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Graphical abstract Highlights • Very highly dispersed Pt-based catalysts were prepared by the SEA method. • Pt particles were preferentially deposited over the MOx surface. • Strong metal-support interactions existed between Pt and MO x species. • Pt/MO x /TiO 2 catalysts synthesized by SEA were evaluated during CO oxidation in presence of excess hydrogen. • A higher calcination temperature can improve the catalytic behavior of Pt/MO x /TiO 2 for the PROX reaction. Abstract In this work, the catalytic properties of Pt/MO x /TiO 2 (M = Fe, Co) catalysts prepared by strong electrostatic adsorption (SEA), were investigated for the preferential oxidation (PROX) of CO in H 2. The SEA method was chosen to achieve a preferential adsorption of Pt onto supported MO x nanoparticles rather than onto the TiO 2 surface. XPS, TPR and TEM analysis indicate that the enhancement in the catalytic activity of Pt/MO x /TiO 2 is related to a synergetic effect originated by a close contact between Pt and MO x (M = Fe, Co) surface. The results clearly show that Pt supported on CoO x /TiO 2 calcined at 300 °C, and then reduced at 100 °C, exhibits the highest activity, e.g. higher CO conversion and CO 2 selectivity, among the supported catalysts studied in this work, that was attributed to a higher concentration of Pt-CoO x moieties over the catalytic surface. This study reports a simple and efficient way to synthesize Pt-promoted catalysts where strong metal-support interactions are highly desired to improve the catalytic performance of selective oxidation reactions. [ABSTRACT FROM AUTHOR]

Abstract In coastal environments, oscillating redox conditions represent a functional state affecting organic matter mineralization. Such transient diagenetic processes remain difficult to study in situ, and we therefore designed a specific reactor to provide experimental results that are environmentally relevant in this context. Here, we present the results of two independent experiments carried out with sediment having contrasting Fe, Mn contents, collected from a coastal tidal lagoon (the Arcachon bay) and a mesotidal estuary (Adour river). Sediment and overlying water were mixed to form slurries that were submitted to redox oscillations to assess the diagenetic mechanisms that affect N, P, Fe, Mn, and S. Changing from anoxic to oxic conditions, we observed a rapid oxidation of dissolved Fe(II) and dissolved inorganic phosphorus (DIP) was apparently trapped by the newly formed Fe-oxyhydroxides (Fe-ox). DIP was totally titrated in the coastal lagoon sediment, but not in estuarine sediment, where the initial amount of Fe available was lower. In both experiments, Mn(II) was only slowly oxidized during the oxidation events and a major part of Mn(II) was adsorbed on new Fe-ox. In coastal lagoon sediment, ammonium remained constant in oxic conditions while nitrate was produced from organic-N mineralization. On the contrary, in estuarine sediment, ammonium was quantitatively oxidized to nitrate. When the conditions became anoxic again, direct reduction of nitrate to ammonium occurred in coastal lagoon sediment. Anaerobic production of nitrate occurred in estuarine sediment, probably because Mn-oxides (Mn-ox), which had a high concentration, acted as an oxidant for ammonium. Consequently, nitrate production prevented Fe(II) accumulation. The Mn-N-Fe coupling outlined here is an apparent indirect oxidation of Fe(II) by Mn-ox through anaerobic nitrification (with Mn-ox) and denitrification (with Fe-ox). This coupling also implied P availability because of the strong control of P by Fe. These experimental results show that nutrient dynamics in oscillatory redox environments such as the estuarine turbidity zone, bioturbated sediment, or tidal permeable sediments highly depends on Mn-and Fe-ox availability. Highlights • We designed a reactor to simulate oscillating redox conditions. • Two sediments with different Mn oxide content submitted to redox oscillations. • Nutrient dynamics depends on reactive Fe and Mn content. • We outline a Mn-N-Fe coupling, which also imply P availability. • Anaerobic nitrification with Mn-ox and denitrification with Fe-ox. [ABSTRACT FROM AUTHOR]

Abstract The current study scrutinized a two dimensional CVFEM modeling for convective flow inside a cylindrical enclosure with elliptical heat fluxes. This article deals with H 2 O-based iron oxide nanoparticles. Ferrofluid transportation was denoted with Navier–Stokes equations in which porous medium were treated according to non-Darcy formulation. Also, entropy generation has been calculated. Computations were examined over a range of relevant variables: Hartmann, Rayleigh and Darcy numbers. Results indicate that to reduce energy consumption, permeability should be increased. Second law results demonstrate that the part of the entropy due to each factors changes as active parameters change. Highlights • Exergy loss and thermal behavior of ferrofluid have been investigated. • CVFEM is used to model MHD flow in a porous media. • Hartmann number has direct relationship with exergy loss. • Bejan number increases by Da and Ra. [ABSTRACT FROM AUTHOR]

Highlights • Hydrothermal syntheses of Vanadium doped α - F e 2 O 3 cubic particles with enhanced photoelectrochemical activity was proposed in this work. • Vanadium doping effect the photoelectrical properties of the α - F e 2 O 3 cubic particles. • With increase in concentration of Vanadium optical properties also changes. • PEC analysis shows that density of current increases 16 time for 3 % V - d o p e d - α - F e 2 O 3. Abstract Water splitting to produce hydrogen using semiconductor material has been a focus of intense research in last few years. The main challenge to accomplish this task is to find a suitable band gap, non-toxic and earth abundant material for photoelectrochemical (PEC) process. α - F e 2 O 3 is proven to be a suitable candidate for PEC process because of its stability, non-toxic nature, abundance is nature and a narrow band gap of (1.9–2.2 eV). In this work V-doped α - F e 2 O 3 cubic particles were deposited on ITO substrate by hydrothermal and annealing method. The composition of V was controlled in bath solution by changing the concentration of V from 0 to 3%. After successful deposition, all samples were characterized by structural studies using x-ray diffraction, morphological studies using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), optical studies using UV–VIS spectroscopy to measure band gap (eV) and chronoamperometry was applied to measure photo response of samples. SEM and TEM studies revealed cubic particles with size varying from 350 nm to 400 nm. XRD studies confirms hematite structure for V-doped and undoped α - F e 2 O 3 samples. Optical studies show a variation of band gap from 1.89 eV ∼ 2.09 eV. Chronoamperometry studies revealed that 3%V-doped samples displayed 16 times higher PEC activity with respect to undoped α - F e 2 O 3 film. The higher current density can be attributed to band gap narrowing and increased donor density. Result provided in this work can provide an imperative guideline for the design of efficient photocatalysis application using α - F e 2 O 3. [ABSTRACT FROM AUTHOR]

Abstract It is reported the magnetic coating structure has a significant influence on their microwave absorption performance (MAP) for nano-Fe 3 O 4 -coated CNT. However, it is still uncertain which type of coating structure is favorable for Fe 3 O 4 -coated reduced graphene oxides (rGO) to enhance the MAP. In this work, nano-Fe 3 O 4 compact-coated rGO (FCG) and Fe 3 O 4 loose-coated rGO (FLG) are prepared firstly and their MAP have been investigated. A strong coating structure dependent effect is found and the FCG is proved to own much better MAP than FLG. Afterwards, the nano-Fe 3 O 4 compact-coated CNT and rGO mixture (FCCG) are fabricated. It is shown that the MAP could reach as low as −42.9 dB, and the high coverage density of Fe 3 O 4 nanoparticles plays important role on achieving this excellent property. Furthermore, in order to investigate the synergistic effects between CNT and rGO, FCCG with different mass ratios of CNT to rGO have been synthesized and optimized to maximize the effective complementarities between the dielectric loss and the magnetic loss to obtain high MAP. Results show the FCCG with 50 wt% rGO content achieves the best MAP, which can be attributed to the promoted consequent dielectric relaxation process and the magnetic loss induced by the increased multiple interface. Graphical abstract Composite with excellent MAP has been obtained guided by the proposed coating structure-property relationship for nano Fe 3 O 4 coated carbon-based materials. Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Hematite (α -Fe 2 O 3) is one of the most widely studied materials for the application of water oxidation in the field of renewable energy. In order to push hematite toward maximal efficiency, a better understanding of the intrinsic limitations is essential. In this review, we cover our latest results on identifying and finding ways to overcome bottlenecks by modelling the electrochemical processes in hematite at three regimes: 1. at the bulk, the calculated hole effective mass is unfavorably high and conductivity can be improved through doping and alloying, 2. at the surface, catalysis is slow and involves long-lived surface states, but the catalytic overpotential can be reduced by adding a doping gradient or overlayers without strain, and 3. at the back contact the losses can be improved by selecting a proper metal contact. We provide unique analysis approaches that reveal fundamental understanding of electrochemistry with hematite. These models have made an impact on understanding experimental observations and have influenced subsequent theoretical investigations. [ABSTRACT FROM AUTHOR]

