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In order to encapsulate nuclear wastes (NW) enriched in Uranium, they have been designed and obtained vitrified matrices of iron aluminum phosphates including substitution of U by Bi. These glasses have been designed and obtained formulating all from the starting binary composition: 60P 2 O 5 ·40Fe 2 O 3 where the Fe/P ratio was 0.67. The thermal behavior has been investigated by DTA/TG analysis and thermal expansion, as well as identification of some phases by TEM/EDS. The vitrified structures are difficult to crystallize as is the case of the (Fe + U) contents in the range of 0.50 per P atom. Glasses with Bi-oxide are less resistant to crystallization than those containing U. The glasses here investigated depict a reasonable water chemical stability due to the high percentage of P O Fe O bonds and the presence of U (4+ to 6+). Lately, it has been also investigated the calcination of simulated miniplates of Si 2 U 3 /Al having additions of these glasses and U 3 O 8 to dilute this Uranium enriched in MTR combustible (Material Testing Reactor). [ABSTRACT FROM AUTHOR]

The sodium intercalation of mixed – valence iron phosphate Fe 3 2+ Fe 4 3+ (PO 4 ) 6 results in drastic transformation of its physical properties. The parent compound Fe 7 (PO 4 ) 6 reaches magnetically ordered state through succession of phase transitions at T N1  = 45.5 K and T N2  = 16 K marked by sharp singularities in both specific heat C p and magnetic susceptibility χ. The introduction of sodium suppresses the formation of antiferromagnetic state down to T N  = 33 K in Na 0.65 Fe 7 (PO 4 ) 6 . The low temperature phase transition in this compound smears being substituted by broad anomalies in magnetization and specific heat related to the spin/charge disorder effects. The sharp well resolved electron spin resonance spectra in parent material transform into asymmetric broad line in sodium – intercalated substance. The dielectric permittivity ε of Fe 7 (PO 4 ) 6 demonstrates a kink at T N2 , while no singularity marks T N1 . No features accompany magnetic phase transition in dielectric property of Na 0.65 Fe 7 (PO 4 ) 6 but ε reaches the relaxation maxima at high temperatures which can be attributed to the freezing of sodium ions. [ABSTRACT FROM AUTHOR]

Iron hydroxyl phosphate (Fe 3 (PO 4 ) 2 (OH) 2 ) microspheres with diameters of several micrometers have been successfully prepared using Fe(NO 3 ) 3 ·9H 2 O and NaH 2 PO 4 ·2H 2 O in a mixed solvent of deionized water and glycerin by a facile one-step solvothermal method. The crystal phase of the product changes from poorly crystallized FePO 4 ·2H 2 O nanoparticles into well-crystallized Fe 3 (PO 4 ) 2 (OH) 2 microspheres as the amount of glycerin increases. The as-prepared Fe 3 (PO 4 ) 2 (OH) 2 microspheres can transform into FePO 4 through thermal treatment at 800 °C in air. The cytotoxicity tests show that the as-prepared Fe 3 (PO 4 ) 2 (OH) 2 microspheres have good biocompatibility. We expect that the as-prepared Fe 3 (PO 4 ) 2 (OH) 2 microspheres are promising for the applications in various fields. [ABSTRACT FROM AUTHOR]

A type of biochar-supported iron phosphate nanoparticle stabilised by a sodium carboxymethyl cellulose (CMC@BC@ Fe 3 (PO 4 ) 2 ) composite was synthesised to remediate cadmium (Cd)-polluted soil. The surface morphology and functional groups of the composite were characterised by scanning electron microscopy and Fourier transform infrared spectrometry, respectively. Batch experiments showed that the composite (soil-to-solution ratio 1 g:10 mL) could effectively immobilise Cd in soil. The immobilisation efficiency of Cd was 81.3% after 28 days of remediation, and physiological-based extraction test bioaccessibility was reduced by 80.0%. The results of sequential extraction procedures indicated that the transformation from more easily extractable Cd to the least available form was responsible for the decrease in Cd bioavailability in soils. Plant growth experiments proved that the composite could inhibit Cd uptake to the belowground and aboveground parts of cabbage mustard by 44.8% and 70.2%, respectively, thus promoting cabbage mustard growth and development after remediation. [ABSTRACT FROM AUTHOR]

