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Zn-Doped FeO Nanosheets Formation Induced by EDA with High Magnetization and Investigation on the Formation Mechanism Jie Zhu, and Zhaodong Nan J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.7b02084 • Publication Date (Web): 19 Apr 2017 Downloaded from http://pubs.acs.org on April 23, 2017

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The Journal of Physical Chemistry

Zn-doped Fe3O4 Nanosheets Formation Induced by EDA with High Magnetization and Investigation on the Formation Mechanism Jie Zhu and Zhaodong Nan* College of Chemistry and Chemical Engineering, Yang Zhou University, 225002 Yangzhou, People’s Republic of China

Corresponding Authors E-mail: [email protected]. Tel: +86-514-87959896. Fax: +86-514-87959896. (Z.N.)

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ABSTRACT: Ethylenediamine (EDA) was always used as an additive to modify nanomaterials formation. However, the effect of EDA on the nanomaterials formation process has not been studied in detail. In the present study, Zn-doped Fe3O4 magnetic nanosheets with high magnetization and surface area were synthesized by a facile one-step solvothermal method, where EDA was added into the reaction system. The formation mechanism was firstly studied in details by using an in-situ calorimetric method. Compared with Zn-doped Fe3O4 clusters synthesized by the same method without EDA, the complexes formation, as [Fe(EDA)3]3+ and [Zn(EDA)3]2+, prevented alkoxides (Fe2(C2H4O2)3 and ZnC2H4O2) formation, and resulted in some reactions to occur at higher temperature. At the same time, the (111) facets of the Zn-doped Fe3O4 became stable, which resulted in the nanosheets formation. And the effect of the EDA on magnetization of the sample can be explained by the Zn2+ distributions at the tetrahedral (A-site) and octahedral (B-site) sites. These results demonstrated further that the EDA can change the Zn-doped Fe3O4 formation mechanism, which is not reported before as we know. Keywords:

Zinc

ferrite;

Ethylenediamine;

In-situ

nanomaterials.

2


caloriometry;

Magnetic

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1. Introduction Magnetic nanoparticles have received more attention in the past decades. Among these magnetic nanoparticles, ferrite magnetic nanoparticles have been extensively investigated owing to their wide use in different fields,1-5 in which fabrication of monodisperse nanoparticles with high magnetization and surface area simultaneously is critical for the application.6 Nanosized magnetic materials usually show a low magnetization value because of small particles, which limits their practical applications. The magnetization can be enhanced through increasing particles size,7, 8 which usually induces a superparamagnetic–ferrimagnetic transition. Zinc is one of the commonly used metal dopants into Fe3O4 due to its nonmagnetic property. Zn ferrite is an important spinel ferrite with excellent physical properties, and its properties are crucially determined by the size, morphology and cations distribution.9 A series of Zn ferrite nanoparticles were synthesized by using a chemical coprecipitated technique, in which Zn0.2Fe2.8O4 showed a maximum saturation magnetization of 80.93 emu/g.10 EDA has been considered to as one of additives to modify the morphology and magnetic property of ferrites. The fabrication of functional nanoparticles with controllable size and shape is of great importance for their fundamental scientific significance and broad technological applications.11,

12

Ding et al. successfully

synthesized Fe3O4 nanorods using EDA, which exhibited ferromagnetic behavior at room temperature with a magnetic saturation value of 72.94 emu/g.13 Hollow spheres of Fe3O4 were synthesized with EDA, which show a high saturation magnetization of 3



ca. 68 emu/g.14 The action of EDA was always reported as similar as a surfactant to stable nucleation and some facets of samples. However, no result has not been reported how to change materials formation mechanism with EDA in detail as far as we know. In our previous experiment, a series of Zn-doped ferrites was synthesized with cluster-shaped morphology for enhancing the magnetization.15-17 In the present study, EDA was added into the reaction systems. Compared with the Zn-doped Fe3O4 synthesized without EDA, the morphology of the as-prepared sample changed significantly from cluster to monodispersed nanosheets, and the magnetization was obviously enhanced. At the same time, the as-prepared sample showed higher BET surface area (80.6 m2/g), which can be widely used in different fields. Thus, it is very interested to study the ferrite formation with EDA. The formation mechanism of the nanosheets-shaped ferrite was studied in details by in situ calorimetry. The results demonstrated that EDA induced the (111) facet of the sample to be stable, and changed significantly the Zn-doped Fe3O4 magnetic nanosheets formation mechanism.