The importance of atherosclerosis is driving research to create improved diagnostic tools based on molecular imaging. Pretargeted imaging is the use of bioorthogonal probes that selectively accumulate upon reaction with a pre-modified biomolecule in vivo. To date, this very promising approach has not been applied to atherosclerosis. Neither has been the use of a single nano-radiomaterial for PET / T 1 -MR imaging of atherosclerosis. Here, we synthesized bioorthogonal nano-radiomaterials for in vivo pretargeted molecular imaging in a mouse model of atherosclerosis. Based on tetrazine-ligation, these functionalized 68Ga iron oxide nano-radiomaterials provide simultaneous PET and T 1 -MRI signals and selectively accumulate in atherosclerotic plaques in mice sequentially injected with trans-cyclooctene-modified antibodies against oxidized LDL followed by the hybrid nano-radiomaterial. Our results demonstrate the ability of this approach to unambiguously detect atherosclerosis. Furthermore, we show the first example of how hybrid imaging can be used for pretargeted bioorthogonal molecular imaging with nanomaterials. Unambiguous detection of atherosclerosis by the in vivo reaction of 68Ga iron oxide nanoparticles with anti-oxidized phospholipids antibody. Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Despite the advances in molecularly targeted therapies, delivery across the blood-brain barrier (BBB) and the targeting of brain tumors remains a challenge. Like brain, bone is a common site of metastasis and requires therapies capable of discerning the tumor from its healthy cellular milieu. To tackle these challenges, we made a variation on the previously proposed concept of the earthicle and fabricated an aqueous, surfactant-free ferrofluid containing superparamagnetic iron oxide nanoparticles (SPIONs) coated with silicate mesolayers and carbon shells, having 13 nm in size on average. Nanoparticles were synthesized hydrothermally and characterized using a range of spectroscopic, diffractometric, hydrodynamic and electron microscopy techniques. The double coating on SPIONs affected a number of physicochemical and biological properties, including colloidal stability and cancer targeting efficacy. Nanoparticles decreased the viability of glioblastoma and osteosarcoma cells and tumors more than that of their primary and non-transformed analogues. They showed a greater preference for cancer cells because of a higher rate of uptake by these cells and a pronounced adherence to cancer cell membrane. Even in an ultralow alternate magnetic field, nanoparticles generated sufficient heat to cause tumor death. Nanoparticles in MDCK-MDR1 BBB model caused mislocalization of claudin-1 at the tight junctions, underexpression of ZO-1 and no effect on occludin-1 and transepithelial resistance. Nanoparticles were detected in the basolateral compartments and examination of LAMP1 demonstrated that nanoparticles escaped the lysosome, traversed the BBB transcellularly and localized to the optic lobes of the third instar larval brains of Drosophila melanogaster. The passage was noninvasive and caused no adverse systemic effects to the animals. In conclusion, these nanoparticulate ferrofluids preferentially bind to cancer cells and, hence, exhibit a greater toxicity in these cells compared to the primary cells. They are also effective against solid tumors in vitro , can cross the BBB in Drosophila, and are nontoxic based on the developmental studies of flies raised in ferrofluid-infused media. Statement of Significance We demonstrate that a novel, hydrothermally synthesized composite nanoparticle-based ferrofluid is effective in reducing the viability of osteosarcoma and glioblastoma cells in vitro , while having minimal effects on primary cell lines. In 3D tumor spheroids, nanoparticles greatly reduced the metastatic migration of cancer cells, while the tumor viability was reduced compared to the control group by applying magnetic hyperthermia to nanoparticle-treated spheroids. Both in vitro and in vivo models of the blood-brain barrier evidence the ability of nanoparticles to cross the barrier and localize to the brain tissue. These composite nanoparticles show great promise as an anticancer biomaterial for the treatment of different types of cancer and may serve as an alternative or addendum to traditional chemotherapies. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Iron oxide nanowires are fabricated by PLD in the presence of magnetic field. • The ambient gas and its pressure strongly influence the nanowires characteristics. • Nanowires produced in open air are aligned along the magnetic field lines. • The density of the nanowires decreases with the increase of the target-substrate distance. • The nanowires show hysteresis with values of the coercive field of ∼500 Oe at 5 K. Abstract This paper presents an experimental investigation on laser-assisted fabrication of oriented nanowires composed by magnetic nanoparticles. The nanowires were produced by implementation of pulsed laser deposition in presence of a magnetic field. The application of an external magnetic field led to the formation of nanowires with a length of several micrometers whose orientation is influenced by the direction of the magnetic field lines. The influence of the type of ambient gas and its pressure on morphology and phase composition of the deposited samples was investigated. It was found that the ambient gas has direct influence on both the degree of orientation and the phase composition of the nanowires. SEM analysis of samples deposited at different target-substrate distances showed that the density of the nanowires decreases with the increase of the distance. A preliminary result on the magnetic properties of the produced nanowires is also reported. [ABSTRACT FROM AUTHOR]

Abstract CeO 2 -supported Fe 2 O 3 is a satisfactory oxygen carrier for chemical looping hydrogen generation (CLHG). However, the sintering problem restrains its further improvement on redox reactivity and stability. In the present work, a core-shell-structured Fe 2 O 3 /CeO 2 (labeled Fe 2 O 3 @CeO 2) oxygen carrier prepared by the sol-gel method was studied in a fixed bed. The effect of the core-shell structure on the sintering resistance and redox performance was investigated with a homogenous composite sample of Fe 2 O 3 /CeO 2 as a reference. The results showed that the Fe 2 O 3 @CeO 2 exhibited much higher redox reactivity and stability than the Fe 2 O 3 /CeO 2 with no CO or CO 2 observed in the generated hydrogen, while the hydrogen yield for Fe 2 O 3 /CeO 2 decreased with redox cycles due to serious sintering. The satisfactory performance of Fe 2 O 3 @CeO 2 can be ascribed to its high sintering resistance, since the core-shell structure suppressed the outward migration of Fe cations from the bulk to the surface of the particles. On the other hand, the migration of Fe cations and their subsequent enrichment on the particle surface led to the serious sintering of Fe 2 O 3 /CeO 2. The crystallite size evolution of Fe 2 O 3 and CeO 2 in redox cycles further demonstrated the higher sintering resistance of Fe 2 O 3 @CeO 2. Further, the particle size distribution (PSD) results indicated the agglomeration of Fe 2 O 3 /CeO 2 after cycles. In addition, the CeO 2 shell could facilitate the transport of oxygen ions between the iron oxide nanoparticle core and the shell surface. Therefore, the coating of nanoscale Fe 2 O 3 with a CeO 2 shell did not reduce the redox reactivity and stability of Fe 2 O 3 @CeO 2 , but rather promoted it, though less oxygen-ionic-conductive CeFeO 3 was generated. Graphical abstract Image 1 Highlights • A core-shell structured Fe 2 O 3 @CeO 2 prepared by sol-gel method was studied for CLHG. • Fe 2 O 3 @CeO 2 exhibited significantly enhanced sintering resistance. • Fe 2 O 3 @CeO 2 showed much higher activity and stability than the composite Fe 2 O 3 /CeO 2. • Fe 2 O 3 @CeO 2 prevented the outward migration of Fe cations from the bulk to surface. • CeO 2 shell facilitated oxygen mobility between the Fe 2 O 3 core and the shell surface. [ABSTRACT FROM AUTHOR]

Abstract Phase changes of natural hematite are often practiced to improve heavy metal removal and magnetism for easy recycling. In this work, pinewood biomass (PB) and natural hematite (H) admixtures were pyrolyzed at 300, 450 and 600 °C under N 2 environment to prepare HBC nanocomposites (HBC300, HBC450 and HBC600). The X-ray diffraction (XRD) confirmed the reductive transformation of hematite (crystallite size ≈ 47 nm) into magnetite (25 nm) and further to wustite (25 nm) and zerovalent iron (48 nm). The Langmuir isotherms showed that the maximum sorption capacities of HBC300, HBC450, and HBC600 were 173, 138, and 130 mmol kg−1 for Cd2+, and 359, 172, and 197 mmol kg−1 for Cu2+, respectively. The higher pH up to 5 increased sorption of both Cd2+ and Cu2+, whereas the higher ionic strength (0.05–0.4 M) decreased Cd2+ sorption. Sorption of Cd2+ and Cu2+ by HBC300 was accompanied by one order of magnitude greater cation release than HBC450 and HBC600. In a binary system, Cd2+ sorption was depressed by over four times in presence of Cu2+. Overall, ion exchange was more pronounced for HBC300, and Cu2+ was more favorably retained by specific sorption than Cd2+. The greater magnetism of HBC nanoparticles favors separation from aqueous solutions. Graphical abstract Unlabelled Image Highlights • Pinewood facilitated transformation of natural hematite as α-Fe 2 O 3 → Fe 3 O 4 → FeO → Feo. • Crystallite size of Fe oxide dropped from 47 to 25 nm between 300 and 600 °C. • Cd2+ and Cu2+ sorption by biochar composites was over five times higher than pristine precursors. • Biochar composites prepared at 300 °C over 450 and 600 °C was more favorable for Cd2+ and Cu2+ removal. • Cu2+ was more preferentially retained by specific retention mechanisms. [ABSTRACT FROM AUTHOR]

Abstract Time-resolved x-ray imaging is used to capture high-resolution images of the Al/Fe 2 O 3 thermite reaction as it proceeds in an extended burn tube. The observed thermite reaction products are generally large, multi-phase composite particles. Image processing algorithms are developed to extract a continuous record of composite particle size as a function of time and distance from the ignition point. Small particles are observed immediately after ignition, followed by a rapid increase in particle size and a gradual decline toward late times. Correlating the dynamic particle size with visible light emission from the reaction, we propose a two-stage mechanism where the combination of early ignition and delayed expansion causes the material closest to the ignition point to undergo substantial coalescence before it begins moving down the tube. We also identify two mechanisms that may contribute to particle size refinement at late times, both based on the collapse of large gas bubbles that are observed preferentially in particles at earlier times. A new approach to extracting burn times from luminous intensity data is explored, and we find that a more nuanced analysis of burn time and luminous intensity may help to improve reactivity assessments when data from in situ studies is unavailable. [ABSTRACT FROM AUTHOR]