A new iron phosphate, disodium calcium manganese(II) iron(III) tris- (phosphate), Na2CaMnFe(PO4)3, has been synthesized as single crystals by the flux technique. This compound crystallizes in the monoclinic space group C2/c. The structure belongs to the alluaudite structural type and thus, it obeys the X(2)X(1)M(1)M(2)2(PO4)3 general formula. Both the X(2) and X(1) sites are fully occupied by sodium, while M(1) is occupied by calcium and M(2) exhibits a statistical distribution of iron and manganese. [ABSTRACT FROM AUTHOR]

A non-aqueous approach was developed to synthesize iron phosphate cathode materials by the atomic layer deposition (ALD) technique. Deposition of iron phosphate thin films was achieved on nitrogen-doped carbon nanotubes (NCNTs) by combining ALD subcycles of Fe 2 O 3 (ferrocene-ozone) and PO x (trimethyl phosphate-water) at 200 – 350 °C. The thickness of iron phosphate thin films depends linearly on the ALD cycle, indicating their self-limiting growth behavior. The growth per cycle of iron phosphate thin films was determined to be ∼ 0.2, 0.4, 0.6, and 0.5 Å, at 200, 250, 300, and 350 °C, respectively. Characterization by SEM, TEM, and HRTEM techniques revealed uniform and conformal coating of amorphous iron phosphates on the surface of NCNTs. XANES analysis confirmed Fe O P bonding in the iron phosphates prepared by ALD. Furthermore, electrochemical measurement verified the high electrochemical activity of the amorphous iron phosphate as a cathode material in lithium-ion batteries. It is expected that the amorphous iron phosphate prepared by this facile and cost-effective ALD approach will find applications in the next generation of lithium-ion batteries and thin film batteries as either cathode materials or surface coating materials. [ABSTRACT FROM AUTHOR]

A polyethyleneimine (PEI)–iron phosphate (FePO 4 ) nanocomposite is prepared by immobilization of PEI onto the surface of FePO 4 nanoparticles via electrostatic interaction. The obtained PEI–FePO 4 nanocomposites are spherical with a size centered in ca. 100 nm. They provide a novel adsorbent for the solid-phase extraction of DNA from complex sample matrices. At pH 4, 50 μg mL −1 of DNA (salmon sperm DNA sodium salt) in 1.0 mL aqueous solution are quantitatively adsorbed (100%) by 2 mg of the PEI–FePO 4 nanocomposites, and meanwhile the coexisting albumin at a same concentration level is not retained, demonstrating the favorable selectivity of the nanocomposites to DNA against proteins. The adsorption behaviors of DNA onto the PEI–FePO 4 nanocomposites fit Langmuir model, corresponding to an adsorption capacity of 61.88 mg g −1 . The adsorbed DNA could be readily recovered by using a 0.04 mol L −1 Britton–Robinson (BR) buffer at pH 10, resulting in a recovery of 85%. The nanocomposites have been further used for the isolation of DNA from a series of real sample matrices, including synthetic λ-DNA sample, human whole blood and Escherichia coli cell lysate. The extraction efficiency and the purity of the recovered DNA are at least comparable to those achieved by using the reported sorbent materials or commercial kits. In addition, the DNAs isolated from human whole blood and E. coli cell lysate are of high quality, which have been further demonstrated by using them as templates for successful PCR amplifications. [ABSTRACT FROM AUTHOR]

Three kinds of bulk iron phosphates were prepared via different methods and employed as model catalysts in the oxy-bromination of methane (OBM). NaFe(PO) was obtained via a fluoride route for the first time that showed even superior catalytic performance than FePO. Phase evolution from NaFe(PO) to NaFe(PO) after the OBM was confirmed both by X-ray diffraction and Fe Mössbauer spectroscopy. Temperature-programmed reduction of hydrogen and desorption of CHBr revealed that the redox capacity of iron phosphates were responsible for the generation of bromine radicals on catalyst surfaces while CHBr-involved reactions likely belonged to gas-phase reactions. Graphical Abstract: Model iron phosphate catalysts were synthesized by three different methods. It was found that the NaFe(PO) catalyst prepared by a fluoride route showed superior OBM performance than the other two catalysts both with the phase of FePO, especially for producing higher CHBr selectivity.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: FePO4/graphene and LiFePO4/graphene hybrids have been synthesized by an eco-friendly RAAP-directed growth method. With this strategy, FePO4 and LiFePO4 particles have been grown on the exfoliated graphene-assembled scaffolds. Both of the hybrids present superior electrochemical properties, i.e., high rate capability combined with good capacity retention upon cycling, indicating the great potential as the cathode materials for Li-ion batteries. [Copyright &y& Elsevier]

