X-ray Absorption Near Edge Structure Results Research Articles

Tissue-variation of iron stable isotopes in marine fish coupled with speciation analysis using X-ray absorption fine structure

The Fe stable isotope ratio (δ56Fe) in tissues is a potential parameter for examining the Fe metabolism in marine fish. Although the effect of ferritin storage has been proposed as a possible cause of heavy isotope (56Fe) enrichment in the liver, no speciation and stable isotope ratio coupling data are available. Here, we report the δ56Fe values measured by multicollector ICP-MS and the result of Fe K-edge X-ray absorption near-edge structure (XANES) analysis of multiple tissues obtained from a skipjack tuna (Katsuwonus pelamis) and a chub mackerel (Scomber japonicus). Apparent isotopic fractionation between the liver and the muscle samples (Δ56FeL–M = δ56Feliver − δ56Femuscle) from these species was observed (0.85 ‰ and 0.57 ‰, respectively). The dominant Fe species in the muscle was heme Fe (the sum of methemoglobin, oxyhemoglobin, and deoxyhemoglobin), while ferritin was not detected according to the linear combination fitting of the XANES spectra. In the liver, ferritin contribution was ca. 28 %–54 % of the total Fe content. The apparent difference in δ56Fe between heme Fe and ferritin was estimated to range from 1.41 ‰ to 1.52 ‰ based on the tissue-specific δ56Fe values and the XANES results. These results indicate that the Fe storage as ferritin does not induce the lowering of δ56Fe in the muscle, considering the low contribution of the liver Fe to the total Fe content in the body.

X‐ray Absorption Spectroscopy for the Characterization of Photoinduced Linkage Isomers in Single Crystals: Experimental Setup and XANES Results**

AbstractPhotoinduced linkage isomers (PLI) of the nitrosyl ligand in single crystals of Na2[Fe(CN)5NO] ⋅ 2H2O (SNP, sodium nitroprusside) have been studied by X‐ray absorption spectroscopy (XAS) at low temperatures, using a cryostat allowing in‐situ polarized LASER irradiation and XAS measurements. In the XANES (X‐ray absorption near edge structure) region a significant modification of the pre‐edge peak intensities is observed after irradiation of the ground state (GS) nitrosyl NO‐κN isomer with light in the blue and infrared spectral range, used for the generation of the isonitrosyl NO‐κO isomer (MS1) and the side‐on bound κ2N,O isomer (MS2), respectively. These observations are interpreted with respect to the changes in the nature of the frontier (unoccupied) molecular orbitals of the different linkage isomer configurations, expected from earlier calculations.

Quantitative determination of nickel speciation for the presence of free oxide in commercial fluid catalytic cracking catalysts

Motivated by the potential over-catalysis and hazardousness of free nickel oxide (NiO) in the equilibrated catalysts (Ecats) collected from fluid catalytic cracking (FCC) refineries, this study aims to establish a simple bulk method, namely chemical leaching method to rapidly quantify the NiO content within thirteen commercial Ecats collected from different units. The synchrotron-–based, X–ray absorption near–edge structure (XANES) was performed to assess the validity of this method, as well as to examine the coordination structure of Ni by the extended X–ray absorption fine structure (EXAFS) analysis. Additionally, thermodynamics calculation was attempted to validate the affiliation of Ni with other metal oxides. The optimum leaching condition was validated as 60 °C in 60 min using 1 M sulfuric acid. Accordingly, the NiO was determined to reach 70–439 ppm in all Ecats, which warrants a non–hazardousness of these samples. Additionally, for the Ecats with a remarkably higher Ni content, the XANES results are biased by the enrichment of NiO on the catalyst surface. The majority of Ni was found to affiliate with Al in the form of aluminate, with the remaining 11%–15% Ni passivated effectively by lanthanum (La). The oxygen–rich regeneration condition could be beneficial for promoting the affiliation of Ni by La.

