Fe2O3 Nanosheets Research Articles

Label-free electrochemical biosensor with magnetic self-assembly constructed via PNA-DNA hybridization process on α-Fe2O3/Fe3O4 nanosheets for APOE ε4 genes ultrasensitive detection

Label-free electrochemical biosensor with magnetic self-assembly constructed via PNA-DNA hybridization process on α-Fe2O3/Fe3O4 nanosheets for APOE ε4 genes ultrasensitive detection

Spin Transport Modulation of 2D Fe3O4 Nanosheets Driven by Verwey Phase Transition.

Realizing spin transport between heavy metal and two-dimensional(2D) magnetic materials at high Curie temperature (TC) is crucial to advanced spintronic information storage technology. Here, environmentally stable 2D nonlayered Fe3O4 nanosheets are successfully synthesized using a reproducible process and found that they exhibit vortex magnetic domains at room temperature. A Verwey phase transition temperature (TV) of ≈110 K is identified for ≈3nm thick nanosheet through Raman characterization and spin Hall device measurement of the Pt/Fe3O4 bilayer. The anisotropic magnetoresistance ratio decreases near TV, while both the spin Hall magnetoresistance ratio and spin mixing conductance (Gr) increase at TV. As the temperature approaches 112 K, the anomalous Hall effect ratio tends to become zero. The maximum Gr reaches ≈5 × 1015 Ω-1m-2 due to the clean and flat interface between Pt and 2D nanosheet. The observed spin transport behavior in Pt/Fe3O4 spin Hall devices indicates that 2D Fe3O4 nanosheets possess potential for high-power micro spintronic storage devices applications.

Effect of cyclic oxidation temperature on compressive strength of Cu-based brake pad for high-speed train

The cyclic oxidation tests of Cu-based brake pads at temperatures of 25, 300, 400, 500, 550, 600, 650 and 700 °C were conducted to simulate the oxidation of the friction surface under different braking speeds. Furthermore, the effect of cyclic oxidation temperature on the compressive strength was investigated. The results show that the cyclic oxidation process of Cu-based brake pads can be divided into three stages: mild oxidation (≤400 °C), moderate oxidation (500–600 °C) and severe oxidation (≥650 °C). Mild oxidation results in the formation of spherical Cu2O particles. The surface is covered by Cu2O and Fe2O3 nanosheets for moderate oxidation. Severe oxidation is characterized by a continuous thick CuO film, Fe2O3 nanosheets, and eroded graphite particles. The compressive strength and toughness of Cu-based brake pads show a declining trend as the cyclic oxidation temperature rises. The compressive strength of the Cu-based brake pad after oxidized at 700 °C, recorded at 30.56 MPa, is considerably lower than that of the original samples, which was 132.2 MPa. This reduction in compressive strength is attributed to the embrittlement of the metallic matrix and the formation of pores from graphite oxidation.

Sustainable Modification of Naturally Available Resources for Metal-Ion Storage Applications