Abstract In this work, a hot-melt adhesive used by automotive industries for bonding plastic components has been modified with three different percentages of nanofiller (iron oxide) in order to make the adhesive electromagnetically sensitive and to perform adhesive joint separations. Fe 3 O 4 particles with a weight concentration of 3%, 5% and 10% were embedded in the adhesive matrix. Single Lap Joint (SLJ) tests showed that a slight increase of the maximum load and a more ductile behaviour are obtained. The sensitivity of these modified adhesive performance to the induction heating process was studied with respect to some relevant parameters: the current (or power), the frequency of the electromagnetic induction field and the shape of the coil. Furthermore, the diameter of the hollow copper coil was modified in order to understand whether the coil temperature has an effect on the separation time. The separation time, that is an index of the time needed to reach the melt of the adhesive and the consequent SLJ separation, together with the temperature profile of the adhesives have been used to evaluate the sensitivity of these adhesives to the process parameters. The analysis on the temperature and separation time showed that the most influencing parameter is the frequency of the electromagnetic induction field. As expected, also the shape of the coil influences the separation time, in particular, the adhesive joint separated with the pancake coil showed lower values of the separation time compared to the solenoidal coils. Scanning Electron Microscope (SEM) showed that iron oxide particles tend to form small agglomerate that resulted well dispersed in the adhesive matrix. Thermogravimetric analysis (TGA) was used to verify that the separation procedure do not degrades these modified adhesives. [ABSTRACT FROM AUTHOR]

Highlights • Impact of differently modified dextran coated nanoparticles on HEWL fibrillization. • Nanoparticles inhibit formation of HEWL fibrils in concentration-dependent manner. • Size of nanoparticles influenced the extent of their inhibitory properties. • The highest inhibitory effect was observed for the smallest CMdex NPs. • Dextran coated nanoparticles are not toxic at concentration close to IC 50 values. Abstract More than 50 diseases are associated with a conversion of proteins or peptides from their soluble functional states to highly organized fibrillar aggregates called amyloid fibrils. Due to the specific physico-chemical properties, specifically designed iron oxide nanoparticles may be an effective strategy for inhibiting the amyloid fibrillization of proteins. The inhibitory effect of three types of iron oxide nanoparticles coated with differently modified dextran on lysozyme fibrils formation was studied by Thioflavin T assay and atomic force microscopy. The size and zeta potential of studied nanoparticles were determined by dynamic light scattering. It had been found that nanoparticles are able to inhibit formation of lysozyme amyloid aggregates in concentration-dependent manner. Our results suggest that size of nanoparticles influenced the extent of their inhibitory properties. Moreover, the most effective nanoparticles were not toxic after 48 h incubation with neuroblastoma SH-SY5Y cell line at concentration close to IC 50 values. [ABSTRACT FROM AUTHOR]

Abstract Composites of antimony metal, iron oxide, and carbon black are attractive for use as lithium ion battery anodes when high rate charging is required. The large capacity of such a composite, together with a voltage that is intermediate between lithium titanate and graphite, makes it possible to address the typical trade-off between high energy density and safe operation in high power conditions. In this work, a variety of mechanical homogenization processes are investigated. A minimum threshold of energy input per unit mass during milling is required to produce a sufficiently homogeneous microstructure, which is required for stable electrochemical performance. The surface area of the processed material is found to be a useful method for quantifying the degree of homogeneity in the composite and is well correlated to the electrochemical performance. This understanding enables simplified scaling on larger volume manufacturing assets. Graphical abstract Image 1 Highlights • An anode is made from a composite of antimony, iron oxide, and carbon. • Increased homogeneity creates longer cycle lifetimes in an electrochemical cell. • A minimum threshold of energy per unit mass during milling is required. • The BET surface area is inversely related to the cycling stability for this composite. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Magnetic nanomaterials were formed by pulsed laser ablation of iron in water and air. • Material ablated in water contained spherical particles of Fe 3 O 4 , Fe 2 O 3 , FeO and Fe. • Material ablated in air contained more Fe 3 O 4 and nitrogen (N-O, N-H or FeN x) • The surface composition and electrokinetic properties of the materials differed. • Material obtained in air is more stable in colloids due to its surface composition. Abstract Magnetic nanomaterials were synthesized using a method of pulsed laser ablation of an iron target in water (PLAL) and in air (PLAG). The microstructure and composition of the obtained materials differed. Spherical nanoparticles (NPs) of 2–80 nm containing Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , FeO and Fe were obtained using PLAL. According to the XPS and FTIR data, the surfaces of these particles contained both Fe 3 O 4 and Fe 2 O 3. PLAG led to the formation of NPs of 2–120 nm and 2-D lamellar structures up to 1 μm. This material contained more magnetite and nitrogen species, presumably iron nitrides. This material's surface contained FeOOH; the OH-group content was very high. It exhibited the greatest sedimentation stability and zeta potential value, while magnetic NPs (MNPs) obtained in water were less stable in colloids. The difference in the magnetic parameters of the two materials can be connected to not only the different composition (different magnetite content and nitrogen species presence) but also their structural features. Thus, PLAL and PLAG methods allowed for obtaining magnetic nanostructured materials with different characteristics suitable for application in different fields. [ABSTRACT FROM AUTHOR]

Abstract Associations with minerals can potentially augment soil organic carbon (SOC) stability by reducing the bioavailability and degradation of SOC. However, few studies have directly measured aerobic respiration of mineral-bound SOC. In this study, we investigated the microbial aerobic respiration and bioavailability of ferrihydrite-sorbed glucose (Fh-GLU) and ferrihydrite-sorbed formic acid (Fh-FA) by adding 13C-labeled compounds to a soil. During an 11-day incubation, 30.2% of free, non-Fh-sorbed glucose (GLU) and 61.8% of free formic acid (FA) were respired, whereas 4.2% and 27.9% of Fh-GLU and Fh-FA were respired, respectively. Our results demonstrated that Fh-bound GLU/FA had lower bioavailability compared to free organic compounds. Associations with Fh led to greater inhibition in the bioavailability of GLU than that for FA. The priming effects of added compounds on the respiration of native SOC were decreased by their association with Fh. Our results demonstrated that the bioavailability and priming effect of organic compounds depend on their interactions with minerals. Graphical abstract Graphical presentation illustrating the impact of mineral-SOC association on C preservation. Unlabelled Image Highlights • Sorption onto ferrihydrite decreased the bioavailability of glucose and formic acid. • Priming effects of organic carbon were inhibited by associations with ferrihydrite. • Reduction in bioavailability/priming effects of glucose was higher than formic acid. • Ferrihydrite sorbed more glucose than formic acid, driven by entropy change. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The engineering of iron oxide nanoparticles (IONPs) for biomedical use has received great interest over the past decade. In the present study we investigated the biocompatibility of IONPs grafted with linear (2P) or generation 1 (2PG1) or 2 (2PG2) dendronized oligoethyleneglycol units in THP-1-derived macrophages. To evaluate IONP effects on cell functionality and homeostasis, mitochondrial function (MTT assay), membrane permeability (LDH release), inflammation (IL-8), oxidative stress (reduced glutathione, GSH), NLRP3 inflammasome activation (IL-1β) and nanoparticle cellular uptake (intracellular iron content) were quantified after a 4-h or 24-h cell exposure to increasing IONP concentrations (0–300 µg Fe/mL). IONPs coated with a linear molecule, NP10COP@2P, were highly taken up by cells and induced significant dose-dependent IL-8 release, oxidative stress and NLRP3 inflammasome activation. In comparison, IONPs coated with dendrons of generation 1 (NP10COP@2PG1) and 2 (NP10COP@2PG2) exhibited better biocompatibility. Effect of the dendritic architecture of the surface coating was investigated in a kinetic experiment involving cell short-term exposure (30 min or 1 h 30) to the two dendronized IONPs. NP10COP@2PG2 disrupted cellular homeostasis (LDH release, IL-1β and IL-8 secretion) to a greater extend than NP10COP@2PG1, which makes this last IONP the best candidate as MRI contrast or theranostic agent. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fe 2 O 3 nanoparticles were embedded into hypercrosslinked porous polymeric matrix. • An increase in the content of Fe 2 O 3 nanoparticles reduced the specific surface area. • 7%Fe 2 O 3 -Porolas prepared using iron oxalate showed high adsorption capacity. • Almost complete decolorization of MB (96–98%) and >97% TOC were achieved. • Inexpensive and efficient Fe 2 O 3 -Porolas composite can be used in water treatment. Abstract The use of polymer sorbents in wastewater treatment can generate large-scale secondary waste due to the oxidation of the polymer matrix, stemming from the ionogenic functional groups or impurities. In this work, amorphous Fe 2 O 3 nanoparticles were embedded into a porous non-ionogenic polymer matrix (Porolas) using two different Fe(III) salts (iron nitrate and iron oxalate) for designing an easily separable and recyclable photocatalytic system. The Fe 2 O 3 -Porolas composites were prepared by a simple method: an impregnation of the Porolas by Fe(III) salts and calcination at 250 °C for 1 h. The sorption capacity and photocatalytic activity of the Fe 2 O 3 -Porolas composites were evaluated by the removal of methylene blue (MB) from model-contaminated water under UV light irradiation in the presence of oxalic acid. The characterization results, particularly from X-ray photoelectron spectroscopy and Mössbauer spectroscopy, confirmed the formation of highly dispersed amorphous Fe 2 O 3 nanoparticles that are embedded in the Porolas matrix. An increase in the content of the embedded Fe 2 O 3 nanoparticles decreased specific surface area (S BET), MB sorption capacity, and apparent photodegradation rate constant (k app) but increased the photodegradation efficiency of MB. The enhancement in MB removal can be attributed to the photocatalytic activities of the Porolas and Fe 2 O 3 nanoparticles (heterogeneous photocatalysis), sorption effect, and leaching of Fe ions in aqueous solution (homogeneous photocatalysis). The scaffold network of the Porolas and highly dispersed Fe 2 O 3 nanoparticles additionally contributed to the enhancement of photocatalytic activity of the Fe 2 O 3 -Porolas composite. Almost complete decolorization of MB (96–98%) and more than 97% TOC were achieved in this study, confirming simultaneous mineralization of both MB and OA in aqueous solution. The Fe 2 O 3 -Porolas composite can be easily prepared and inexpensive to design an easily separable and recyclable photocatalytic system for wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe 2 O 3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (NH 2) and carboxyl groups (COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M (H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μ p = 20,526 μ B for sphere-like nanoparticle clusters and μ p = 20,767 μ B for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). Graphical Abstract Unlabelled Image Highlights • Uniform maghemite nanochains are synthesized by colloidal chemistry. • Shape of the nanochains is quantified by easily computable solidity measure. • Magnetic measurements of the nanochains show superparamagnetic properties. • Magnetic properties point to the shape anisotropy of the nanochains. [ABSTRACT FROM AUTHOR]