2. EXPERIMENTAL SECTION Materials. All chemicals in this work, such as ferric nitrate nonahydrate (Fe(NO3)3∙9H2O), zinc nitrate hexahydrate (Zn(NO3)2∙6H2O), ethylene glycol (C2H6O2), sodium ethoxide (C2H5ONa) and ethylenediamine (C2H8N2) were analytical grade regents from the Sinopharm Chemical Reagent Company and used as starting materials without further purification. 4


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Synthesis of Zn-doped Fe3O4 magnetic nanosheets. In a typical experiment, 0.60 mmol Zn(NO3)2∙6H2O and 8.4 mmol (Fe(NO3)3∙9H2O) were dissolved in 25 mL of anhydrous ethylene glycol, which the molar ratio of Zn2+ to Fe3+ was 1/14. Then, 9.0 mmol CH3COONa was added into the solution. The whole mixture was stirred vigorously to give a homogeneous solution, followed by the addition of ethylenediamine (EDA) with different molar amounts. Subsequently, the solution was transferred into a 50 mL teflon-lined stainless steel autoclave, which was thermally treated for 24 hours at 200 oC and then naturally cooled to room temperature. The final product was obtained by washing the precipitate a few times with distilled water and ethanol before being dried in a vacuum oven at 50 oC for 24 hours. Different samples named as E5, E8, E10, E15 and E20 were synthesized with 45, 72, 90, 135, and 180 mmol of EDA, respectively, which 5, 8, 10, 15 and 20 represent molar ratio of EDA to metal ions (9.0 mmol of Zn2+ and Fe3+). Characterization. X-ray powder diffraction (XRD) measurements were performed on a Bruker D8 Advance X-ray diffractometer with Cu Ka radiation (l = 1.5418 Å). The 2θ range used in the measurement was from 10 to 80 o. Standard and high-resolution transmission electron microscopy (TEM and HRTEM) measurements were performed on a JEOL-2010 TEM at an acceleration voltage of 200 kV. Samples were first ultrasonically dispersed in absolute alcohol and dropcast onto copper grids. Infrared spectrum (FT-IR) measurements were performed on a Nicolet Aexus 470, with scanning from 4000 to 400 cm-1 by using KBr pellets under ambient temperature. The metal ion concentration was measured by inductively coupled plasma atomic 5



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emission spectroscopy (ICP-AES) on an Optima 7300 DV (PerkinElmer). The chemical composition of the sample was determined by the dissolution of 0.2200 g of the sample in 10 mL of 28 wt% HCl solution, followed by the diluting it to 1000 mL. X-ray photoelectron spectroscopy (XPS) measurements were performed using a Thermo VG Thermo Scientific Escalab 250 fitted with a monochromatized X-ray Al Ka (1486.8 eV) source. A 150 W X-ray spot of 500mm in diameter was used for survey scans. Charge neutralization was accomplished by a low-energy electron flooding. All spectra were referenced to the C1s peak at 284.8 eV. Thermogravimetric analysis (TGA) was performed under argon flow from 50 to 800 oC using a NETZSCH

ST9449

Thermogravimetric

Analyzer.

N2

adsorption–desorption

measurements were carried out on an Omnisorp 100 CX gas adsorption analyzer from Coulter Co to determine the BET surface area. Every sample was degassed at 350 oC for 12 h under a pressure of 10-5 Pa or below. The calorimetric experiment was performed using a C-80 microcalorimeter produced by SETARAM (France) with a sensitivity of 0.10 mW.

2. Results and discussion Structural analysis. The structures of the samples synthesized by varying the contents of EDA were investigated by using XRD as shown in Figure 1, which a cubic spinel structure was synthesized and no impurity peaks were observed. The lattice parameter, cell volume and crystallite size were determined by indexing the XRD patterns and listed in Table 1, where the crystallite size was calculated based on the Debye–Scherrer formula for the strongest (311) diffraction peak. It can be seen from 6


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Table 1 that the increasing EDA concentration induced the lattice parameter increasing for the E5, E8, E15, and E20, and the crystallite size increasing for the E5, E8, E10, and E15. When the molar ratio of EDA to the metal cations was further increased from 15 to 20 as the samples E15 and E20, the crystallite size decreased from 18.7 to 18.2 nm. The molar ratios of Zn to Fe determined by ICP-AES for these samples are listed in Table 2. These results demonstrated that Zn-doped Fe3O4 spinel structure was synthesized with the present conditions, and the Zn content was decreased with the EDA increasing from 5 to 15 (molar ratio of EDA to the metal ions) and became higher with the EDA further increasing from 15 to 20. Fourier transform infrared (FT-IR) analysis was performed to identify the structure and the functional groups of the samples as shown in Figure 2. The bands around 3414 and 1621 cm-1 were attributed to the O-H stretching vibration and the O-H bending vibration, probably due to the surface water molecules.18 The bands around 433 and 575 cm-1 were attributed to the Zn-O vibration, Fe-O bond vibration, respectively.19 No characteristic peaks of EDA were observed in the spectrum, which indicates the absence of EDA on the surface of the as-prepared samples, which was demonstrated in the following analysis. The morphology and size of the samples were analyzed through the typical TEM images as shown in Figure 3. When no EDA was used, cluster-shaped samples were synthesized with the same method.15-17 However, no cluster can be seen in Figure 3, which demonstrates that the EDA modified the morphology of the sample. Irregular nanoparticles and nanosheets can be seen in Figure 3 for the samples E5, E8 and E10, 7