Highlights: [•] Mesoporous iron phosphate is prepared by a cationic surfactant-assisted procedure. [•] Up to 30% of phosphonate units can enter the oxo-phosphate network in hybrid solids. [•] Pure and functionalized materials exhibit relatively high surface areas. [ABSTRACT FROM AUTHOR]

Abstract: Lithium-rich layered cathode Li1.2Mn0.54Ni0.13Co0.13O2 is synthesized by a co-precipitation method followed by high-temperature treatment and surface coated with different amount of amorphous FePO4. The microstructure and electrochemical performance of the as-prepared cathode materials are investigated systematically. It is demonstrated that the Li1.2Mn0.54Ni0.13Co0.13O2 particles are uniformly coated with amorphous FePO4. With proper amount of amorphous FePO4 coating layer, significant improvements in discharge capacity, initial Coulombic efficiency, rate capability, cycle performance, and thermal stability are achieved at room temperature. Specifically, the 3 wt.% FePO4-coated cathode exhibits the highest discharge specific capacities (271.7 mAh g−1 at C/20), improved initial Coulombic efficiency (85.1%), and best cyclability (discharge capacity of 202.6 mAh g−1 at C/2 after 100 cycles), while the 1 wt.% FePO4-coated cathode displays the best rate capability (194.3 mAh g−1 at 1 C rate and 167.9 mAh g−1 at 2 C rate). The charge–discharge curves and electrochemical impedance spectra reveal that the improved electrochemical performances are due to the suppression of both the oxygen vacancy elimination at the end of the first charge and side reactions of the cathode with the electrolyte, as well as the decrease in charge transfer polarization by the FePO4 coating layer. [Copyright &y& Elsevier]

Abstract: By using large mesoporous carbon (LMC) as a novel host matrix, LMC–FePO4 nanohybrid has been synthesized through a facile homogeneous precipitation process and subsequent annealing approach. When evaluated as a cathode for lithium-ion batteries (LIBs), the LMC–FePO4 nanohybrid exhibits higher specific capacities, improved rate capability, and better cycling performance by virtue of its unique structural characteristics. [Copyright &y& Elsevier]

Abstract: FePO4-SBA-15 (OP) was directly synthesized via a one-pot hydrothermal technique, using Fe(NO3)3 and H3PO4 as the precursors. FePO4/SBA-15 (IMP) was also prepared as a reference, using an impregnation method and commercially available SBA-15 as the support. The yielding samples were employed to catalyze the harsh oxy-bromination of methane (OBM) reaction, showing similar initial catalytic performances. The fresh and spent samples after catalytic reaction were thoroughly characterized by N2-physisoption, inductively coupled plasma, wide- and small-angle X-ray diffraction, transmission electron microscopy, diffuse reflectance UV–vis spectroscopy, temperature-programmed oxidation, and room temperature 57Fe Mössbauer spectroscopy. It was found that the FePO4 was in good crystalline in the OP sample while it was in amorphous for the IMP catalyst. Despite this difference, both FePO4 phases in the fresh samples were transformed into Fe7(PO4)6 and Fe2P2O7 in the spent ones. Furthermore, the OP catalyst showed excellent stability in a period of 1000h time-on-stream performance without apparent deposition of cokes. The losses of P and Fe after the catalytic evaluation were only 9.5% and 15.5%, respectively, while the ratio of P/Fe remained close to 1.0. N2-adsorption and TEM observations confirmed that the mesoporous pores were extremely stable under the harsh reaction ambience, which might play a crucial role in the stability test. [Copyright &y& Elsevier]