Abstract A novel application of geopolymers for the catalytic cleaning of biomass-derived syngas is reported. Powders of metal oxides, i.e. Fe 2 O 3 and Mn 2 O 3 , were dispersed in a geopolymer matrix, to produce composites in granular form for fixed bed application. Additionally, a mixed Fe/Mn composite was produced to explore the combined effects of the two oxides. The activity of the new catalysts was investigated in real gasification conditions by means of a double fixed bed reactor, at 700, 800 and 900 °C. All the systems promoted an appreciable tar removal, while FE-SEM and MIP analyses demonstrated their stability at the process conditions. The best performances were obtained using the composite including both Mn and Fe oxides, which registered a tar decomposition up to 86% compared to inert sand, and 50% compared to olivine. A reasonable explanation was provided by TPR and XRD analyses, which pointed out an easier reducibility of this system. Graphical abstract Image 1 Highlights • Novel geopolymer-based catalysts with Fe 2 O 3 and Mn 2 O 3. • Low cost and green synthesis/disposal. • Efficient tar decomposition at 700, 800 and 900 °C. • Synergistic interaction of Mn 2 O 3 and Fe 2 O 3. [ABSTRACT FROM AUTHOR]

Abstract The influence of 0.01–2 mol% Fe 2 O 3 powder addition on the microstructure, mechanical and optical properties, and hydrothermal stability of highly-translucent 3Y-TZP ceramics is assessed and compared with commercially available co-precipitated 0.18 mol% Fe 2 O 3 doped ZrO 2 powder-based ceramics. Only those ceramics with up to 0.1 mol% Fe 2 O 3 resulted in a proper shade for dental zirconia ceramics, with a typical composition of 87 vol% t -ZrO 2 and 13 vol% c -ZrO 2. The amount of cubic phase increased at higher Fe 2 O 3 content. The hardness (∼13 GPa) and fracture toughness (∼3.6 MPa m1/2) of the 0.01 mol% - 0.1 mol% Fe 2 O 3 doped 3Y-TZP was comparable, whereas the hardness decreased above 0.5 mol% Fe 2 O 3 and the fracture toughness decreased above 2 mol% Fe 2 O 3. The hydrothermal ageing resistance slightly increased for Fe 2 O 3 concentrations up to 1 mol%, whereas the translucency slightly decreased with increasing Fe 2 O 3 content. [ABSTRACT FROM AUTHOR]

Abstract The iron-oxide nanoparticles (IONPs) filled multi-walled carbon nanotubes (IONP-MWCNTs hybrid) were directly synthesized via chemical vapour deposition method with acetylene as a carbon source. The bare IONPs were synthesized by hydrothermal method and the prepared bare IONPs were employed as a catalytic-support as well as a filling agent for the synthesis of IONP-MWCNTs hybrid at about 800 °C under atmospheric pressure. The synthesized IONP-MWCNTs hybrid was characterized by various physicochemical techniques including X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The results demonstrate that the carbon nanotubes were successfully generated on the IONPs with the high yield because of unique carbon-iron metal interactions. An average diameter of synthesized IONPs and MWCNTs are around 9 and 50 nm, respectively. In addition, the HRTEM images and Raman spectrum confirms the obtained IONP-MWCNTs hybrid is well graphitic without major carbonaceous impurities. The electrochemical activity of the synthesized IONP-MWCNTs hybrid was performed in 2 M KOH using a three-electrode cell setup with a saturated Ag/AgCl as a reference electrode and a platinum plate as a counter-electrode by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. This electrode active material (IONP-MWCNTs hybrid) possess excellent supercapacitive behaviour and has excellent cyclic stability, even after 5000 cycles of charge-discharge at 4 A g−1 as current density. Thus, the synthesized IONP-MWCNTs hybrid will be a suitable as well as an economical electrode active material for high-performance supercapacitors. Graphical abstract Image 1 Highlights • IONPs was successfully filled inside of the MWCNTs by a simple CVD method. • Fabricated IONP MWCNTs delivered a high C s about 231 F g−1 at 4 A g−1. • This electrode material has excellent cyclic stability even after 5000 cycles. • Moreover, this method offers an economical way to get high-performance capacitors. [ABSTRACT FROM AUTHOR]

Abstract The super-paramagnetic iron oxide nanoparticles (SPIONs) were synthesized using an environmentally friendly method. The SPIONs with mainly carbohydrate coatings were simply synthesized using a natural, zero calorie sweetener (Stevia) extract (as both reducing and stabilizing agents). The resulting SPIONs were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), vibrating-sample magnetometer (VSM) and Zeta potential test. The SPIONs (smaller than 25 nm) are very stable due to bio-molecular coating because having a zeta potential of −41.1 mV creates opposing forces between nanoparticles and prevents them from gathering. The biogenic SPIONs were able to counteract the effects of oxidative metabolites as studied with the antioxidant activity with an IC 50 of 65 μg/ml. This feature shows the capability of these nanoparticles in designing potential biomedical applications. Graphical abstract Schematic representation of green synthesis of the magnetic iron oxide nanoparticles. Image Highlights • Fe 3 O 4 iron oxide nanoparticles was smaller than 25 nm in size. • The magnitude of the potential Zeta was calculated −41.1 mV. • These biogenic NPs can easily be collected or removed from the environments. [ABSTRACT FROM AUTHOR]

Abstract A mechanochemical protocol was applied to the synthesis of a magnetic material based on iron oxide nanoparticles and Al-SBA-15. Full characterization of the prepared Fe 2 O 3 /Al-SBA-15 evidenced the effective functionalization of the aluminosilicate surface. Particularly, TEM analysis revealed that the mechanochemical protocol did not considerable affect the hexagonal ordered structure of Al-SBA-15. DRIFT experiments of Fe 2 O 3 /Al-SBA-15 showed interesting acidic properties, which can be further associated to a good catalytic performance. The catalytic behavior of the prepared material was tested in the oxidation of vanillyl alcohol to vanillin, displaying an excellent activity and selectivity. The material resulted to be highly stable in the aforementioned reaction, without considerable decrease of conversion after 10 reuse cycles. Graphical abstract Unlabelled Image Highlights • Simple mechanochemical synthesis of Fe 2 O 3 /Al-SBA-15. • Efficient oxidation of vanillyl alcohol to vanillin. • Highly active oxidation catalysts (>99% conversion, 88% selectivity). • Stable mechanochemical systems with almost full initial activity after ten reuses. [ABSTRACT FROM AUTHOR]

Abstract Magnetic hyperthermia is one of the most effective methods for treatment of cancer. In this work we discuss synthesis of magnetic iron oxide nanorods (IONRds) and their application for enhanced magnetic hyperthermia. By microwave irradiation the monodisperse water-soluble IONRds with clear morphology were obtained. Magnetic measurements showed that such IONRds have high value of coercivity (141 Oe). Moreover, hyperthermia experiments with synthesized samples were carried out. At the frequency and field strength of alternating magnetic field (AMF) f = 261 kHz H = 20 kA m−1 the specific absorption rate (SAR) and intrinsic loss power (ILP) values were equal to 147 W g−1 and 1.4 nHm2 kg−1 respectively, which confirms the efficiency of synthesized nanorods in hyperthermia applications. [ABSTRACT FROM AUTHOR]