Spectroscopic study on the local structure of sulfate (SO42−) incorporated in scorodite (FeAsO4·2H2O) lattice: Implications for understanding the Fe(III)-As(V)-SO42−-bearing minerals formation

AbstractThe incorporation of sulfate (SO42−) into the scorodite (FeAsO4·2H2O) lattice is an important mechanism during arsenic (As) fixation in natural and engineered settings. However, spectroscopic evidence of SO42− speciation and local structure in scorodite lattice is still lacking. In this study, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), sulfur K-edge X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopic analyses in combination with density functional theory (DFT) calculations were used to determine the local coordination environment of SO42− in the naturally and hydrothermally synthesized scorodite. The SO42− retention in natural scorodite and the effect of pH value and initial Na+ concentration on the incorporation of SO42− in synthetic scorodite were investigated. The results showed that trace amounts of SO42− were incorporated in natural scorodite samples. Scanning electron microscopy (SEM) results revealed that SO42− was homogeneously distributed inside the natural and synthetic scorodite particles, and its content in the synthetic scorodite increased slightly with the initial Na+ concentration at pH of 1.2 and 1.8. The FTIR features and XANES results indicated that the coordination number (CN) of FeO6 octahedra around SO42− in scorodite lattice is four. The DFT calculation optimized interatomic distances of S-O were 1.45, 1.46, 1.48, and 1.48 Å with an average of ~1.47 Å, and the interatomic distances of S-Fe were 3.29, 3.29, 3.33, and 3.41 Å with an average of ~3.33 Å. EXAFS analysis gave an average S-O bond length of 1.47(1) and S-Fe bond length of 3.33(1) Å with a CNS-Fe = 4 for SO42− in the scorodite structure, in good agreement with the DFT optimized structure. The results conclusively showed that SO42− in the scorodite lattice may be in the form of a Fe2(SO4)3-like local structure. The present study is significant for understanding the formation mechanism of scorodite in natural environments and hydrometallurgical unit operations for waste sulfuric acid treatment.

Arsenate removal by resin-supported ferric ions: Mechanism, modeling, and column study

Removal of 10 mg/dm3 of As(V) by resin-supported Fe(III) was investigated in batch and column studies. The best As(V) removal was achieved at pH 3, and a high sorption density of 0.40 mmol-As/mmol-Fe was obtained after 96 h in a batch study. This sorption density could not be explained only by As(V) surface complexation with ferrihydrite. X-ray absorption near edge structure (XANES) analysis at the As K-edge suggested that over 90% of the As(V) was removed by surface precipitation as poorly crystalline ferric arsenate and the remainder was removed by surface complexation with ferrihydrite. XANES analysis at Fe K-edge suggested that 14%–35% of Fe(III) in the resin was used in the ferrihydrite and ferric arsenate. Kinetic modeling of the precipitation of ferrihydrite and ferric arsenate combined with a surface complexation model for As(V) and ferrihydrite successfully reproduced the batch experiment results. The kinetic constant for precipitation of ferrihydrite and ferric arsenate obtained by fitting of the batch experiment results successfully reproduced the column experiment results. The ratio of surface precipitation of ferric arsenate and As(V) surface complexation with ferrihydrite obtained by the constructed model was the same as in the XANES results. In the column study, a slow flow was advantageous for As(V) removal because surface precipitation of ferric arsenate took a long time.

Structural, electronic, and electrical behaviour of MWCNTs: TiO2 (:SiO2) nanocomposites

We have functionalized multiwall carbon nanotubes (MWCNTs) with the composition of SiO2 and TiO2 (MWCNTs:TiO2:SiO2) at different Ti:Si stoichiometric ratios (Ti:Si ≈ 6:6 at% and ≈10:10 at%) using the hydrothermal process. The micro-structural, electronic and electrical properties of the unfunctionalized and functionalized MWCNTs were studied. Changes in surface morphology, degree of hybridization, crystallite structure and bonding structure due to functionalization were studied using field-emission scanning electron microscopy, Raman spectroscopy, x-ray diffraction, x-ray photoemission spectroscopy (XPS) and x-ray absorption near edge structure (XANES) spectroscopy techniques. Memristive and charge storage properties for MWCNTs:TiO2:SiO2 nanocomposites (NCs) are more pronounced on NCs functionalised with high stoichiometric ratio (Ti:Si ≈ 10:10) due to the contribution of Ti3+ and Si 2p core states as indicated by XPS and XANES results. The tunability of electrical conductivity is shown by an increase in the measured current and semiconducting I–V behaviour of the material as a result of high content of Ti-charge transfer. These observed changes in the electrical behaviour and electronic/bonding structure of the NCs indicate that the material could be useful for electrical/electronic applications and photocatalytic activity.