The adoption of naturally abundant resources for energy storage applications represents a pivotal strategy in advancing large-scale sustainable green energy solutions across diverse sectors. This presentation provides an overview of E2MC's approaches to the green modification of naturally occurring materials at a low cost, focusing on their metal-ion energy storage capabilities. Key natural materials discussed include molybdenum disulfides (MoS2), ilmenite and natural graphite minerals, as well as corn waste. (a) The thermal oxidation of MoS2 is explored as a straightforward and effective method to produce layer-structured molybdenum trioxide (α-MoO3) with crystalline defects, showing enhanced Li-ion storage kinetics. The molten salt treatment of MoS2 produces sodium dimolybdate with improved Li-ion and Na-ion storage performances. Additionally, a hybrid nanostructure comprising metastable monoclinic molybdenum trioxide (β-MoO3), hexagonal MoS2 secondary crystals and graphene nanosheets is produced through mechanochemical-molten salt treatment. This hybrid structure exhibits an interesting Li-ion storage performance. (b) Carbonization of largely available corn lignocellulosic waste in the presence of molten salt is discussed as a facile approach for the preparation of biocarbons with appropriate specific surface area, pore volume, and elemental carbon purity. The partial dissolution of biomass impurities into the molten salt enhances the Li-ion and Na-ion storage performance of the biocarbon. Additionally, the treatment of corn-derived silica with Fe2O3 and graphite-derived graphene nanosheets, leads to the preparation of a nanostructure in which ferric oxide particles are coated with iron silicate, and these hybrid nanostructures are integrated with graphene nanosheets, showcasing an interesting Li-ion storage performance. (c) Efficient exfoliation of naturally available graphite minerals in molten salt is introduced leading to the formation of carbon nanostructures with promising applications in both Li-ion and Na-ion storage. The economic and strategic advantages associated with utilizing such naturally available resources for energy storage applications are also discussed. References W. Zhu, A.R. Kamali*, J. Alloy Compd. 932 (2023) 167724W. Zhu, A.R. Kamali*, J Alloy Compd. 968 (2023) 171823A.R. Kamali*, H. Zhao, J. Alloy Compd. 949 (2023) 169819W. Zhu, A.R. Kamali*, J. Alloy Compd. 831(2020) 154781H. Zhao, A. Rezaei, A.R. Kamali*, J. Electrochem. Soc. 169 (2022) 054512A.R. Kamali*, J. Ye, Miner. Eng. 172 (2021) 107175S. Li, A.R. Kamali*, Chem. Eng. Sci. 265 (2023) 118222S. Li, A.R. Kamali*, Gels 9 (2023) 701S. Li, A.R. Kamali*, Colloids Surf. A 656 (2023) 130275H. Fu, A.R. Kamali* et al, Chem. Eng. J. (2023) 146936W. Zhu, A.R. Kamali*, J. Electrochem. Soc. 168 (2021) 046517

Synergistically coupled CoMo/Fe2O3 electrocatalyst for highly efficient and stable overall water splitting

Constructing bifunctional non-precious metal electrocatalysts with advanced industrial value and excellent electrocatalytic performance to achieve efficient overall water splitting is important but difficult. Herein, a heterogeneous electrocatalyst comprising of CoMo alloys anchored Fe2O3 nanosheets was prepared by hydrothermal and electrodeposition methods. The strongly coupled interfaces between the CoMo alloys and Fe2O3 nanosheets promote charge redistribution, which could improve electron transfer efficiency and accelerate reaction kinetics, potentially optimizing reactant adsorption energy. Further density functional theory (DFT) calculations reveal that the construction of CoMo/Fe2O3/NF heterostructured catalyst facilitates to promote interfacial charge redistribution and enhance charge transfer capacity, thus boosting the catalytic performance. Benefiting from this, the optimal CoMo/Fe2O3/NF heterostructure demonstrates a minimal overpotential of 71 mV at 10 mA cm−2 for the HER and 266 mV at 50 mA cm−2 for the OER. Remarkably, the catalyst served as a bifunctional electrode for water splitting, resulting in a cell voltage down to 1.5 V at a current density of 10 mA cm−2. This research provides an effective way for the construction of non-precious iron oxides-based bifunctional electrocatalysts using alloy/metal oxide interfacial engineering strategy.

The synergistic enhancement of photocatalytic activity by Fe3O4–TiO2 nanosheets for rhodamine B degradation

As an advanced oxidation material, Fe3O4-TiO2 nanocomposites have been widely used in wastewater treatment. However, conventional Fe3O4 nanoparticles suffer from drawbacks such as carrier recombination and aggregation, which seriously affect the catalytic activity. In this study, Fe3O4-TiO2 nanosheets with different TiO2 loading rates were synthesized by sol-gel method and solvothermal method. The unique two-dimensional nanostructure of Fe3O4 nanosheets facilitated the deposition of TiO2 nanoparticles, resulting in Fe3O4-TiO2 nanosheets with a high BET specific surface area of 121.67 m2·g−1. Under optimal experimental conditions, the degradation rate of RhB dye in the photocatalytic synergistic Fenton-like system constructed with Fe3O4-TiO2 nanosheets reached 98.12 % within 120 min, significantly surpassing that of single photocatalysis and Fenton-like systems. It was attributed to the unique surface structure of Fe3O4 nanosheets, which provided a larger contact area for TiO2 nanoparticles. It facilitated the effective reduction of Fe3+ to Fe2+ by photogenerated electrons in TiO2, inhibited the recombination of photogenerated electron-hole pairs, and consequently enhanced the degradation rate of RhB dye. Furthermore, Fe3O4-TiO2 magnetic nanosheets exhibited excellent reusability and stability, with the recovery rate and degradation rate of RhB dye remaining above 90 % even after five cycles. More importantly, the catalytic mechanism of Fe3O4-TiO2 nanosheets was elucidated, and •OH identified as the primary reactive species responsible for degrading RhB dye. This work provides a novel research direction for designing and preparing advanced catalytic degradation materials, offering a practical solution to the challenging issue of wastewater treatment.

