterization of structure and morphology using XRD and TEM. This observation used 0.75 ml of OA (Fe3O4-OA(0.75)) and 1.25 ml of OA (Fe3O4-OA(1.25). A decrease in particle size distribution from 18.55 nm to 16.30 nm was observed, which means a reduction in agglomeration and increased dispersibility. Vibrating Sample Magnetometer (VSM) observations showed that the saturation magnetization of Fe3O4 particles modified with OA decreased from 47.71 emu/g to 45.90 emu/g at Fe3O4-OA(0.75) and decreased again to 42.29 emu/g at Fe3O4-OA(1.25). But they all show soft ferromagnetic properties with very low coercivity, making them suitable for Giant Magnetoresistance (GMR) biosensor applications. A series of concentrations in ethanol solution were performed to evaluate the detection sensitivity of GMR for these pure and oleic acid-modified Fe3O4 samples. Concentrations of 2, 5, 10, 15, 25, and 35 mg/ml were integrated at 2 μL each onto the surface of the GMR chip. A decrease in sensitivity was observed due to the change in saturation. Pure Fe3O4 with a sensitivity of 5.07 mV (mg/ml) decreased to 4.49 mV (mg/ml) and 3.35 mV (mg/ml) after oleic acid coating. Thus, although adding a proportional amount of oleic acid can slightly decrease the saturation magnetization, it can be a valuable method for applications such as GMR biosensors that demand high dispersibility and sensitivity that remains strong.

Hydrothermal and electrochemical synthesis of Fe2O3 and ZnFe2O4/Fe2O3 photoanodes for photoelectrochemical applications: An experimental and theoretical study

Hematite (Fe2O3) is commonly utilized in the fabrication of photoelectrochemical cells for water-splitting reaction. However, its relatively low efficiency has highlighted the necessity for enhancements in Fe2O3-based photoanodes. In addressing this issue, this study implemented the addition of ZnFe2O4. The pure Fe2O3 was synthesized onto a Fluorine-doped Tin Oxide coated glass by the hydrothermal process, followed by the synthesis of various ZnFe2O4/Fe2O3 heterostructures using electrochemical deposition techniques. The thin film’s composition, surface morphology, and chemical species of the products were analyzed using X-ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, and X-ray Photoelectron Spectroscopy, respectively. The performance of the Fe2O3-based photoanode was compared to that of various ZnFe2O4/Fe2O3 photoanodes through photoelectrochemical studies. Results indicated that a 50 s electrochemical deposition of ZnFe2O4 on Fe2O3 yielded the highest photoconversion efficiency. Additionally, Density Functional Theory was employed to investigate the electron energy level of ZnFe2O4, revealing alignment with the properties of Fe2O3. Theoretical analysis showed that the Fermi energy of ZnFe2O4 exceeded that of Fe2O3, suggesting a preferable direction for electron transfer from ZnFe2O4 to Fe2O3 which was in consistent to the Mott-Schottky analysis. The performance of the overall ZnFe2O4/Fe2O3 heterostructure photoanodes demonstrated greater efficiency compared to pristine Fe2O3.

Bimetallic Ag/Fe-MOG derived flake-like Ag2O/Fe2O3 p-n heterojunction for efficient photodegradation organic pollutants within a wide pH range

In this paper, we reported a facile and clean strategy to prepare the flake-like Ag2O/Fe2O3 bimetallic p-n heterojunction composites for photodegradation organic pollutants. The surface morphology, crystal structure, chemical composition and optical properties of Ag2O/Fe2O3 were characterized by SEM, high-resolution TEM images with EDX spectra, XRD, XPS, FT-IR and UV–vis DRS spectra respectively. The formation of Ag2O/Fe2O3 p-n heterojunction facilitated the interfacial transfer of electrons as well as the separation of charge carries. Hence, the as-synthesized Ag2O/Fe2O3-3 composites exhibited ultra-high photocatalytic activity. Under the experimental conditions of catalyst dosage of 0.4 mg mL−1 and irradiation time of 60 min, the degradation conversion rate of rhodamine B reached 96.1 %, which was 5.0 and 2.8 times of pure phase Ag2O and Fe2O3, respectively. Meanwhile, the degradation performance of Ag2O/Fe2O3-3 was not limited by pH, and it can achieve high degradation efficiency under 3–11. In addition, Ag2O/Fe2O3-3 also showed superb degradation ability for other common anionic dyes, cationic dyes and antibiotics. XPS and FT-IR spectra showed that Ag2O/Fe2O3-3 retained a carbon skeleton that facilitated electron transport and light absorption conversion. And the analyses of quenching experiment and EPR demonstrated •O2−, •OH and h+ were crucial reactive oxidant species contributing to the rapid organic pollutant degradation. This work provides new insights into obtaining p-n photocatalysts heterojunction with excellent catalytic activity for removing organic pollutants from wastewater.