Abstract Point-of-use water treatment technologies can help mitigate risks from drinking water contamination, particularly for metals (and metalloids) that originate in distribution systems (e.g., chromium, lead, copper) or are naturally occurring in private groundwater wells (e.g., arsenic). Here, composite nanofibers of polyacrylonitrile (PAN) with embedded hematite (α-Fe 2 O 3) nanoparticles were synthesized via a single-pot electrospinning synthesis. A core-shell nanofiber composite was also prepared through the subsequent hydrothermal growth of α-Fe 2 O 3 nanostructures on embedded hematite composites. Properties of embedded hematite composites were controlled using electrospinning synthesis variables (e.g., size and loading of embedded α-Fe 2 O 3 nanoparticles), whereas core-shell composites were also tailored via hydrothermal treatment conditions (e.g., soluble iron concentration and duration). Although uptake of Cu(II), Pb(II), Cr(VI), and As(V) was largely independent of the core-shell variables explored, metal uptake on embedded nanofibers increased with α-Fe 2 O 3 loading. Both materials exhibited maximum surface-area-normalized sorption capacities that were comparable to α-Fe 2 O 3 nanoparticle dispersions and exceeded that of a commercial iron oxide based sorbent. Further, both types of composite exhibited strong performance across a range of environmentally relevant pH values (6.0–8.0). Notably, core-shell structures, with a majority of surface accessible α-Fe 2 O 3 , performed far better than embedded composites in kinetically limited flow through systems than was anticipated from their relative performance in equilibrium batch systems. Core-shell nanofiber filters also retained much of the durability and flexibility exhibited by embedded nanofibers. Additional tests with authentic groundwater samples demonstrated the ability of the core-shell nanofiber filters to remove simultaneously both As and suspended solids, illustrating their promise as a nano-enabled technology for point-of-use water treatment. Graphical abstract Image 1 Highlights • Two polymer-iron oxide nanofiber composites were synthesized via electrospinning. • Hematite was either embedded into or coated as a shell on polyacrylonitrile fibers. • Both composites were cohesive and robust nanofiber networks. • Both composites effectively removed As(V), Cr(VI), Cu(II), and Pb(II) in batch. • Core-shell nanofibers were superior for treatment in flow-through systems. [ABSTRACT FROM AUTHOR]

Highlights • An alternative method for CuSO 4 has been proposed using a low copper content concentrate. • A thermodynamics assessments was made in order to support the process. • The SO 2 (g) enrichment has significant effects on reaction system. • The proposed methodology allowed the complete separation of Cu from Fe. • It was observed that the roasting must be conducted above 600 °C in order to separate Cu and Fe. Abstract Concentrates containing sulphide minerals are an important raw material source in the extractive metallurgy of nonferrous metals. This study aims to evaluate the pyrometallurgical processing of a sulphide concentrate with a relatively low copper content through an alternative methodology (roasting-leaching route), in order to selectively obtain CuSO 4 and Fe 2 O 3 for the chemical industry. The thermodynamic behaviour of the concentrate was evaluated in order to identify the conditions to fulfil the aforementioned selectivity. The presence of SO 2 (g) in the reaction system could be responsible for increasing CuSO 4 stability without compromising FeSO 4 dissociation. Subsequently, experiments were carried out to evaluate the temperature and chemical composition of the atmosphere. Both obtained products and raw materials were characterized using common techniques (e.g. X-Ray Diffraction and SEM/EDS). Finally, some roasting products were submitted to water solubilisation tests in order to verify, in practice, the selective conversion of copper and iron sulphides into CuSO 4 and Fe 2 O 3. The proposed methodology allowed for complete separation of Cu from Fe, roasting experiments conducted at 873 K (600 °C) and 923 K (650 °C). This was observed in praxis through the formation of a blue liquor, typically copper sulphate, and a brown solid residue which was deprived of Cu, as verified by the applied characterization methods. [ABSTRACT FROM AUTHOR]

Abstract Flexible electrochromic organo-tungsten-iron oxide (WFe x O y C z) films are rapidly deposited onto flexible (60 Ω/□ polyethylene terephthalate/indium tin oxide; PET/ITO) substrates by a low temperature-atmospheric pressure-plasma polymerization method with an atmospheric pressure plasma jet (APPJ) for a short exposed duration of 48 s. The precursor vapors of tungsten hexacarbonyl [W(CO) 6 ] and biscyclopentadienyl iron [ferrocene; Fe(C 5 H 5) 2 ] are mixed with O 2 gases at various gas flow rates, injected into air plasma jet and sprayed onto PET/ITO substrates at room temperature (~23 °C) and at atmospheric pressure (1.013 × 105 Pa). Flexible electrochromic WFe x O y C z films are synthesized with a specific addition of oxygen gases with superior lithium electrochromic properties as demonstrated by a potential sweep alternating between −1 V and 2 V at a scan rate of 40 mV/s in a 1 M LiClO 4 -propylene carbonate electrolyte. With amorphous WFe x O y C z films produced with an APPJ by adding oxygen gases at a specific flow rate of 0.5 sccm, a high value in oxygen deficiency up to 0.189 allows more Li+ ions to intercalate into and deintercalate out of the film. Significant coloration and bleaching are proven by the high values in optical transmittance modulation (Δ T) of up to 70.3%, optical density (Δ OD) up to 0.77 and color efficiency (η) up to 61.3 cm2/C, at a wavelength of 800 nm, respectively. Highlights • Rapid deposition of flexible WFe x O y C z film using atmospheric pressure plasma jet. • Enhanced electrochromic performance of WFe x O y C z films by addition oxygen gases. • Notable light modulation on WFe x O y C z films is achieved. • Porous surfaces of WFe x O y C z films offer reversibly coloration and bleaching. [ABSTRACT FROM AUTHOR]

Abstract Magnetic nanoparticles (MNP) have been developed in the recent years for various applications like cell separation, immunoassay, and drug delivery. The present study involves the synthesis of stable, biocompatible Iron oxide MNP by coprecipitation of ferric chloride and ferrous chloride with Polyethylene glycol (PEG) as a surfactant to coat the nanoparticles twice. Scanning electron microscopic (SEM) images confirm the formation of uniform MNPs of size 12–17 nm. The peak at 582.2 cm−1 in the Fourier transform infrared spectrum (FTIR) corresponds to the Fe–O bond and the peak at 1104.1 cm−1 corresponds to a characteristic peak of PEG binding to the iron core. Tumor tissues selectively targeted with MNPs when placed in a magnetic field increases the temperature of the tumor tissues. The phantom study shows that there is a minimum of 1.3 °C and a maximum of 6.7 °C rise in temperature with increasing concentration of the nanoparticles embedded in the phantoms; this proved the possibility of enhancement of thermal images using MNPs and its usage for thermal ablation of cancer. MNPs can also be used as a contrast agent for magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

Abstract Using a rapid, open-atmosphere flame synthesis technique, iron-oxide nanoparticles (α-Fe 2 O 3) and nanocrystals (γ-Fe 2 O 3) and carbon nanotubes (CNTs) are grown directly on stainless steel substrates. Multiple inverse-diffusion flames provide both oxide species (H 2 O and CO 2) and carbon species (CH 4 , CO, C 2 H 2), at elevated temperature, conducive for the growths of iron-oxide nanoparticles/nanocrystals and CNTs. The growth of α-Fe 2 O 3 nanoparticles occurs at 500 °C. At a temperature of 850 °C, the growth of CNTs occurs on type 304 stainless steel, while γ-Fe 2 O nanocrystal films are grown on 304 L and 316 L stainless steels with relatively lower innate carbon content. Interestingly, a temperature-step process, where 304 stainless steel substrate is initially at 500 °C and then increased to 850 °C, distinctly converts the "seed" α-Fe 2 O 3 nanoparticles into larger γ-Fe 2 O 3 nanocrystals, with some scattered CNTs. Strategically time-varied local conditions should produce different compositional ratios of iron-oxide/CNT hybrid films, as well as targeted functionally-graded nanostructures and nanocomposites. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The stability of Fe 2 O 3 -MgAl 2 O 4 was investigated over 1000 redox cycles. • 10Fe 2 O 3 -MgAl 2 O 4 has exhibiting stability in terms of morphology. • 50Fe 2 O 3 -MgAl 2 O 4 performs best in terms of overall CO yield. • Deactivation through sintering occurs in all materials. • Phase transformation predominantly causes in 30Fe 2 O 3 -MgAl 2 O 4 and 50Fe 2 O 3 -MgAl 2 O 4. Abstract The stability of Fe 2 O 3 -MgAl 2 O 4 oxygen storage materials (OSMs) was investigated over 1000 redox cycles using H 2 as reductant and CO 2 as oxidant. Three different materials, with a nominal Fe 2 O 3 amount of 10 wt%, 30 wt% and 50 wt%, were evaluated. Characterization techniques such as N 2 adsorption, XRD and STEM-EDX were applied to study the evolution of morphological and crystallographic properties. XRD results show that Fe is incorporated in the MgAl 2 O 4 lattice of the as prepared materials, yielding a Mg-Fe-Al-O spinel structure. After redox cycling, part of Fe still remains within the spinel. The results of redox cycling reveal superior properties for 10Fe 2 O 3 -MgAl 2 O 4 , exhibiting stability in terms of morphology and, with an average space-time yield of 700 mmol CO s−1 kg Fe −1, the highest activity among the OSMs studied. However, 50Fe 2 O 3 -MgAl 2 O 4 performs best in terms of overall CO yield, i.e. 0.6 mol CO kg OSM −1, more than twofold higher compared to 10Fe 2 O 3 -MgAl 2 O 4 and 30Fe 2 O 3 -MgAl 2 O 4 even after 1000 cycles. Deactivation through sintering occurs in all three materials, though to a lesser extent for 10Fe 2 O 3 -MgAl 2 O 4. Phase transformation to a Mg x Fe 1-x O phase predominantly causes a loss of oxygen storage capacity in 30Fe 2 O 3 -MgAl 2 O 4 and 50Fe 2 O 3 -MgAl 2 O 4. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pulsed laser ablation of iron in air led to magnetite and iron nitrides formation. • Lamellas and rolls appear in the sample that was ablated in air, not in Ar-O 2 mixture. • Thermal treatment allowed control of the composition and structure of the material. • Materials obtained with different properties are in demand for different applications. Abstract Magnetic nanoparticles were obtained using the nanosecond pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) of an iron target in air at atmospheric pressure. The particles obtained were further annealed at four different temperatures. The composition, structure and properties of all obtained powders were investigated using X-ray diffraction (XRD), DSC, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, TEM, SAED and other techniques. The initial sample was found to contain monoclinic magnetite and iron nitrides. Presumably, magnetite presents in the form of spherical particles with the distribution maximum of 12–15 nm, and nitrides take the form of lamellas and rolls. Thermal treatment of the sample led to particle enlargement and phase transformations, first, to cubic magnetite, then to a Fe 3 O 4 , α-Fe 2 O 3 and γ-Fe 2 O 3 mixture, and finally to the pure hematite phase. Zeta-potential, BET surface area and magnetic properties changed with the annealing as well. The obtained materials exhibited different properties that make them in demand in different fields, from biomedicine to technology. [ABSTRACT FROM AUTHOR]