Two-dimensional iron oxide/graphene-based nanocomposites as high-performance solid lubricants

Beyond conventional 2D layered materials such as graphene and transition metal dichalcogenides, 2D metal oxides have also received much interest in recent years. They have unique electronic (such as 2D TiO2 and MoO2), catalytic (such as 2D CeO2 and MnO2), and magnetic properties (such as 2D Fe2O3) compared with bulk metal oxides due to their atomically thin structures. Certain types of 2D metal oxides also have the potential to be a new type of high-performance solid lubricants due to the tunable interlayer interaction and possibility for 2D heterostructure formation, but this remains largely unexplored. In this work, we developed a scalable microwave-assisted solid-state synthesis of 2D Fe2O3 and their nanocomposites with reduced graphene oxide (rGO). The 2D Fe2O3/rGO nanocomposites were systematically characterized by electron microscopies and spectroscopies, and their utilization as solid lubricants was studied by pin-on-disk tribometer on both silicon and steel substrates. The results show that due to the easy sliding between 2D Fe2O3 and rGO nanosheets and their unique magnetic-induced assembled morphology, low coefficient of friction (COF) can be achieved for both steel-silicon and steel-steel interfaces. Superlubricity (COF ∼ 0.007) can be achieved for the 2D Fe2O3/rGO nanocomposite with a GO primer layer on a steel substrate. This work provides new insights into the development of functional 2D nanocomposites and expands their applications to solid lubrication and beyond.

Outstanding performance of magnetic La2O2CO3/Fe3O4 nanosheets for simultaneous removal of phosphate and arsenate from wastewater

The chemical similarities and co-occurrence of phosphate and arsenate contamination have heightened the focus on their efficient simultaneous removal. In this study, magnetically recoverable La2O2CO3/Fe3O4 nanosheets were synthesized through the calcination of La-Fe binary metal glycolate. Based on magnetic and adsorption properties, La2O2CO3/Fe3O4 nanosheets with a La to Fe molar ratio of 1:1 (La2O2CO3/Fe3O4-1) were selected for further exploration. Electron microscopy characterization revealed that the nanocomposites consist of stacked La2O2CO3 and Fe3O4 nanosheets. The La2O2CO3/Fe3O4-1 nanocomposites exhibited exceptional adsorption capacities of 114.6 mg P/g and 230.2 mg As/g. Additionally, the material exhibited rapid adsorption kinetics and maintained excellent adsorption performance within a pH range of 3.0 to 9.0, showing significant selectivity for phosphate and arsenate even in the presence of various coexisting ions. Adsorption-desorption cycling tests indicated good potential for recycling. When applied to the spring water of Yangzonghai Lake, the material efficiently reduced the concentrations of phosphate and arsenate from 0.725 mg P/L and 1.380 mg As/L to below 0.020 mg P/L and 0.010 mg As/L, respectively. Mechanistic studies suggest that La2O2CO3 facilitates the removal of phosphate and arsenate primarily through electrostatic attraction and ligand exchange. These findings indicate that La2O2CO3/Fe3O4 holds significant promise for the co-removal of phosphate and arsenate, even at low concentrations.