Harnessing chemical functionality of xylan hemicellulose towards carbohydrate polymer-based pH/magnetic dual-responsive nanocomposite hydrogel for drug delivery

This study reports a pH/magnetic dual-responsive hemicellulose-based nanocomposite hydrogel with nearly 100 % carbohydrate polymer-based and biodegradable polymer compositions for drug delivery. We synthesized pure Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) using a co-precipitation method, then engineering xylan hemicellulose (XH), acrylic acid, poly(ethylene glycol) diacrylate, and Fe3O4 to synthesize the pH/magnetic dual-responsive hydrogel (Fe3O4@XH-Gel), through graft polymerization on XH with in-situ doping Fe3O4 MNPs initiated by the ammonium persulfate/tetramethylethylenediamine redox system. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectrometer (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), swelling gravimetric analysis, vibrating sample magnetometer (VSM) were employed to analyze the hydrogel's chemical structures, morphologies, pH-responsive behaviors, and magnetic responsiveness characteristics, mechanical and rheological properties, as well as cytotoxicity and biodegradability. The results indicate that the Fe3O4@XH-Gel exhibited excellent dual responsiveness to pH and magnetism. Furthermore, an emphasis was placed on the in-depth analysis of the pH response mechanism. Finally, we utilized this cutting-edge hydrogel to investigate the controlled-release behavior of two model drugs, Acetylsalicylic acid and Theophylline. The hydrogel demonstrated exceptional controlled release attributes, positioning it as a potential carrier for targeted drug delivery, particularly to the gastrointestinal conditions.

Synthesis of Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres for efficient aqueous phenol photocatalytic degradation

This study aims to synthesize a ternary Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres by modified Stöber technique to photodegrade aqueous phenol under UV-C light effectively. Results of the X-ray diffractogram of the as-synthesized Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres showed the nanoparticles having an average size of 126.00 nm, comparable to 150.00 nm seen in the FESEM micrograph. These sizes were supported by the EDX and FTIR results which verified the presence of Fe3O4, rGO, and SiO2, and the TEM micrograph revealed them to be spherically shaped. Also, the thermally more stable microspheres than the pure individual components and binary nanocomposites were evident in their corresponding TGA thermograms.Similarly, the photoluminescence spectra of the Fe3O4-NH2-APTES@rGO@SiO2 microspheres supported their higher photodegrading ability as a consequence of an extended e-/h+ recombination rate. The microspheres were more effective in photo-catalytically degrading the highest amount of aqueous phenol (∼89 %) than Fe3O4-NH2-APTES@rGO (∼74 %), Fe3O4-NH2-APTES@SiO2 (∼78 %), and pure Fe3O4 (∼62 %), under an optimized condition of 0.2 g/350 mL catalyst loading and 50 ppm of initial phenol concentration. The enhanced photoactivity was ascribed to the high stability and specific surface of SiO2, the synergistic influence of Fe3O4, and the rGO sheet’s rapid electron transport·H2O2 enhanced phenol degradation to 94 %.

A novel Fe2O3@CeO2 heterojunction substrate with high surface‐enhanced Raman scattering performance

AbstractSurface‐enhanced Raman scattering (SERS) has been applied in many fields due to its advantages of fast and nondestructive detection. For semiconductors, the large‐scale electron‐hole pair separation of heterojunction is conducive to efficient charge transfer, which is a promising SERS substrate. Here, we designed a Fe2O3@CeO2 heterojunction substrate by hydrothermal method and explored its enhancement mechanism in detail. α‐Fe2O3 is a promising semiconductor with a narrow bandgap, and CeO2 has adequate oxygen vacancies on the surface. Combing α‐Fe2O3 and CeO2 into a shell‐core structure, Fe2O3@CeO2 heterojunction presents higher SERS performance than pure Fe2O3 and CeO2 for methyl orange (MO) molecule with a limit of detection (LOD) of 5 × 10−8 mol/L. Under the excitation of 514 nm, Fe2O3 can produce an effective exciton resonance due to its narrow bandgap (2.01 eV). The oxygen vacancy in CeO2 acts as the active site to promote the adsorption of molecules and facilitate the photo‐induced charge transfer (PICT) between the substrate and MO molecules. Therefore, the high SERS performance of Fe2O3@CeO2 heterojunction is achieved due to the coupling effect of excitons resonance, molecular resonance, and PICT resonance. It is found that Fe2O3@CeO2 has good SERS performance and stability to organic pesticides, especially metamitron (LOD = 5 × 10−9 mol/L). This work combines the advantages of Fe2O3 being prone to producing photoelectrons and abundant oxygen vacancies of CeO2, providing a reference for designing semiconductor SERS.