in which the size of the nanoparticles was about 10-20 nm, the length, width and thickness of these nanosheets were about 20-50 nm, 8-10 nm, 3-4 nm, respectively. Sample E15 consisted of a large quantity of nanosheets with about the same size as the samples E5, E8 and E10. Nanosheets can only be seen for E20 in Figure 3, which the width of the nanosheets increased to about 30 nm. These results indicate that EDA induced the nanosheet formation. Typical HRTEM images of these samples are also shown in Figure 3. (111) facet with 0.50 nm for the distance between two adjacent planes can be seen clearly for the nanosheets, which indicated that the nanosheet grew along [111] direction. The selected area diffraction (SAED) pattern of the E15 is shown in Figure 4A, which reveals the crystalline nature of ferrite samples, and the diffraction rings are well in consistency with the hkl planes present in the cubic spinel structure obtained from XRD. To analyze the purity and elemental composition of the E15, energy dispersive X-ray spectroscopy (EDS) was employed as shown in Figure 4B, which clearly depicted that the as-synthesized sample was free from any kind of elemental impurities. Formation mechanism. Many metallic cations can coordinate with EDA to form stable complexes.19 Compared with the free cations as reactants, the reaction mechanism may be changed when these complexes were used as reactants. In the present study, E15 was selected to be studied the formation mechanism by in situ microcalorimetry. A typical microcalorimetric curve is shown in Figure 5. Compared with the microcalorimetric curve without EDA as reported in our previous work,21 significant differences can be found. Stronger peaks corresponding to the 8


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Fe2(C2H4O2)3, ZnC2H4O2), NaNO3, and gel formations were found from room temperature to 150 oC without EDA. 21 Weaker peaks were only found from room temperature to 200 oC in the present system, where the NaNO3 was synthesized at 159 o

C as analyzed below, and the content of the Fe2(C2H4O2)3 and ZnC2H4O2) was only

about 0.5 wt% determined by TG as shown in the supporting information S1. Compared with 13 wt% of the content of the Fe2(C2H4O2)3 and ZnC2H4O2 without EDA,21 the addition of EDA prevented the Fe2(C2H4O2)3 and ZnC2H4O2) formation. No gel was found in the present system. These differences indicate that the EDA changed the formation mechanism of the Zn-doped ferrite. In order to further study the formation mechanism, seven samples were selected corresponding to crests and troughs of these peaks as shown in Figure 5. Different samples were named as T76, T107, T159, T2003.5, T2008.2 and T2009.0, where 76, 107, 159 and 200 represent the experimental temperatures, and the subscripts as 3.5, 8.2 and 9.0 represent the time (h) kept at 200 oC. No precipitate was found for the T76 and T107. XRD patterns of the solid samples obtained at different reaction temperatures are shown in Figure 6, in which all diffraction peaks of the sample T159 were indexed to NaNO3 (ICDD no. 36-1474). The diffraction peaks of the samples T2003.5 and T2008.2 were indexed to α-(Fe, Zn)OOH and α-Fe2O3 (ICDD no. 65-0390), and no NaNO3 was found, which was agreement with the TG results. The diffraction peaks of the samples T2009.0 were indexed to Fe3O4 (ICDD no. 28-0491) and/or ZnFe2O4 (ICDD no. 22-1012). The molar ratios of Fe to Zn were determined by ICP–AES as 32.8, 502.6, 128.8, and 34.7 for T159, T2003.5, T2008.2 and T2009.0, respectively. These 9