Chemical Vapor Deposition of Two-Dimensional Magnetite Nanosheets and Raman Study of Heat-Induced Oxidation Reaction

Two-dimensional magnetic materials exhibiting antiferromagnetic properties at room temperature offer significant potential for developing next generation spintronic nanodevices. This work presents controlled synthesis of two-dimensional magnetite (Fe3O4) nanosheets utilizing lost cost and convenient chemical vapor deposition (CVD) technique, Raman spectroscopy study of laser-heating and annealing induced oxidation reaction. X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and Raman spectroscopy characterizations demonstrated that Fe3O4 nanosheets down to about 10 nm with good crystalline quality, surface uniformity, and minimal defects can be obtained by optimizing the growth parameters in our CVD synthesis. Both laser-heating and annealing studies of Fe3O4 nanosheets indicated that ferrimagnetic Fe3O4 nanosheets gradually change to antiferromagnetic α-Fe2O3 nanosheets at about 400 °C. Our study showed that Raman spectroscopy provides a convenient and powerful method for estimating heat-induced temperature and investigating oxidation reaction.

Hierarchical Fe2O3 nanosheets anchored on CoMn layered double hydroxide nanowires for high-performance supercapacitor

The pursuit of enhanced energy storage efficiency has driven the development of hybrid electrode structures. Overcoming the limitations of single-component metal oxides regarding stability and ionic electron mobility, we have engineered a hybrid structure, CoMn-Fe/NF. This structure comprises vertically grown Fe2O3 nanosheets on CoMn layered doubled hydroxide (LDH) nanowires anchored on nickel foam (NF) via a hydrothermal synthesis method. This hybrid configuration demonstrated a remarkable specific capacitance of 2633F g−1 at 1 A/g, coupled with exceptional stability. When integrated into a supercapacitor device, it achieved a high energy density of 87.80 Wh kg−1 at a power density of 0.245 kW kg−1 while maintaining outstanding cycling performance. The interconnected network of nanowires and nanosheets in CoMn-Fe/NF facilitated ion mobility and provided abundant accessible active sites, resulting in robust electrochemical activity, low resistance, and enhanced supercapacitor performance. This study introduces an innovative strategy for synthesizing electrode materials with significant potential for high-performance hybrid supercapacitors, representing a substantial advancement in the development of efficient energy storage devices.

Fe2O3/ZnO heterojunction for efficient electrochemical nitrate reduction to ammonia.

Electrochemical nitrate reduction to ammonia (ENO3RR) has attracted great attention owing to its characteristics of treating wastewater while producing high value-added ammonia. In this study, we successfully prepared a heterojunction electrocatalyst Fe2O3/ZnO consisting of Fe2O3 nanosheets and ZnO nanoparticles, where the construction of the Fe2O3/ZnO heterojunction not only increased the exposure of the active sites of the catalyst, accelerated the interfacial electron transfer, and improved the conductivity of the catalyst but also optimized its overall electronic structure. Thus, Fe2O3/ZnO demonstrated a high Faraday efficiency of 97.4% and an ammonia yield of 6327.2 μg h-1 cm-2 at -1.0 V (vs. RHE) in 0.1 M KNO3 and 0.1 M PBS. DFT calculations also confirmed that the constructed Fe2O3/ZnO heterojunction effectively decreased the reaction energy barrier of *NO → *NHO and accelerated the reaction kinetics, which is favourable for ENO3RR. This study provides a new and facile design strategy of catalysts for electrochemical nitrate reduction to ammonia.

Effect of morphology on tribological properties of Fe3O4 as lubricant additive: Nanospheres, nanowires and nanosheets

This work investigates the morphologies of Fe3O4 nanoparticles how to affect the tribological properties when they are applied as nano-lubricating additives. Fe3O4 nanoparticles with different morphologies (nanospheres, nanowires and nanosheets) are synthesized by solvothermal method and added in liquid paraffin to test the tribological properties. Although Fe3O4 nanoparticles can achieve certain anti-friction and anti-wear effects under the same conditions, the Fe3O4 nanospheres shows the best tribological properties. In the optimal concentrations of Fe3O4 nanospheres, nanowires and nanosheets, the changes of the average friction coefficient are almost the same, the wear volume are decreased by 91.03%, 86.88% and 87.63%, respectively. Fe3O4 nanoparticles with different morphologies can form films in the gap between friction pairs when they are used as additives, which ensures that three different Fe3O4 nanoparticles can enhance the tribological properties of the liquid paraffin. Compared with Fe3O4 nanowires and nanosheets, besides the tribological films, Fe3O4 nanospheres play roles in self-healing and rolling friction effects between friction pairs, resulting in the best anti-friction and anti-wear.