Abstract: The 2D channel mixed-valent iron (II/III) monophosphate SrFe3(PO4)3 was synthesized via one step mild hydrothermal method at 210°C and characterized by X-ray diffraction techniques and magnetization measurements. Coexistence of antiferromagnetic superexchange and ferromagnetic superexchange interactions was supposed to be in the lattice according to the Goodenough–Kanamori–Anderson rules. Temperature dependent DC magnetization measurement shows that SrFe3(PO4)3 is ferrimagnet with three magnetic transitions between 2 and 350K. Through AC magnetization measurement, re-entrant spin glass was observed due to the competition between ferromagnetic and antiferromagnetic interactions. Furthermore, an interesting field induced stepped magnetization was observed in SrFe3(PO4)3 at 2K with the saturation magnetization Ms=2.4μB/f.u. at 5T. [Copyright &y& Elsevier]

Abstract: Amorphous iron phosphate (FePO4) was investigated as a cathode material for battery applications using aqueous (lithium hydroxide or potassium hydroxide) electrolytes. Phosphate-based cathode materials are of great interest in lithium batteries which use non-aqueous electrolytes. In order for these materials to be used as cathodes in aqueous electrolytes it is important to understand their reduction/oxidation mechanisms. Potentiostatic and galvanostatic techniques are used to study these mechanisms. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) have been used to gain insight into the reduction/oxidation behavior of FePO4 cathodes. Our results show that FePO4 undergoes reversible Fe3+/2+ processes of reduction and oxidation in LiOH electrolyte, while using KOH electrolyte this process is found to be irreversible. The lithium intercalation mechanism is identified for LiOH while in the case of KOH electrolyte H reacts to form FeOOH. The Zn|LiOH|FePO4 battery provides a reversible capacity of 65mAh/g. The results indicate the trigonal FePO4 as an attractive host intercalation compound. [Copyright &y& Elsevier]

Single crystals of iron and manganese phosphate Fe 6.36Mn 0.64(PO 3(OH)) 4(PO 4) 2 was synthesized by hydrothermal method. The compound crystallizes in the Fe 7(PO 4) 6 structure type and is isotypic with the solid solution $$ {\text{M}}_{{7 - {\text{x}}}} {\text{M}}_{\text{x}}^{\prime} \left( {{\text{HPO}}_{4} } \right)_{4} \left( {{\text{PO}}_{4} } \right)_{2} $$ where M is Fe, Co, Mg, Mn. The compound is triclinic, P-1, a = 6.571(5), b = 7.993(3), c = 9.547(2) Ǻ, α = 103.97(1)°, β = 109.29(2)°, γ = 101.57(3)°. The structure is based on a three-dimensional framework of distorted edge-sharing MO 6 and MO 5 polyhedra, forming infinite chains, which are interlinked by corner-sharing with PO 4 tetrahedra. The formula unit is centrosymmetric, with all atoms in general positions except for one Fe atom, which has site symmetry −1. Graphical Abstract:: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Synthesis, single crystal X-ray diffraction, Mössbauer and magnetic studies of a new iron phosphate Rb9Fe7(PO4)10 are described. This compound crystallizes in the monoclinic system with the space group P21/a and the following parameters: a =9.886(4)Å, b =16.493(2)Å, c =13.437(2)Å, β =110.49(3)° and Z =2. Its structure is closely related to that of the Cs9−x K x Fe7(PO4)10 phosphates. The 3D framework consists of FeO6 and FeO5 polyhedra and Fe2O10 units of corner-sharing FeO6 and FeO5 polyhedra. These units are linked to each other by the phosphate tetrahedra in such a way that the resulting framework forms large intersecting tunnels extending along the a and c directions, where the Rb+ cations are located. A high temperature X-ray powder diffraction study showed a partial decomposition of the product above 773K. The magnetic susceptibility results are consistent with Fe(III) showing an antiferromagnetic ordering below T N ≈19K and a paramagnetic behavior in the range of 50–300K. The application of the Curie–Weiss law yields an effective moment of 5.99μB in a good agreement with the ideal spin only value of 5.92μB for d5-iron(III). The distribution of iron and its local environments were confirmed by a Mössbauer study undertaken at 293 and 4.2K. [Copyright &y& Elsevier]