Tunable, one-dimensional (1D) nanofiller assembly using oscillating magnetic fields in the low frequency range (<5 Hz) is studied as a scalable and energy-efficient method to structure nanofillers within viscous matrices to deliver anisotropic, multi-functional polymer nanocomposites (PNCs). In this work 1D assembly tailoring was first experimentally studied and demonstrated using the model system of superparamagnetic iron oxide nanoparticles (SPIONs, 15 nm, 0.02–0.08 vol%) in DI water using varying magnetic fields (0–5 Hz frequency, 10–100 G magnetic flux density, and square and sinusoidal waveforms). In addition to lateral assembly of nanofillers, when the field oscillation is turned on, transverse assembly can be introduced as the magnetic moments of the particles respond to the changing fields by Brownian rotation. The degree of transverse assembly, in balance with lateral assembly and the resulting nanofiller patterns, was observed to be determined by the magnetic field parameters, magnetic responsiveness of the nanofillers, and the matrix viscosity. Based on this assembly study, PNCs consisting of ferrimagnetic iron oxide nanofillers in a thermoset polymer, with two different linear nanoparticle patterning, were successfully fabricated using small magnetic fields (<100 G) even in a viscous matrix (70 cP) with a short assembly time of 30 min. This work can contribute to scalable manufacturing and thus bulk application of multi-functional PNCs enabled by more precise nanofiller and interface structuring. [ABSTRACT FROM AUTHOR]

Highlights • Morphology engineering on iron oxides is carried out via an electrochemical method. • Morphology transition from zero-dimension to one-dimension is realized. • Iron oxide electrode delivers a high capacity of 184 mAh g−1 at 2 A g−1 (∼6C rate). • The Ni/Fe full cell exhibits a good energy density of 82.3 Wh kg−1. Abstract Aqueous rechargeable Ni/Fe batteries possess potential advantages for large-scale energy storage applications due to their low cost, high safety and fast ion diffusions in electrolyte. However, the electrochemical performance of the iron-based anode is still far from ideal due to particle aggregations. Herein, we carry out the morphology engineering on the iron oxide active materials via a facile electrochemical method to improve its charge storage capability. The morphology transition from zero-dimensional particles to one-dimensional nanorods is realized by tuning the electrolyte composition, while subsequent annealing treatment results in further morphology modification into 3D interconnected nanoparticles (10–20 nm). The hierarchical structure allows facile ion and electron transfers, and the large surface provides various active sites for the charge storage conversion reaction. As a result, even at the high current density of 2 A g−1 (∼6C rate), the iron oxide electrode can still deliver a high specific capacity of 184 mAh g−1. At the same time, the morphology integrity and stability of the electrode leads to a good cycle life, with 87.5% capacity retained upon 5000 cycles. The Ni/Fe full cell assembled with the iron oxide anode and a Ni-Co double hydroxide cathode exhibits a good energy density of 82.3 Wh kg−1 at the power density of 3.3 kW kg−1. Our fundamental study would provide new insights for the electro-deposition of iron-based materials and endow new opportunities for the fabrication of high-performance iron-based electrodes for energy storage systems. [ABSTRACT FROM AUTHOR]

Abstract Background Site-specific multimodal nanoplatforms with fluorescent-magnetic properties have great potential for biological sciences. For this reason, we developed a multimodal nanoprobe (BNPs-Tf), by covalently conjugating an optical-magnetically active bimodal nanosystem, based on quantum dots and iron oxide nanoparticles, with the human holo-transferrin (Tf). Methods The Tf bioconjugation efficiency was evaluated by the fluorescence microplate assay (FMA) and the amount of Tf immobilized on BNPs was quantified by fluorescence spectroscopy. Moreover, relaxometric and fluorescent properties of the BNPs-Tf were evaluated, as well as its ability to label specifically HeLa cells. Cytotoxicity was also performed by Alamar Blue assay. Results The FMA confirmed an efficient bioconjugation and the fluorescence spectroscopy analysis indicated that 98% of Tf was immobilized on BNPs. BNPs-Tf also presented a bright fluorescence and a transversal/longitudinal relaxivities ratio (r 2 / r 1) of 65. Importantly, the developed BNPs-Tf were able to label, efficiently and specifically, the Tf receptors in HeLa cells, as shown by fluorescence and magnetic resonance imaging assays. Moreover, this multimodal system did not cause noteworthy cytotoxicity. Conclusions The prepared BNPs-Tf hold great promise as an effective and specific multimodal, highly fluorescent-magnetic, nanoplatform for fluorescence analyses and T 2 -weighted images. General significance This study developed an attractive and versatile multimodal nanoplatform that has potential to be applied in a variety of in vitro and in vivo studies, addressing biological processes, diagnostic, and therapeutics. Moreover, this work opens new possibilities for designing other efficient multimodal nanosystems, considering other biomolecules in their composition able to provide them important functional properties. Graphical abstract Unlabelled Image Highlights • Transferrin (Tf) was efficiently conjugated to bimodal nanoparticles (BNPs). • BNPs-Tf presented high fluorescence and transversal relaxivity. • BNPs-Tf labeled efficiently cell Tf receptors by fluorescence /relaxometric assays. • BNPs-Tf did not cause significant toxicity in HeLa cells, under the conditions applied. • BNPs-Tf hold great promise for fluorescence analyses and T 2 -weighted images. [ABSTRACT FROM AUTHOR]

Abstract Here we report immobilization of glucose oxidase (GOx) on magnetic silica (Fe 3 O 4 -SiO 2) and alumina (Fe 3 O 4 -Al 2 O 3) functionalized with amino groups using glutaraldehyde as a linker. Magnetic support based biocatalysts demonstrate high catalytic activity in d -glucose oxidation to D-gluconic acid at pH 5–7.5 and temperature of 30–50 °C with the best activities of 95% and 91% for magnetic silica and alumina, respectively. A comparison of magnetic and non-magnetic alumina and silica shows a significant enhancement of the relative catalytic activity for magnetic supports, while the silica based biocatalysts show a higher activity than the biocatalysts based on alumina. A noticeably higher activity of GOx immobilized on magnetic supports is explained by synergy of the GOx inherent activity and enzyme-like activity of iron oxide nanoparticles, while the enhancement with silica based catalysts is most likely due to a larger pore size and stronger Brønsted acid sites. Excellent relative activity of Fe 3 O 4 -SiO 2 -GOx (95% of native GOx) in a tolerant pH and temperature range as well as high stability in a repeated use (6% relative activity loss after five catalytic cycles) makes this catalyst promising for practical applications. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • Hydrothermally synthesized iron oxide and zinc oxide nanocomposite. • Adsorptive removal of Cr(VI) ions using iron oxide and zinc oxide nanocomposite. • Imparting antibacterial and antioxidant properties to the treated water using iron oxide and zinc oxide nanocompsite. • Achieving removal efficiency of 97.8% for Cr(VI) ions using iron oxide and zinc oxide nanocomposite. • Achieving adsorption capacity of 36.5 mg/g using iron oxide and zinc oxide nanocomposite. Abstract The synthesis of a multifunctional composite using Fe 2 O 3 and ZnO endowed with antioxidant and antibacterial properties for the adsorption of chromium(VI) ions was reported. Typical approaches of eliminating metal ions from wastewater focus on removing only the contaminants. In this research, a composite was developed that is not only highly efficient in removing Cr(VI) ions but also imparts antibacterial and antioxidant properties to the treated water. The characterizations of the composite were conducted using powder X-ray diffraction (pXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy-Energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET). BET surface area revealed that the sheet-like Fe 2 O 3 were present alongside hexagonal ZnO rods. The adsorption data corroborated well with Freundlich isotherm (R 2= 0.99844) better than the Langmuir model (R 2= 0.97993) indicating the prevalence of multi-layer sorption. Pseudo-second-order kinetics model described the adsorption process well implying chemisorption was the major contributor to the adsorption capacity. The composite exhibited additional useful character by inhibiting up to 12% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals when used in the concentration range of 10–50 µL. It also showed antibacterial property by removing more than 99% of Staphylococcus aureus after an exposure time of six hours. It is proposed that Fe 2 O 3 –ZnO composite may be highly effective for multi-purpose water treatment. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