Defect-rich hierarchical porous spinel MFe2O4 (M = Ni, Co, Fe, Mn) as high-performance anode for lithium ion batteries

Exploring innovative anode materials with excellent lithium storage capability is an urgent and challenging task. Among various candidates, the spinel ferrites based anodes received huge attention owing to the high theoretical capacity. However, the rapid capacity decaying and sluggish reaction kinetics during cycling have severely hampered their commercialization process. Herein, the hierarchical porous spinel MFe2O4 (M = Ni, Co, Mn, Fe), comprised of Mn doped porous NiFe2O4/CoFe2O4 heterostructure ligament network and Ni/Co/Mn co-doped Fe3O4 nanosheets network, is synthesized through a facile chemical dealloying strategy. The as-prepared MFe2O4 anode shows impressive cycling stability, revealing a discharge capacity of 1161.6 mAh g−1 after cycling for 1500 cycles at 500 mA g−1. Furthermore, the assembled LiFePO4//MFe2O4 full cell can display a reversible capacity of 111.2 mAh g−1 at 0.5 C after 150 cycles, exhibiting the great potential of the practical application of the MFe2O4 in the next-generation LIBs. The remarkable Li storage properties can be attributed to the particular hierarchical porous structure, highly active NiFe2O4/CoFe2O4 heterointerface and abundant surficial oxygen defects, high stable spinel structure contributed from high conformational entropy of polymetallic ions, and a double role of Mn doping in the cycling process. The structure regulating strategy proposed here is greatly expected to boost the developing of high-performance spinel ferrites based anodes.

Rational Design of High-Performance Electrodes Based on Ferric Oxide Nanosheets Deposited on Reduced Graphene Oxide for Advanced Hybrid Supercapacitors.

The core strategy for constructing ultra-high-performance hybrid supercapacitors is the design of reasonable and effective electrode materials. Herein, a facile solvothermal-calcination strategy is developed to deposit the phosphate-functionalized Fe2O3 (P-Fe2O3) nanosheets on the reduced graphene oxide (rGO) framework. Benefiting from the superior conductivity of rGO and the high conductivity and fast charge storage dynamics of phosphate ions, the synthesized P-Fe2O3/rGO anode exhibits remarkable electrochemical performance with a high capacitance of 586.6Fg-1 at 1Ag-1 and only 4.0% capacitance loss within 10000 cycles. In addition, the FeMoO4/Fe2O3/rGO nanosheets are fabricated by utilizing Fe2O3/rGO as the precursor. The introduction of molybdates successfully constructs open ion channels between rGO layers and provides abundant active sites, enabling the excellent electrochemical features of FeMoO4/Fe2O3/rGO cathode with a splendid capacity of 475.4C g-1 at 1Ag-1. By matching P-Fe2O3/rGO with FeMoO4/Fe2O3/rGO, the constructed hybrid supercapacitor presents an admirable energy density of 82.0Whkg-1 and an extremely long working life of 95.0% after 20000 cycles. Furthermore, the continuous operation of the red light-emitting diode for up to 30min demonstrates the excellent energy storage properties of FeMoO4/Fe2O3/rGO//P-Fe2O3/rGO, which provides multiple possibilities for the follow-up energy storage applications of the iron-based composites.

Fe2O3 nanosheet sacrificed templates for highly-permeable hollow fiber ultrafiltration membranes