Hydroponic growth test of maize sprouts to evaluate As, Cd, Cr and Pb translocation from mineral fertilizer and As and Cr speciation

The present study proposes a maize sprouts hydroponic growth model to evaluate the As, Cd, Cr and Pb translocation from multinutrient fertilizer and to do speciation of As and Cr in this fertilizer and As in parts of plant in order to predict their phytoavailability. X-ray absorption near edge structure (XANES) was employed to speciate As and Cr directly on fertilizer solid sample. Arsenate (AsV) and a solid solution of FeCrO3 were the major species identified in the samples. The sprouts were hydroponically cultivated in water, fertilizer slurry and fertilizer extract media. Concentrations of As, Cd and Pb measured on leaves of maize sprouts ranged from 0.061 to 0.31 mg kg−1, whereas Cr was not translocated to the aerial parts of sprouts. High performance liquid chromatographic with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) analysis was used to determine As speciation in maize sprouts, as well as in the fertilizer extracts and slurries. Arsenate was the only species identified in the initial fertilizer extract and this information is in agreement with the XANES results. However, the reduction of arsenate to arsenite was observed in extracts and slurries collected after sprout growth, probably due to the action of exudates secreted by plant roots. Arsenite was the predominant species identified in sprouts, the high phosphate concentration in the medium may have contributed to reduce arsenate phytoavailability.

Bioleaching of chalcopyrite with different crystal phases by Acidianus manzaensis

Abstract Bioleaching of chalcopyrite with different crystal structures (α-phase, β-phase and γ-phase) by Acidianus manzaensis was comparatively studied by synchrotron radiation based X-ray diffraction (SR-XRD) and S K-edge X-ray absorption near edge structure (XANES) spectroscopy. The α-phase, β-phase and γ-phase chalcopyrite was prepared by heating original chalcopyrite at 583, 773 and 848 K, respectively. Bioleaching results showed that [Cu2+] in the leaching solution of α-phase, β-phase, γ-phase and original chalcopyrite after 10 days of bioleaching was 1.27, 1.86, 1.43 and 1.13 g/L, respectively, suggesting that β-phase had a better leaching kinetics than others. SR-XRD and XANES results indicated that jarosite and chalcopyrite were the main components in the leaching residues in all cases, and elemental sulfur formed in the early stage of bioleaching. While for β-phase and γ-phase chalcopyrite during bioleaching, bornite was produced in the initial stage of leaching, and turned into chalcocite on day 6.

Dielectric, ferroelectric, and piezoelectric properties of lead-free Ba0.95Ca0.05Ti1-xZrxO3 ceramics

Ba0.95Ca0.05Ti1-xZrxO3 (BCTZO) ceramics were prepared by a solid state reaction method. The samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray absorption near edge structure (XANES). The ceramics exhibit a pure perovskite structure. The average grain size gradually decreases with increasing Zr concentration. XANES results indicate that the intensities of pre-edge peaks dropped with increasing Zr concentration. The BCTZO ceramic of x = 0.05 has the optimum electrical properties with the maximum dielectric constant (ε'm), remanent polarization (2Pr), coercive electric field (2Ec) and piezoelectric charge constant (d33) of 7,244, 12.54 (μC/cm2), 5.29 (kV/cm) and 288 (pC/N), respectively.

Distributions and Leaching Behaviors of Toxic Elements in Fly Ash.

Fly ash usually contains a considerable amount of toxic elements that can be leached into the environment, thereby easily leading to serious contaminations. In this work, the leaching behaviors of poisonous elements including boron (B), phosphorus (P), vanadium (V), chromium (Cr), arsenic (As), selenium (Se), molybdenum (Mo), antimony (Sb), and tungsten (W) from fly ash were explored by sequential extraction. Importantly, the associations of these elements in fly ash were discussed based on their leaching and X-ray absorption near-edge structure (XANES) results. From the XANES results, it was observed that V(IV), Cr(III), As(V), Se(IV), and W(IV) were their main states of existence in fly ash. In terms of leaching results, large amounts of Mo and W were leached into pure water, which indicated their high mobilities. Furthermore, the occurrence of Mo in fly ash was mainly in the form of oxides, and W had complex associations including WX4 (X can be monovalent anions), its reduction state or association with the elements that can be oxidized, and existence in silicates. B was as easily released into the environment as Mo and W. It can have several associations with the other cations, such as Ca2+, Na+, and Mg2+, and occurs in silicates. In contrast, most of the Cr and Sb were locked in silicates, indicating that they were very stable in fly ash. In addition, P, V, and As can exist within the structure of silicates as well. However, a considerable amount of them leached in the reduction step with a low pH. Hence, they can be associated with Ca2+, Na+, Mg2+, or Fe3+. In terms of Se, oxidation processes played an important role in controlling its leaching because of the oxidation of Se(IV) to Se(VI). Calcium selenite should be the predominant form of Se in fly ash.