results indicate that in addition of the NaNO3 crystals, the solid sample consisted of a small amount of amorphous alkoxides (Fe2(C2H4O2)3 and ZnC2H4O2 (about 0.5 wt% based on TG) for T159. α-FeOOH and α-Fe2O3, and a small amount of α-Zn3(OOH)2 were synthesized for T2003.5. The α-Zn3(OOH)2 content increased with the experimental time increase from 3.5 to 8.2 h, which the molar ratio of Fe to Zn decreased from 502.6 to 128.8. When the experimental time further increased from 8.2 to 9.0 h at 200 oC, a spinel structure was found and Zn content was significantly increased, which demonstrated that Zn-doped Fe3O4 was synthesized. Fourier transform infrared (FT-IR) analysis was performed to identify the structure and the functional groups of the samples as shown in Figure 7. The bands around 3345 and 1661cm-1 were attributed to the O-H stretching vibration and the O-H bending vibration. The bands around 424 and 536 cm-1 were attributed to the Zn-O vibration and Fe-O bond vibration, respectively. For samples T159, T2003.5 and T2008.2, the two bands around 2871 and 2934 cm-1 were attributed to the CH2symmetrical stretching vibration and asymmetrical stretching vibration, respectively. The bands at 1086 and 1130 cm-1 are assigned to the C-N stretching vibrations and the band around 1382 and 1535 cm-1 were attributed to the asymmetric stretching vibration of C-H bond vibration and N-H bond vibration, respectively.22 No band corresponding to EDA was found for T2009.0 in Figure 7, which indicated that no EDA was contained in the Zn-doped ferrite based on the XRD. XPS survey spectra of the T159 and T2003.5 are shown in Figure 8. Peak values at 1072, 1046.7, 1023.4, 726.1, 712.1, 533.4, 408.4, and 285.2 eV can be indexed to 10


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binding energies of Na 1s, Zn 2p1/2, Zn 2p3/2, Fe 2p1/2, Fe 2p3/2, O 1s, N 1s, and C 1s, respectively, which confirmed the existence of Na, Zn, Fe, O, N and C elements in the samples. Na 1s was found for T2003.5, and no NaNO3 was determined by XRD, which indicated small amount NaNO3 mag be absorbed at the T2003.5 surface. Fe2+ was determined for T2003.5. The details for XPS analysis were listed in the supporting information as Figures S2-4. Based on the results listed above, a mechanism for the Zn-doped Fe3O4 formation was proposed. In the beginning, the complex cations were formed as the following. Fe3+ + 3EDA

[Fe(EDA)3]3+

(1)

Zn2+ + 3EDA

[Zn(EDA)3]2+

(2)

Compared with Fe3+ and Zn2+ free ions, the [Fe(EDA)3]3+ and [Zn(EDA)3]2+ formation prevented the Fe2(C2H4O2)3 and ZnC2H4O2 synthesis. When the experimental temperature increased to 159 oC, NaNO3 crystals and a small amount of Fe2(C2H4O2)3 and ZnC2H4O2 were synthesized. -

Na + + NO3 o NaNO3

(3)

When Zn-doped Fe3O4 was synthesized without EDA,21 NaNO3 crystals were synthesized at about 99 oC. And the amount of Fe2(C2H4O2)3 and ZnC2H4O2 was significant higher than that fabricated in the present system. The reason may be that the complex cations formation decreased the free Fe3+ and Zn2+ concentrations. As a chelating agent, EDA influenced the growth of particles under hydrothermal reaction.22 The free Fe3+ and Zn2+ concentrations dissociated from the complex 11



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cations became higher with the experimental temperature increased. A small amount of Fe2(C2H4O2)3 and ZnC2H4O2 was synthesized with the temperature increased to 159 oC. 2Fe3+ + Zn2++ 4C2H6O2

Fe2(C2H4O2)3 + ZnC2H4O2 + 8H+

(4)

At the same time, the following equation occurred. H+ + CH3COO-

CH3COOH

(5)

Thus, NaNO3 crystals were formed through the electrostatic interaction between Na+ and NO3-. With the experimental temperature increase to 200 oC, the hydrolysis of CH3COOand EDA occurred, and OH- was released. α-(Fe, Zn)OOH and α-Fe2O3 were synthesized through the reaction between the Fe3+ and Zn2+ with the OH- as the following, in which the equation (7) induced the Zn content decrease. Compared with the reaction at 200 oC, the α-(Fe, Zn)OOH and α-Fe2O3 were fabricated at 159 oC without EDA.21 [Fe(EDA)3]3+ + [Zn(EDA)3]2+ + 3OH2α-(Fe, Zn)OOH + 6EDA

α-(Fe, Zn)OOH + H2O + 6EDA (6) α-Fe2O3 + 2 [Zn(EDA)3]2+ + H2O

(7)

At the same time, Fe2+ was found at 200 oC for 3.5 h through the following equation (8), which was formed at 159 oC without EDA. Zn-doped Fe3O4 crystals were determined at 200 oC for about 9 h, and the Zn content was increased with the experimental time increase with the equation (9).