Towards High-Performance Photo-Fenton Degradation of Organic Pollutants with Magnetite-Silver Composites: Synthesis, Catalytic Reactions and In Situ Insights.

In this study, Fe3O4/Ag magnetite-silver (MSx) nanocomposites were investigated as catalysts for advanced oxidation processes by coupling the plasmonic effect of silver nanoparticles and the ferromagnetism of iron oxide species. A surfactant-free co-precipitation synthesis method yielded pure Fe3O4 magnetite and four types of MSx nanocomposites. Their characterisation included structural, compositional, morphological and optical analyses, revealing Fe3O4 magnetite and Ag silver phases with particle sizes ranging from 15 to 40 nm, increasing with the silver content. The heterostructures with silver reduced magnetite particle aggregation, as confirmed by dynamic light scattering. The UV-Vis spectra showed that the Fe:Ag ratio strongly influenced the absorbance, with a strong absorption band around 400 nm due to the silver phase. The oxidation kinetics of organic pollutants, monitored by in situ luminescence measurements using rhodamine B as a model system, demonstrated the higher performance of the developed catalysts with increasing Ag content. The specific surface area measurements highlighted the importance of active sites in the synergistic catalytic activity of Fe3O4/Ag nanocomposites in the photo-Fenton reaction. Finally, the straightforward fabrication of diverse Fe3O4/Ag heterostructures combining magnetism and plasmonic effects opens up promising possibilities for heterogeneous catalysis and environmental remediation.

Synergistic boost in Fe3O4 anode performance for li-ion batteries via Zn and Cu double doping and multi-walled carbon nanotube composite integration

In this study, a novel nanocomposite material comprising pure Fe3O4 (FO), doped Zn0.5Cu0.5Fe2O4-3 (ZCFO-3), and Zn0.5Cu0.5Fe2O4-3@ Multi-walled carbon nanotube (ZCFO-3@MWCNT) nanocomposite material is carefully prepared using a simple one-step hydrothermal process. Comprehensive surface and morphological analysis are conducted using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and High-resolution transmission electron microscopy (HRTEM), while compositional studies are investigated through Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrochemical performance is fully analyzed through Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), rate capability tests, discharge/charge capacity, and cyclic stability evaluations. Among these three nanomaterials, ZCFO-3@MWCNT nanocomposite at 100 mA g−1 current density reveals the best performance, with a discharge capacity of 1974 mAh g–1, ZCFO-3 and FO reveal 1340 mAh g–1 and 1317 mAh g–1 respectively. After 800 cycles at 500 mA g−1 current density, ZCFO-3@MWCNT stays strong with a discharge capacity of 646 mAh g–1, while ZCFO-3 manages only 362 mAh g–1 and FO only 111 mAh g–1. After 1200 cycles at 500 mA g−1, the nanocomposite still delivers 518 mAh g–1. This study suggests that ZCFO-3@MWCNT could be a promising anode material for lithium-ion batteries.

Chemical looping reforming of the micromolecular component from biomass pyrolysis via Fe2O3@SBA-16

AbstractTo solve the problems of low gasification efficiency and high tar content caused by solid–solid contact between biomass and oxygen carrier in traditional biomass chemical looping gasification process. The decoupling strategy was adopted to decouple the biomass gasification process, and the composite oxygen carrier was prepared by embedding Fe2O3 in molecular sieve SBA-16 for the chemical looping reforming process of pyrolysis micromolecular model compound methane, which was expected to realize the directional reforming of pyrolysis volatiles to prepare hydrogen-rich syngas. Thermodynamic analysis of the reaction system was carried out based on the Gibbs free energy minimization method, and the reforming performance was evaluated by a fixed bed reactor, and the kinetic parameters were solved based on the gas–solid reaction model. Thermodynamic analysis verified the feasibility of the reaction and provided theoretical guidance for experimental design. The experimental results showed that the reaction performance of Fe2O3@SBA-16 was compared with that of pure Fe2O3 and Fe2O3@SBA-15, and the syngas yield was increased by 55.3% and 20.7% respectively, and it had good cycle stability. Kinetic analysis showed that the kinetic model changed from three-dimensional diffusion to first-order reaction with the increase of temperature. The activation energy was 192.79 kJ/mol by fitting. This paper provides basic data for the directional preparation of hydrogen-rich syngas from biomass and the design of oxygen carriers for pyrolysis of all-component chemical looping reforming.