Abstract: In situ FTIR spectroscopy coupled with downstream mass spectrometry has been used to clarify the pathways for room temperature (rt) CO oxidation over iron phosphate-supported Au catalyst. The charge state of Au on Au/FePO4 after calcination, reduction, or under reaction conditions was assessed by both FTIR spectroscopy (CO probing) and X-ray absorption near edge spectroscopy (XANES). Results from both approaches show that cationic gold species dominate the surface after pretreatment in O2 at 200°C. A portion of the cationic gold on Au/FePO4 can be reduced by the initial CO adsorption at rt, and subsequently repeated CO exposures do not reduce the remaining cationic Au. FTIR and Raman results from cycled CO reduction and O2 reoxidation of Au/FePO4 indicate that there are active structural oxygen species on the surface of Au/FePO4that can be consumed by CO and then replenished by gaseous O2 at rt. Au activates both CO and O2 so that the FePO4 support can undergo reduction (by CO) and reoxidation (by O2) cycles. The results of CO oxidation with labeled 18O2 suggest the operation of two parallel reaction pathways at rt: (1) a redox pathway in which FePO4 supplies active oxygen and (2) a direct pathway on metallic Au, via either Langmuir–Hinshelwood or Eley–Rideal mechanism, in which gas phase O2 provides the active oxygen. [Copyright &y& Elsevier]

Abstract: Iron phenyl phosphate (FePP) was synthesized from a mixture of FeCl3 and phenyl phosphate (C6H5PO4H2) in aqueous media. X-ray diffraction (XRD) pattern of the FePP exhibited a peak at 2θ =5.6° and a broad hump at 2θ =15–35°. The FePP was plate-like particles and gave rise to the lattice patterns having uniform alternating spacings of ca. 1.5nm and ca. 1.2nm. The chemical formula of FePP could be shown as Fe(OH)(C6H5PO4H)1.6(H2PO4)0.4·5.1H2O. These facts allow us to infer that the FePP was composed of a multilayer alternating bilayer of phenyl groups and amorphous iron phosphate phases. The synthetic FePP particle was aged at pH 6.0 and 85°C for different periods of 0–120h in aqueous media. Aging for 96h disappeared the FePP and formed monoclinic FePO4·2H2O. Further, the monoclinic FePO4·2H2O transformed in orthorhombic FePO4·2H2O by aging for 120h. The orthorhombic FePO4·2H2O was rod-shaped particles with the size of ca. 18nm in width and ca. 45nm in length and its specific surface area was 25m2 g−1. From these results, it can be presumed that the FePP is dissolved, hydrolyzed and reprecipitated to crystalline FePO4·2H2O. [Copyright &y& Elsevier]

SBA-15-supported iron phosphate (FePO4) has been characterized with XRD, TEM, Raman spectroscopy and H2-TPR, and studied for the partial oxidation of CH4 with O2. The characterizations suggest that the FePO4 species with loading amount lower than 40 wt.% are encapsulated within the mesoporous channels of SBA-15, and these species possibly exist as small FePO4 clusters with the local coordination environment of iron being similar to that in the crystalline FePO4. However, these encapsulated FePO4 clusters could be reduced at remarkably lower temperatures than the crystalline FePO4. The SBA-15-supported FePO4 catalysts exhibit higher CH4 conversion and HCHO selectivity than the unsupported and the MCM-41-supported ones in the partial oxidation of CH4 with O2. The catalyst with a loading amount of 5 wt.% shows the highest HCHO selectivity at a given CH4 conversion and the highest HCHO formation rate based on the amount of FePO4 in the catalyst. It is likely that the improved catalytic performances of the SBA-15-supported samples are related to the enhanced redox properties of FePO4 species, the large porous diameter and the high inertness of SBA-15. [Copyright &y& Elsevier]