A laser-based technology is presented for fabrication of oriented nanowires composed by nanoparticles. The nanowires were produced by nanosecond pulsed laser deposition in air at atmospheric pressure in the presence of an external magnetic field. The technology described is relevant to the preparation of nanowires of magnetic materials. Applying an external magnetic field during the deposition resulted in the formation of nanowires with lengths of a few microns oriented longitudinally to the magnetic field lines. The influence was investigated of the process parameters, namely, laser fluence, target-substrate distance, and wavelength used for ablation, on the morphology of the deposited samples. It was found that the degree of the nanowires’ orientation increased with the increase of the target-substrate distance. Also, the density of the deposited material was influenced by the laser fluence applied and by the wavelength used. [ABSTRACT FROM AUTHOR]

Highlights • PCB28 degradation didn’t accord with H 2 O 2 decomposition catalyzed by four iron oxides. • The stoichiometric efficiency of OH formation showed α-FeOOH > α-Fe 2 O 3 > Fe 3 O 4 ≈ H 2 Fe 2 O 4. • Quenching O 2 − markedly decreased OH formation catalyzed by α-Fe 2 O 3 , Fe 3 O 4 or H 2 Fe 2 O 4. • Quenching O 2 − greatly increased OH formation catalyzed by α-FeOOH. • Both OH and O 2 − contributed on PCB28 degradation in iron oxide-catalyzed Fenton systems. Abstract The catalytic performance of iron oxides in 2,4,4′-trichlobiphenyl (PCB28) degradation following an order of goethite > magnetite > hydrated iron(III) oxide > hematite was observed in four iron oxides catalyzed Fenton-like reactions, which was not consistent with the stoichiometric efficiency of OH generation. This result indicates that OH was not the sole active species responsible for PCB28 degradation in four iron oxides catalyzed Fenton-like systems. The reductive degradation of hexachloroethane (HCE) was 76.8%, 58.7%, 46.1% and 37.6% for magnetite, goethite, hematite and hydrated iron(III) oxide, respectively, further suggesting that both oxidative species (OH) and reductive species (HO 2) simultaneously contributed on PCB28 degradation. The addition of tert -butyl alcohol (OH scavenger) decreased the amount of 7-hydroxycoumarin (7-HC, OH indicator) by 42%, 77%, 97%, and 97% for magnetite, goethite, hematite, and hydrated iron(III) oxide, respectively. Meanwhile, the addition of p -benzoquinone (HO 2 scavenger) only reduced the amount of 7-HC by 77%, 27%, and 33.5% for magnetite, hematite, and hydrated iron(III) oxide, respectively; but increased the amount of 7-HC by 126.7% in the goethite/H 2 O 2 system. This result indicates that the mechanism of OH generation from H 2 O 2 catalyzed by four iron oxides was different. For goethite, the surface lattice iron was primarily responsible for activating H 2 O 2 to form reactive species (OH and HO 2) and thereby degrade pollutants on the oxide surface. For magnetite, both the surface lattice iron and the dissolved Fe in solution played an equally important role in catalyzing H 2 O 2 decomposition to form and propagate reactive species for pollutant degradation. For hematite and hydrated iron(III) oxide, the solution phase chain reaction effectively propagated by dissolved Fe should be the primary catalytic mechanism although the chain reaction was initiated by the surface processes. [ABSTRACT FROM AUTHOR]

Abstract Integration of metal oxides with graphene can highly improve their electrochemical performance as promising anode materials for lithium-ion batteries. However, the pulverization, expansion and detachment of metal oxide particles on graphene are still present and lead to the performance degradation after long-term cycling. In this work, TiO 2 nanofilms-coated graphene-SnO 2 and graphene-Fe 2 O 3 are prepared and exhibit exceptional electrochemical performance, especially great cycling stability, because amorphous TiO 2 nanofilms can prevent the pulverization, expansion and detachment of SnO 2 /Fe 2 O 3 nanoparticles on graphene, and increase the flexibility and mechanical strength of graphene hybrid electrodes. Moreover, it is apt to form thin and stable solid-electrolyte interphase layers on the surface of TiO 2 nanofilms rather than the graphene substrate. Accordingly, this novel and facile synthetic procedure offers great promise for the development of high-performance graphene hybrids utilized in various applications such as batteries. Graphical abstract Image 1 Highlights • TiO 2 nanofilms are prepared on the surface of graphene-SnO 2 and graphene-Fe 2 O 3. • TiO 2 nanofilms on graphene hybrids are amorphous and ultrathin. • TiO 2 nanofilms-coated graphene hybrids exhibit superior electrochemical performance. • The structure of graphene hybrids is more stable after coating with TiO 2 nanofilms. [ABSTRACT FROM AUTHOR]

Abstract A simple and cost-effective fabrication of the Zn-doped α-Fe 2 O 3 thin film as a photocathode for solar hydrogen generation was proposed in this study. Transparent Zn-doped α-Fe 2 O 3 films were prepared by a spin-coating process using nontoxic iron chloride as the iron precursor and zinc chloride as an acceptor dopant, and the thermal treatment at 550 °C in air subsequently followed up. X-ray diffraction and Raman spectroscopic characterizations suggest the α-phase to the Zn-doped hematite film, indicating that the incorporation of Zn into the Fe 2 O 3 host lattice is carried out in the absence of phase transition. X-ray photoelectron spectroscopic study otherwise demonstrates the substitution of Fe3+ for Zn2+ in the Zn-doped α-Fe 2 O 3 specimens. Mott-Schottky analysis shows that the Zn dopant functions as the hole acceptor and the carrier density is dictated by the concentration of the zinc precursor. Significantly, a notable cathodic photocurrent of −0.1 mA cm−2 is delivered by the Zn-doped α-Fe 2 O 3 photocathode with a doping level of 10% in the photoelectrochemical measurement. Last but not least, the doping effect on the photo-activity of hematite is systematically investigated that in turn works as the blueprint for materials design in the solar application. Graphical abstract Image 1 Highlights • Zn-doped Fe 2 O 3 films were synthesized by a spin-coating process followed by annealing. • Substitution of Zn ions in the Fe 2 O 3 can be confirmed by XPS and Raman spectra. • High PEC activity of Zn-doped Fe 2 O 3 film was achieved the photocurrent of −0.1 mAcm−2. [ABSTRACT FROM AUTHOR]

We report on glycine-free and glycine-assisted hydrothermal synthesis of microsized superstructures composed of self-assembled hematite nanoparticles. An X-ray powder diffraction measurements of the samples confirm good crystallization of the hematite nanoparticles with hydrothermal reaction time-dependent crystallite sizes in a range from ∼15 nm (45 h) to ∼26 nm (90 h). The FTIR and Raman spectroscopy confirm hematite structure, whereas TEM measurements reveal nanoparticle sub-units (subparticles). The computational analyses of particle shape show that the addition of glycine surfactant in hydrothermal reaction leads to more spherical shape of hematite hierarchical structures and smaller sizes. We found strong coercivity increases (up to ∼3 times) in the samples synthesized in the presence of glycine. The coercivity values from H C  = 1305 Oe (mushroom-like shape synthesized by glycine-free hydrothermal reaction) to H C  = 3725 Oe (sphere-like shape synthesized by glycine-assisted hydrothermal reaction) were obtained at 300 K. These results and their comparison with other described in the literature (e.g. bulk, wires, urchin-like, rods, tubes, plates, star-like, dendrites, platelets, irregular, nanocolumns, spindles, disks hematites, etc.) reveal that the hematite superstructures possess good magnetic properties. We propose that the glycine, oriented subparticles, exchange and dipole-dipole interactions may play an important role in the development of magnetic properties. [ABSTRACT FROM AUTHOR]

Highlights • Air Brayton cycle with two-step Fe 2 O 3 /Fe 3 O 4 solar thermochemical heat storage cycle. • Superior efficiency at very high solar concentrations, Fe 2 O 3 reduction temperatures. • Maximum cycle efficiency of 46% at 4000 suns and Fe 3 O 4 re-oxidation at 30 bar. • Rapid thermal reduction follows pressure-dependent Avrami-Erofe'ev model. • Rapid oxidation shows evidence of multiple mechanisms, warranting further study. Abstract Solar electricity production via an Air Brayton cycle is considered with integrated thermochemical energy storage. The storage is realized via a two-step solar thermochemical cycle based on Fe 2 O 3 /Fe 3 O 4 reduction-oxidation reactions, encompassing (1) the thermal reduction of Fe 2 O 3 to Fe 3 O 4 and O 2 driven by concentrated solar irradiation under vacuum; and (2) the exothermic oxidation of Fe 3 O 4 with a compressed air stream back to Fe 2 O 3. The steps may be decoupled, resulting in a high temperature, pressurized airflow that is expanded across a turbine to produce on-demand electricity. A thermodynamic analysis of the system determined a maximum cycle efficiency of 46.0% at a solar concentration ratio of 4000 suns, an oxidation pressure of 30 bar, and an approximately 5:1 molar flow rate ratio of air to solid Fe 2 O 3 exiting the re-oxidizer. Chemical kinetics for the thermal reduction of Fe 2 O 3 were determined between approximately 1400 and 1700 K using non-isothermal thermogravimetry with heating rates between 10 and 20 K·s−1 and O 2 partial pressures between 0 and 0.05 bar. The rate-limiting reaction mechanism was determined to be nucleation, and kinetic parameters were resolved using an Avrami-Erofe'ev nucleation model with a reaction order of 1.264 ± 0.010. The rate constant followed an Arrhenius-type temperature dependency with an apparent activation energy of 487.0 ± 3.6 kJ·mol−1 and pre-exponential factor 2.768 ± 0.783·1014 s−1. A power-law dependence on O 2 partial pressure of order 8.317 ± 0.233 was determined. Non-isothermal thermogravimetry to examine the oxidation of Fe 3 O 4 to Fe 2 O 3 revealed multiple kinetic regimes, and isothermal thermogravimetry showed the reaction proceeded rapidly, within 20 s, at temperatures greater than 673 K. Solid characterization was carried out using scanning electron microscopy and x-ray powder diffractometry up to temperatures of 1073 K to verify initial and final sample compositions and structures. [ABSTRACT FROM AUTHOR]