Novel magnetic separable BiOBr@Fe3O4 p-n heterostructure with highly efficient photocatalytic property toward organic pollutants

In this work, by considering good photocatalytic activity and p-type property but insufficient visible light absorbing property of BiOBr and excellent light absorption, n-type property of Fe3O4 that has poor photocatalytic property due to fast recombination of charge carriers having narrow bandgap, a solar light-active BiOBr@Fe3O4 p-n heterostructure was designed and synthesized for the first time using a versatile chemical precipitation method, combining the p-type BiOBr with the n-type Fe3O4. The developed photocatalyst underwent comprehensive investigation using various high-precision techniques. Its photocatalytic properties were assessed for the photodegradation of organic contaminants, such as Congo red (CR) and rhodamine B (Rh B), under solar light irradiation. The degree of mineralization of these pollutants by the BiOBr@Fe3O4 p-n heterostructure during photodegradation was also evaluated. Additionally, the photodegradation pathway was examined using LC-MS, and a possible mechanism were proposed. The findings reveal that the developed BiOBr@Fe3O4 p-n heterostructure exhibited exceptional photocatalytic performance, degrading 100% and 81% of Rh B and CR, respectively. Kinetic findings also indicate that the rate of photodegradations of the pollutants by the BiOBr@Fe3O4 heterostructure is approximately 7.2 and 3.4 times higher than that of pure Fe3O4 for the degradation of CR and Rh B, respectively. Besides, the developed heterojunction exhibited better photocatalytic performance than existing photocatalysts for photodegradation of CR and Rh B. The total organic carbon content (TOC) analysis further demonstrates the exceptional mineralization properties of the fabricated photocatalyst toward the pollutants. Therefore, the developed BiOBr@Fe3O4 p-n heterostructure shows promise in the treatment of these organic pollutants, contributing significantly to environmental remediation, particularly in photocatalysis.

Preparation of CsPbBr3@Fe2O3 heterojunction nanocrystals for ppb-level H2S sensing

Metal-halide perovskite (MHP) nanocrystals (NCs) have unique advantages in the gas sensing field, but the poor stability restricts their widespread applications. In this work, the CsPbBr3@Fe2O3 heterojunction NCs were synthesized successfully by simple solution process and subsequent surface modification strategy for constructing a gas sensor. The Fe2O3 shell layer was obtained through thermal decomposition of acetylacetone iron (AAI) at 400 °C. The resulting CsPbBr3@Fe2O3 heterostructured NCs exhibit a higher gas-sensing performance to H2S than pure CsPbBr3 and Fe2O3, respectively. Upon exposure to 10 ppm H2S, the response value of 4.12 was obtained at a moderate working temperature of 350 °C, while the response was fast both in terms of response time and recovery time, i.e., 1.84 s and 24.20 s, respectively. This might be the best performance for MHP sensors, to the best of our knowledge. The excellent gas-sensitive response might be attributed to the formation of a heterojunction which promotes the electron migration from CsPbBr3 to Fe2O3.

Z-scheme S-modified Zn0.2Cd0.8S/α-Fe2O3 heterostructure for enhanced photoelectrochemical water oxidation

A Z-type heterojunction system is proven to be an efficient strategy to promote the separation of photo-generated carriers and maintain strong redox capacity for an enhanced photoanode. Herein, we synthesized a S-modified Fe2O3/Zn0.2Cd0.8S (Fe/ZCS) photoanode by one-pot hydrothermal treatment of FeOOH/Zn0.2Cd0.8S precursor film, followed by vapor deposition treatment. The as-synthesized S-modified Fe/ZCS displayed enhanced PEC water oxidation performance with a photocurrent density (2.76 mA cm−2) of about 2.63 times that of a pure phase Fe2O3 and 2.05 times that of Fe/ZCS at 1.23 VRHE. After 8 h of continuous operation, the photocurrent density retention rate was still 96.4 % demonstrating its satisfactory stability. Benefiting from the morphology of fine nanorods, the fabricated Z-scheme heterostructure exhibited strong oxidation–reduction ability and the well-distributed Fe(III)-SO42- bonds played key roles as the electron capture centers. The fabricated Z-scheme photoanode exhibited prospective applications in sustainable photoelectrochemical water oxidation.