X-ray absorption spectroscopy investigation of relationship between Mg vacancy and magnetic properties of MgO powder

This paper reports on the ferromagnetism of MgO powder and degraded powder at room temperature. The starting material, Mg(OH)2, was analyzed by X-ray fluorescence (XRF) spectrometry and then calcined at 450 °C for 5 h to obtain fresh MgO powder. The calcined powder was separated into two batches (i) kept in vacuum sealed (MgO-F) and (ii) kept at ambient environment (30–32 °C at 45–55% relative humidity) for 2 days (MgO-D). The samples were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and X-ray absorption spectroscopy (XAS) including X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). XRD and EXAFS confirmed that MgO phase in MgO-F. Both Mg(OH)2 and MgO compositions were found in MgO-D. The origin of ferromagnetism at room temperature of MgO-F and MgO-D is attributed to the Mg vacancies in the MgO structure that revealed and verified by XANES and EXAFS results.

Influence of Ni doping on PtNi nanoparticles: Synthesis, electronic/atomic structure and photocatalyst investigations

Carbon-supported Pt and PtNi nanoparticles (NPs) were synthesized using a borohydride reduction method. Structural properties were studied by synchrotron X-ray diffraction (XRD) and the size/shape of the NPs was determined by transmission electron microscope (TEM). X-ray absorption spectroscopy with its two amendments; X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), has been employed to investigate the local electronic/atomic structure surrounding the Pt and Ni atoms. XANES results, at Pt L3-edge and Ni K-edge, have shown fractional oxidation of Pt and Ni atoms. The Pt3Ni1NPs have exhibited a lower bond distance of Pt–Ni shell and higher coordination number of Pt–Ni shells, indicating the alloy formation between Pt and Ni. We further have demonstrated that the Pt and PtNi NPs can serve as effective photocatalysts towards the degradation of water pollutant dye (methyl orange (MO)). By considering the interband charge-transfer of Pt (5d →6sp), a tentative mechanism is proposed to understand the photocatalytic degradation of MO dye molecules by Pt/PtNi NPs under the light irradiation.

Effect of electric field on local structure of PZT single crystal studied by X-ray absorption spectroscopy technique

ABSTRACTThe aim of this work is to investigate the local structure of PbZr1−xTixO3 (PZT) single crystal with x = 0.44 under the application of electric field employing Synchrotron X-ray Absorption Near-Edge Structure (XANES) technique. In this experiment, PZT single crystal was subjected to 0.35 kV/mm and 0.70 kV/mm electric fields. The Ti K-edge XANES spectra reflect the significant change of the local structure of PZT unit cell before and after static electrical loading. From the XANES results, it was clearly seen that XANES spectral intensity gradually changed when the electrical load was applied. This can be caused by the shift of Ti atoms in the unit cell. The clear agreement between the measured and simulated XANES spectra was the supporting evidence of Ti off-center displacement in the PZT unit cell.

Facile synthesis and spectroscopic characterization of fluorinated graphene with tunable C/F ratio via Zn reduction

A facile approach has been developed to synthesize fluorinated graphene (FG) nanosheets with tunable C/F ratio through liquid-phase exfoliation of fluorinated graphite (FGi) in N-methyl-2-pyrrolidone (NMP) and subsequent reduction with Zn powder. The evolution of surface composition and electronic structure of FG is investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge structure (XANES) spectroscopy and Raman spectroscopy. It is shown that the C/F atomic ratio of FG can be easily varied by Zn reduction with different reaction time and addition of diluted HCl solution. Both XPS and XANES results indicate the effective removal of covalent CF bonds and progressive restoration of sp2-hybridized structure upon the treatment of FG with Zn. Raman measurements further reveal that Zn reduction can effectively restore the π-electron conjugated electronic structure and reduce the optical gap of FG. This study provides a simple and effective route to tailor the surface composition and electronic structure of FG for potential applications.