Hollow fiber membranes (HFMs) have been widely used in ultrafiltration. However, current HFMs usually exhibit low permeance to ensure satisfactory retention performances. Blending nanomaterials into HFMs matrix can enhance permeance but still can be improved. Herein, we report a facile strategy to fabricate highly-permeable HFMs using inorganic metal oxide nanoparticles as sacrificed templates. Ultrathin Fe2O3 nanosheets are synthesized via hydrothermal method. After blending with minuscule concentrations (0.4 % mass fraction) of the nanosheets, spinning and acid dissolving, HFMs are fabricated with nanosheet-templated channels. These HFMs have enhanced porosity (from 49.7 % to 86.9 %), pore size (from 12.5 nm to 27.5 nm), roughness (from 16.0 nm to 29.3 nm), hydrophilicity (water contact angle from 93.7° to 77.8°), mechanical properties (tensile strength from 3.0 MPa to 4.2 MPa), and antifouling ability (flux recovery ratio from 0.58 to 0.71). The permeance can be increased significantly to 209.2 L m−2 h−1 bar−1, a 10.6-fold improvement compared to the unblended HFMs. The solute rejection of the HFMs is not compromised (e.g., maintaining 10 nm Au at 96.3 % and bovine serum albumin at 86.2 %) due to the small size of templated channels. The sacrificed template blending strategy can be applied to other inorganic metal nanoparticles and various polymer-based HFMs. This work can also provide great inspiration for flexibly designing and conveniently fabricating highly-permeable HFMs in industrial ultrafiltration.

Self-supported iridium integrated leaf-shaped Fe3O4 columnar arrays toward highly efficient oxygen evolution at industrial-grade current density

The sluggish kinetics for oxygen evolution reaction (OER) significantly impede the practical applications of electrocatalytic water splitting technology for renewable energy source. The facile design of self-supporting electrocatalysts with high activity and stability for OER catalysis at industrial-grade current density is of paramount significance to mitigate the above bottlenecks. We report herein the construction of iron foam (IF) self-supported Ir-magnetite (Ir-Fe3O4/IF-T-x) electrode via galvanic replacement between IrCl62− ions and Fe2+ in Fe3O4 nanosheet arrays, which is simply synthesized by annealing IF in air and subsequent thermal treatment in reducing atmosphere. Such pre-treatment enables the growth of leaf-like Fe3O4 nanosheet arrays with rich Fe2+ species and oxygen defects, which facilitate the depositing of Ir on the surface of nanosheet arrays and thereby promote the electrochemical OER performance in basic electrolyte. Impressively, the optimized Ir-Fe3O4/IF-400-2 delivers the highest electrocatalytic activity with a low overpotential of 316 mV to obtain industrial-grade current density of 500 mA cm−2 for alkaline OER. Meanwhile, the catalyst still shows good long-term stability after 36 h V-t test at 100 mA cm−2. This study offers a simple and efficient pathway to prepare self-supporting electrode for alkaline OER at industrial-grade current density.

Controllable Synthesis, Photocatalytic Property, and Mechanism of a Novel POM-Based Direct Z-Scheme Nano-Heterojunction α-Fe2O3/P2Mo18.

In order to improve photocatalytic activity and maximize solar energy use, a new composite material Fe2O3/P2Mo18 was prepared by combining polyoxometalates (P2Mo18) with Fe2O3 nanosheets. FT-IR, XRD, XPS, SEM, TEM, UV-vis, EIS, and PL were used to characterize the composite material, and nano-Fe2O3 of different sizes and morphologies with a controllable absorption range was prepared by adjusting the reaction time, and, when combined with P2Mo18, a composite photocatalyst with efficient visible light response and photocatalytic activity was constructed. The EIS, Bode, and PL spectra analysis results show that the Fe2O3/P2Mo18 composite material has outstanding interfacial charge transfer efficiency and potential photocatalytic application possibilities. Model reactions of methylene blue (MB) and Cr (VI) photodegradation were used to evaluate the redox activity of Fe2O3/P2Mo18 composites under simulated visible light. The photocatalytic degradation rate was as high as 98.98% for MB and 96.86% for Cr (VI) when the composite ratio was Fe2O3/P2Mo18-5%. This research opens up a new avenue for the development of high-performance photocatalysts.