The crystal structure of the synthetic iron phosphate Na0.10(1)Fe6.99(1)(P1.00(1)O4)6 has been refined at 270 and 100 K from single-crystal X-ray diffraction data. The compound is triclinic, P−1, Z=1, lattice parameters: a=6.3944(9) Å, b=7.956(1) Å, c=9.364(1) Å, α=105.13(1)°, β=108.35(1)°, γ=101.64(1)° at 270 K and adopts the well-known howardevansite structure type. Iron, being both in the divalent and the trivalent valence state, is ordered on the four symmetry non-equivalent iron positions [Fe2+ on Fe(1) and Fe(3), Fe3+ on Fe(2) and Fe(4)]. Three of the four iron positions show octahedral oxygen atom coordination, the fourth one, which is occupied by Fe2+, is five-fold coordinated. The structure consists of crankshafts (buckled chains) of edge sharing Fe-oxygen polyhedra, passing through the unit cell in [101] direction. Structural investigation at 100 K shows no change of symmetry. The valence state and distribution of iron was determined by 57Fe Mössbauer spectroscopy. The compound shows 4 subspectra in agreement with the four different Fe sites. The assignment of the Fe2+ doublets to the Fe(1) and Fe(3) sites is trivial due to the 2:1 stoichiometry, also found in the Mössbauer spectra. For the Fe3+ sites, the temperature-dependent variation of structural distortion parameters and the quadrupole splitting led to a clear doublet assignment. [Copyright &y& Elsevier]

Iron phosphate catalysts possess a unique selectivity to oxidative dehydrogenation. Unlike ordinary catalysts consisting of molybdenum and/or vanadium, they have no double-bond oxygen species (M&z.dbnd6;O) that are considered to be responsible for the oxygen insertion function and, as a result, for the degradation by C–C bond fission. The defect of iron phosphate catalysts is a lack of oxidation activity. Addition of a very small amount of molybdenum into iron phosphate enhances markedly the oxidation activity without modifying the high selectivity originated from iron phosphate. The marked increase in the activity is ascribable to an increase in the reducibility of iron phosphate, because the reoxidizability of iron phosphate is high enough. It is proposed that the reaction over a Mo-doped iron phosphate is promoted by redox cycle of iron phosphate but not by that of molybdenum phosphate. [Copyright &y& Elsevier]

Iron phosphate supported on MCM-41 has been studied for partial oxidation of methane with both oxygen and nitrous oxide. Characterizations with XRD, Raman spectroscopy, XPS, and H2-TPR suggest that the supported iron phosphate species with loading amounts lower than 40 wt% are located and dispersed in the mesopores of MCM-41. Such iron phosphate species can be reduced more readily than the unsupported iron phosphate at lower temperatures. Methane is selectively converted to methanol, formaldehyde, and dimethyl ether over the supported and the unsupported iron phosphate with nitrous oxide at milder temperatures (300–500 °C), while formaldehyde is mainly produced along with carbon oxides with oxygen at relatively higher temperatures (400–600 °C). The supporting of iron phosphate onto MCM-41 with loading amounts of ca. 20–40 wt% increases both methane conversion and overall selectivity to useful oxygenates with either oxygen or nitrous oxide. Kinetic studies indicate that the activation of oxygen occurs rapidly, while the activation of nitrous oxide proceeds at a comparable rate with the conversion of methane by the active oxygen species over both the supported and the unsupported catalysts. The supported catalyst, however, enhances the activation of nitrous oxide and thus remarkably inhibits the carbon deposition occurring over the unsupported iron phosphate. [Copyright &y& Elsevier]

Fe4(P2O7)3 was prepared from Fe(PO3)3 and FePO4 at 940°C under oxygen. The unit cell is monoclinic, space group P21/n, with a=7.389(2) A˚, b=21.337(1) A˚, c=9.517(2) A˚, β=90(1)°, and Z=4. The crystallographic structure has been determined from a single crystal through direct methods and difference Fourier synthesis and refined to R=0.10 (Rw=0.09). The three-dimensional framework is built up from Fe2O9 clusters of two face-sharing octahedra, linked by bent diphosphates P2O7 (P–O–P∼156°). Fe4(P2O7)3 is antiferromagnetic below TN=50 K. The magnetic structure has been determinated by means of powder neutron diffraction. There are four antiferromagnetic iron sublattices corresponding to the four crystallographically distinct iron atoms. The magnetic moments are antiferromagnetically coupled inside the Fe2O9 dimers, in agreement with the Goodenough rules. They are parallel to the c axis and have 4.55(5) μB value at 1.7 K. The magnetic interactions are discussed. Mo¨ssbauer spectra are fitted with four doublets and sextuplets in the paramagnetic and antiferromagnetic states, respectively. Their rather high isomer shifts are explained by the inductive effect. [Copyright &y& Elsevier]