The effectiveness of the current UK iron oxide powder suspension formulation, 'C-IOPS-09' (Triton X-100 based), for fingermark or latent fingerprint visualization is shown to be affected by variations between batches of the recommended iron oxide powder from Fisher Scientific (I/1100/53). When incorporated into the C-IOPS-09 formulation, a 2015 powder batch resulted in the detection of ∼19% fewer fingermarks, of broadly reduced contrast, when compared to powder suspension prepared with a 2008 batch of the same product. Furthermore, the 2015 powder batch was found to be unsuitable in experimental reduced-surfactant concentration powder suspension, because it caused surface-wide or background staining. The studies in this paper also investigated the use of Tween 20 surfactant as an alternative to the currently utilised Triton X-100, in preparation for the potential unavailability of Triton X-100 in the future. Powder suspensions prepared with Tween 20 surfactant solutions of 4% and 40% were shown to offer similar effectiveness to the currently recommended C-IOPS-09 formulation, when compared using the same batch of Fisher Scientific iron oxide powder (2008 or 2015). The difference between the 2008 and 2015 iron oxide batches was hence also evident with these alternative surfactant solutions. Particle size distribution analysis of the iron oxide powders in Tween 20 and Triton X-100 based surfactant solutions show that the more effective powder exhibits a higher sub-micrometre particle population than the less effective powder. This work leads to an improved specification for powder suspension formulations. This is demonstrated with an example powder suspension formulation which uses a 10% Tween 20 surfactant solution and iron oxide nanopowder (50-100nm) from Sigma Aldrich, which was shown to visualise 27% more fingermarks than the C-IOPS-09 formulation prepared with the 2015 Fisher Scientific powder batch, in a comparative study. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • MoO 3 /Fe 2 O 3 core-shell redox catalysts prepared. • Calcined catalysts have surface layers comprising Fe 2 (MoO 4) 3 and MoO 3. • Core-shell catalysts exhibit enhanced ethane CL-ODH performance. • Mixed Mo-Fe oxide shell suppresses combustion and increases ODH activity. Abstract Oxidative dehydrogenation (ODH) of ethane offers large reductions in energy consumption and associated greenhouse gas emissions when compared to conventional steam cracking for ethylene production; however, catalytic ODH of ethane using co-fed O 2 requires expensive air separation. As an alternative, we are investigating novel core-shell catalysts that utilize lattice oxygen (O2−) as the sole oxidant and operate in a cyclic redox mode. In this work, redox catalysts having 1, 3 and 6 monolayer (ML) equivalents of MoO 3 on α-Fe 2 O 3 and a stoichiometric ferric molybdate, Fe 2 (MoO 4) 3 , were prepared, characterized by powder x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS), and temperature-programmed reduction (TPR) and evaluated for ethane ODH in a cyclic redox mode at 600 °C. The characterization data are consistent with a core-shell structure for the calcined MoO 3 /Fe 2 O 3 catalysts with a mixed Mo-Fe oxide surface layer. H 2 and ethane TPR evidence that the shell inhibits Fe 2 O 3 reduction and decreases the ethane combustion activity of the fully oxidized catalyst. Covering the Fe 2 O 3 core with MoO 3 also increases ODH activity and ethylene selectivity. In cyclic redox mode at 600 °C, ethylene selectivity was 57–62% for catalysts with 3 and 6 ML equivalents of MoO 3. [ABSTRACT FROM AUTHOR]

Abstract The purpose of the present report was the study and identification of an unspecified sample from a work of art by means only of a microscope coupled to a Raman spectrometer. The origin of the fragment was obscure. The Raman spectra on the virgin sample were giving no results because of a deteriorated surface treatment, in spite of the evident blue color identified by microscopic visual inspection. The sample fragmentation and the preparation of a KBr pellet allowed the distribution of the painting layers of the different components on a flat substrate reducing surface effects. Selecting the areas of different color and focusing there it was possible to identify the pigments from their Raman spectra locally acquired by selective excitation. Raman spectra were assigned by comparison with published databases. It was possible to connect Carbon Black and Orange iron oxide, as documented historically, as constituents of Azurite preparatory layer - "Morellone", according to a technique generally employed to allow the use of Azurite blue pigment on frescos, consequently the identification of typology of work of art was deducted and attributed to a fresco. [ABSTRACT FROM AUTHOR]

Abstract Coal-direct chemical looping hydrogen generation (CLHG) is an innovative technology developed to produce hydrogen with in situ CO 2 capture. Most oxygen carrier (OC) candidates for other chemical looping processes are not suitable for the technology. In this work, potassium modified Fe 2 O 3 /Al 2 O 3 OCs were prepared by co-precipitation method, and screening tests were conducted to selected appropriate OC and char particle size. Experiments on the technology were carried out in a fixed bed reactor to evaluate the redox and cyclic performance of the composite OCs using Shenmu char as fuel. The OC residues in the process were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and N 2 adsorption analyzer. Moreover, the variations of potassium content in OC residues were also discussed. The results show that the appropriate particle ranges were 425 μm–600 μm for OC and less than 75 μm for char. During the first cycle, the carbon conversion could reach about more than 95% within 45 min and the total H 2 concentration under an N 2 -free basis in steam oxidation period was about 99.3%. In the multi-cycle tests, the carbon conversion and hydrogen yield remained almost unchanged during the first three cycles and decreased thereafter. The selectivity toward CO 2 was less than 80% during the first three cycles, increased in the next five cycles and reached about 99.3% in the 8th cycle. The OC exhibited a good anti-sintering ability and stable pore structure in the eight cycles. The decrease of potassium content in OCs was the reason for the decline of carbon conversion and hydrogen yield, and the supplement of K 2 CO 3 could recover the reactivity of OCs. Highlights • A new type oxygen carrier for coal-direct chemical looping hydrogen generation. • The oxygen carrier had a good anti-sintering and stable pore structure. • The total H 2 concentration under an N 2 -free basis was about 99.3%. • Potassium content in oxygen carrier was related to the reactivity of oxygen carrier. [ABSTRACT FROM AUTHOR]

Abstract Oxygen-defective Fe 2 O 3 /CoO x nanorod array composite films are prepared using a facile and environmentally friendly photodeposition method followed by annealing in oxygen deficient atmosphere. Compared with the original Fe 2 O 3 /CoO x sample, the optimized oxygen-defective Fe 2 O 3 /CoO x composite film electrode annealed at 250 °C has a 120 mV negative shifting of overpotential and lower Tafel slope. Moreover, the optimized oxygen-defective Fe 2 O 3 /CoO x composite film electrode exhibits competitive OER stability for 16 h. This can be attributed to numerous active sites on oxygen-defective CoO x and its weak crystallinity that promises excellent activity as well as stability. Furthermore, the amount of oxygen vacancies in CoO x can be finely tuned by changing annealing temperature. Based on XPS spectra and electrochemical analysis results, we show the relationship between the electronic states of Co and its electrocatalytic OER activity. The results may find broad applications in designing highly efficient catalysts for electrochemical process. Graphical abstract Unlabelled Image Highlights • Photodeposited CoO x on Fe 2 O 3 nanorod array can enhance electrochemical active sites. • Amount of oxygen vacancies in CoO x can be tuned by altering thermal temperature. • Effect of Co electronic structure on OER performance is clarified for the first time. • Oxygen-defective CoO x with weak crystallinity promises excellent OER performance. [ABSTRACT FROM AUTHOR]

Today, one of the most important global tasks is the treatment of waste water from various pollutants, including heavy metal. Adsorption is a promising method of wastewater treatment in terms of efficiency and cost. In this paper, the Al/Fe oxide-oxyhydroxide composite powders, prepared by hydrothermal method using metal sulfate solutions and urea as precursors, are investigated as adsorbents for chromium. The influence of the [Al 3+ ]:[Fe 3+ ] ratio on the phase composition, textural properties, morphology, and thermal effects of composites was also investigated. It is shown that the maximum specific surface area (190 m 2 /g) is reached for samples synthesized from solutions with [Al 3+ ]:[Fe 3+ ] = 1:0 and 1:1. Cr(VI) adsorption from solutions was performed under static (batch adsorption) and dynamic (column adsorption) conditions. It is shown that the presence of sulfate ions on the surface of Al-containing samples suppresses the Cr(VI) adsorption. The maximum adsorption capacity in batch adsorption (3.66 mg/g) has a sample synthesized from solutions with [Al 3+ ]:[Fe 3+ ] = 1:6, which is characterized by a high (but not maximal) surface area (102 m 2 /g), a low content of sulfates and maximum zeta potential. Sorption experiments showed that the mean free adsorption energy is below 8 kJ/mol for all samples, indicating the adsorption process as the physical in nature and suggesting the possibility of Cr(VI) desorption and adsorbent regeneration. Based on the results of fixed-bed adsorption experiments, an atypical form of breakthrough curves is noted, as well as an increase in sorption capacity of about 4–5 times as compared with batch adsorption. [ABSTRACT FROM AUTHOR]