Engineering a synergistic CoMn-LDH/Fe2O3@NF heterostructure for highly efficient oxygen evolution reaction

The pursuit of low-cost, highly efficient energy materials remains a key challenge in clean energy technology. This study introduces a hybrid heterostructure, CoMn-LDH/Fe2O3@NF, comprising Fe2O3 nanosheets coated on CoMn nanowires (NWs) grown on nickel foam (NF). Notably, the heterostructure exhibits exceptional performance in the oxygen evolution reaction (OER), with remarkably low overpotentials (η) of 191 mV and 368 mV, yielding current densities (j) of 10 mA cm−2 and 500 mA cm−2, respectively. Moreover, when coupled with an efficient hydrogen evolution reaction catalyst, CoMn-LDH/Fe2O3@NF achieves j of 10 mA cm−2 and 500 mA cm−2 in overall water splitting at impressively low cell voltages of 1.48 V and 1.82 V, respectively. These exceptional advancements are attributed to the presence of electrochemically accessible active sites, rapid electron transport, and a strong synergistic effect between the Fe2O3 nanosheets and CoMn-LDH NWs. This innovative hybrid heterostructure design holds tremendous potential for advancing next-generation OER catalysts, effectively addressing the demand for cost-effective and highly efficient materials. Significantly, this study contributes to advancing sustainable and viable energy technologies.

Nanosheet arrays of iron oxide for enhanced ammonia synthesis via electrochemical nitrogen reduction for prospective algal membrane bioreactors

The earth's nitrogen cycle relies on the effective conversion of nitrogen (N2) to ammonia (NH3). As a result, the research and development of catalysts that are earth-abundant, inexpensive, and highly efficient but do not need precious metals is of the utmost significance. In this investigation, we present a controlled synthesis technique to the fabrication of an iron oxide (Fe2O3) nanosheet array by annealing at temperatures ranging from 350 to 550 °C. This array will be used for the electrochemical reduction of atmospheric N2 to NH3 in electrolytes. The Fe2O3 nanosheet array that was produced as a result displays outstanding electrochemical performance as well as remarkable stability. When compared to a hydrogen electrode working under normal temperature and pressure conditions, the Fe2O3 nanosheet array produces an impressive NH3 production rate of 18.04 g per hour per mg of catalytically active material in 0.1 M KOH electrolyte, exhibiting an enhanced Faradaic efficiency (FE) of 13.5% at −0.35 V. This is accomplished by exhibiting an enhanced Faradaic efficiency (FE) of 0.1 M KOH electrolyte. The results of experiments and electrochemical studies reveal that the existence of cation defects in the Fe2O3 nanosheets plays an essential part in the enhancement of the electrocatalytic activity that takes place during nitrogen reduction reactions (NRR). This study not only contributes to the expanding family of transition-metal-based catalysts with increased electrocatalytic activity for NRR, but it also represents a substantial breakthrough in the design of catalysts that are based on transition metals, so it's a win-win. In addition, the use of Fe2O3 nanosheets as electrocatalysts has a lot of potential in algal membrane bioreactors because it makes nitrogen fixation easier, it encourages algae growth, and it makes nitrogen cycling more resource-efficient.

Insights into the selectivity of metallic oxides for arsenic and phosphate from EXAFS and DFT calculations

Phosphate is the biggest competitor for arsenic removal. Nanoscale metal oxides (NMOs) are commonly used to treat arsenic-contaminated water, yet their selective adsorption mechanisms for arsenic and phosphate are poorly understood. We quantified the selectivity of iron oxide (Fe2O3), zinc oxide (ZnO), and titanium dioxide (TiO2) nanosheets for arsenic in systems containing arsenic and phosphate, and determined the interaction of phosphate and arsenate/arsenite on metal oxide surfaces through batch experiments, spectroscopic techniques, and DFT calculations. We found that Fe2O3, TiO2, and ZnO nanosheets exhibit selectivity for arsenate/arsenite in the presence of phosphate, with Fe2O3 the most selective, followed by TiO2 and ZnO. The bonding mechanism on these metallic oxide surfaces dominates the selectivity. The more stable inner-sphere complexes of arsenate on the surfaces of Fe2O3 (bidentate binuclear), TiO2 (bidentate binuclear), and ZnO nanosheets (tridentate trinuclear) contribute to their preference for arsenate over phosphate. This difference in arsenate selectivity can be reflected in the difference in adsorption energy, net electron transfer number, and M − O bond length of the most stable inner sphere complexes. Overall, our study elucidated the selective adsorption mechanisms of arsenate/arsenite on Fe2O3, TiO2, and ZnO surfaces and highlighted the need to consider the competition between arsenate and phosphate during their removal from contaminated water.