Spectroscopic study of X-ray absorption near-edge structure of chemical states of Pt catalyst during growth of single-walled carbon nanotubes

Growth of single-walled carbon nanotubes (SWCNTs) by alcohol catalytic chemical vapor deposition with the assistance of Pt as a catalyst is a useful technique because small-diameter SWCNTs are prepared under low ethanol pressure. In the study reported here, we carried out spectroscopy of X-ray absorption near-edge structure (XANES) to investigate the chemical bonding states of the Pt catalyst during SWCNT growth. Pt L3-edge XANES spectra of the Pt catalyst showed that it was reduced during pre-heating and remained metallic during SWCNT growth. This indicates that carbon atoms dissociated from the ethanol molecules did not dissolve into the Pt catalyst particles, but diffused on their surface and formed SWCNTs. Based on the XANES results, a model of Pt-catalyzed SWCNT growth is proposed.

Composition of organic sulfur in riverine and marine sediments: Insights from sulfur stable isotopes and XANES spectroscopy

Sulfur isotopes and X-ray absorption near edge structure (XANES) spectroscopy were combined to characterize/compare three operational organic sulfur (OS) pools, i.e. fulvic acid sulfur (FA-S), humic acid sulfur (HA-S) and non-chromium reducible organic sulfur (non-CROS) in marine [the East China Sea (ECS) and Jiaozhou Bay (JZB)] vs. riverine [Yangtze River (YR) and JZB tributaries] sediments. XANES results indicate that in marine sediments high valency S was the dominant OS functionality in both HA-S and FA-S, while non-CROS was dominated by low valency OS (80–92%). In the riverine sediments FA-S was dominated by high valency OS, while the average fractions of low and high valency OS in HA-S were comparable. The isotopic composition of FA-S (δ34SFA-S) and HA-S (δ34SHA-S) indicated that a substantial fraction of sulfide was incorporated into FA via sulfurization in the marine sediments, whereas terrigenous OS was almost the sole important source of HA-S. Compared with the ECS sediments, JZB sediments had more depleted 34SFA-S and a higher fraction of highly reduced FA-S due to eutrophication induced sulfurization. Relative to riverine FA-S, substantial sulfurization had not resulted in an increase in the fraction of highly reduced FA-S in marine sediments. This implies that the terrestrial systems may be much more favorable for the formation and/or preservation of highly reduced biogenic FA-S than the marine settings. The fraction of highly reduced HA-S in the JZB and its tributaries was similar, whereas the fraction was much lower in the ECS than in the YR. This indicates that highly reduced HA-S moieties in the YR may have been subject to extensive mineralization loss during transport in the large riverine/estuarine system, whereas the process in the JZB tributaries may be much weakened due to a relatively small catchment area. Distinct differences in isotopic and structural composition between humic-S (FA-S+HA-S) and non-CROS in the ECS sediments indicate that a combination of S isotopes and S-XANES is needed for characterizing the two operational pools for a better understanding the nature of OS in the ocean.

Effects of strain relaxation in Pr0.67Sr0.33MnO3 films probed by polarization dependent X-ray absorption near edge structure.

The Mn K edge X-ray absorption near edge structure (XANES) of Pr0.67Sr0.33MnO3 films with different thicknesses on (001) LaAlO3 substrate was measured, and the effects of strain relaxation on film properties were investigated. The films showed in-plane compressive and out-of-plane tensile strains. Strain relaxation occurred with increasing film thickness, affecting both lattice constant and MnO6 octahedral rotation. In polarization dependent XANES measurements using in-plane (parallel) and out-of-plane (perpendicular) geometries, the different values of absorption resonance energy Er confirmed the film anisotropy. The values of Er along these two directions shifted towards each other with increasing film thickness. Correlating with X-ray diffraction (XRD) results it is suggested that the strain relaxation decreased the local anisotropy and corresponding probability of electronic charge transfer between Mn 3d and O 2p orbitals along the in-plane and out-of-plane directions. The XANES results were used to explain the film-thickness dependent magnetic and transport properties.

Determination of the local structure of CsBi4-xPbxTe6 (x = 0, 0.5) by X-ray absorption spectroscopy.

We have studied the local structure and valence electronic unoccupied states of thermoelectric CsBi4Te6 and superconducting CsBi3.5Pb0.5Te6 (Tc ∼ 3 K) by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) measurements. The Bi-L3 edge EXAFS reveals wide Bi-Te distance distribution for both compounds indicating complex atomic arrangements in the studied system. The mean square relative displacements (MSRDs) of the Bi-Te bond distances appear largely increased in Pb substituted system due to larger overall local disorder, however, one of the Bi-Te bonds shows a reduced disorder. On the other hand, the Bi-L3 edge XANES is hardly affected by Pb substitution while the Te-L1 edge XANES reveals increased density of unoccupied Te 5p states. This suggests that the carriers introduced by the Pb substitution in CsBi4-xPbxTe6 preferentially goes on Te sites. Similarly, the Cs-L3 edge XANES also shows small changes due to Pb-substitution and reduced local disorder indicated by the reduced width of the Cs-L3 edge white line. We have also shown that the X-ray photoemission spectroscopy (XPS) measurements on various electronic core levels are in a qualitative agreement with the XANES results. These findings are consistent with carrier doping and a reduced disorder in one direction to be likely factors to drive the thermoelectric CsBi4Te6 into a bulk superconductor by Pb-substitution in CsBi4-xPbxTe6.

Thermoelectric property and x-ray absorption near edge structure studies on Si-doped CaMnO3−δ

We report electrical resistivity, thermopower and Ca K-, Mn L2,3- and O K-edges x-ray absorption near edge structure (XANES) studies on CaMn1−xSixO3−δ with x=0, 0.02, and 0.05. The transport properties measurements indicate that the sample of x=0.02 has the lowest electrical resistivity compared to the samples of x=0 and 0.05. Meanwhile, the temperature dependence of thermopower behaves significantly different for samples of x=0.02 and 0.05. These unusual phenomena are elucidated based on the charge transfer equilibrium principle together with the XANES results, which show that the Si substitution for Mn appears to generate an electron doping effect and lattice distortion. Among the samples, CaMn0.98Si0.02O3−δ exhibits the highest figure of merit of 0.0128 at 300K. This value represents an improvement of about 52% compared to pristine CaMnO3−δ.

Non-platinum nanocatalyst on porous nitrogen-doped carbon fabricated by cathodic vacuum arc plasma technique

Polymer electrolyte membrane fuel cells (PEMFCs) convert chemical energy directly into electrical energy where catalysts composing of non-noble transition metals, nitrogen, and carbon compounds are the most promising materials to replace the expensive platinum catalysts for oxygen reduction reaction (ORR). In this research, cathodic vacuum arc plasma (CVAP) technique was used to fabricate porous nitrogen doped carbon (NC) and non-platinum catalyst on porous NC (Fe–NC) directly on ion exchange membrane for being used as an ORR catalyst at the cathode. The porous NC layer was fabricated on silicon wafer at 0.05mTorr, 0.1mTorr, 0.5mTorr, 1mTorr, and 5mTorr of nitrogen gas inlet. The AFM, and SEM images are observed to be regularly big with quite high hillocks and thin NC layers; these results indicate that the optimum process pressure of nitrogen gas inlet is 5mTorr for porous NC fabrication. The SEM–EDS detects Fe, N, and C elements in the prepared catalysts, and the XRD pattern reviews the iron nitride and the carbon nitride phases. The SEM images in the backscattered electron mode (BSE) reveal good dispersion of very small metal particles (bright spots) on the highly porous coral-like carbon film. The TEM images clearly show the spherical Fe nanoparticles (64nm) dispersed on the porous carbon film. However, the XANES (X-ray absorption near edge structure) analysis specifies that the prepared Fe is in the form of iron(III). As a result of no FeN standard for confirmation, both the XRD and the XANES results are used to confirm the Fe(III) compound. In preparing the catalyst as FeN, all these results specify that the CVAP technique can be used to produce the catalyst on the membrane.