HOCH2CH2OH 6α Fe2O3 o 4Fe3O4 O H C C HO2H2O

12


(8)

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Fe3O4 + [Zn(EDA)3]2+

ZnFe2O4 + [Fe(EDA)3]2+

(9)

Typical TEM images of the samples are shown in Figure 9. For the sample T159, nanoparticles were found and amorphous morphology was seen, which NaNO3 crystals and a small amount of amorphous Fe2(C2H4O2)3 and ZnC2H4O2 were fabricated based on the analysis above. Nanosheets and cube-shaped structures were observed for the samples T2003.5 and T2008.2, which α-(Fe, Zn)OOH and α-Fe2O3 were synthesized. When the experimental time increased from 8.2 to 9.0 h kept at 200 o

C, nanosheets and nanoparticles were found, which Zn-doped Fe3O4 crystals were

synthesized. When the experimental time further increased to 24 h, almost pure nanosheets were fabricated as shown in Figure 3. Magnetic property. The magnetic hysteresis loops of the synthesized samples were measured at room temperature by using a VSM under a maximum applied field from -10 to 10 kOe as shown in Figure 10. The saturation magnetization (Ms), remanent magnetizations (Mr) and coercivities (Hc) are listed in Table 2, and the maximum Ms value is 119 emu/g for E15, which is higher than those reported such as 80.93 emu/g (for Zn0.2Fe2.8O4 without EDA)10 and 34.78 emu/g.22 In order to explain the Ms change, molar ratios of Fe2+ to Fe3+ in the samples were calculated based on the molar ratio of Zn to Fe determined by ICP-AES and the chemical composition of the Zn-doped Fe3O4 as ZnxFe2+1-xFe3+2O4, which are listed in Table 2. The result as listed in Table 2 demonstrated that the molar ratio of Zn to Fe was affected by the addition of EDA. The saturation magnetization increased from 64.7 to 119 emu/g for E5 to E15, which is in direct proportion to the molar ratios of 13



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Fe to Zn or Fe2+ to Fe3+. Zn2+ ions as non-magnetic in nature occupied tetrahedral sites (as A site) and Fe3+ ions resided in octahedral sites (as B site),23,

24

which

weakened the A-O-B interaction due to dilution of spin moments and induced the saturation magnetization decrease. However, E20 is obviously not according to this change. In order to study this change, XPS spectra were determined for the samples E10, E15 and E20 as shown in Figure 11. The analysis for XPS is listed in the supporting information as Figure S5-7. From the XPS data, occupation formula for the

samples

E10,

E15

and

E20

(Zn2+0.104Fe3+0.896)A[Fe2+0.896Fe3+1.104]BO4,

are

as

the

following,

(Zn2+0.068Fe3+0.932)A[Fe2+0.932Fe3+1.068]BO4

and (Zn2+0.050Fe3+0.950)A[Zn2+0.032Fe2+0.918Fe3+1.050]BO4, respectively. For the sample E20, Zn2+ ions partly substituted Fe3+ ions at B-sites which reduced the magnetic moment of B-sites and resulted in the net magnetic moment decrease. The molar ratio of Fe2+ to Fe3+ at the surface of the samples were calculated based on XPS and is listed in the Table S1, which is higher than those represented the composition of the sample based on the ICP-AES as listed in Table 2. Octahedral sites are preferentially exposed on the spinel surfaces.25 Temperature dependency of the zero field cooled (ZFC) and field cooled (FC) magnetizations of samples E15 and E20 are shown in Figure 12. The magnetization increases in ZFC curves with the temperature increasing up to a certain value which is called blocking temperature (TB). The plots of ZFC-FC magnetization show thermo-magnetic irreversibility (divergence between FC and ZFC magnetization). This is the property of all magnetic systems exhibiting magnetic hysteresis behavior. 14


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The temperature at which the ZFC and FC curves begin to separate (Tirr) corresponds to the blocking or unblocking temperature of the largest particles. TB and Tirr values are listed in Table 3, where Tirr represents the blocking temperature of particles with the highest energy barrier and the TB is giving the average value of the blocking temperatures of all the particles. The result shows thermomagnetic irreversibility (MFC > MZFC) below a certain temperature Tirr (‫׽‬300 K), which reveals that the systems are in a blocked state for all temperatures below the mentioned one.26 The difference between TB and Tirr corresponds to the width of the blocking temperature distributions, and it also gives information regarding the grain size distributions in the samples.27 The zero-field

57

Fe Mössbauer spectra recorded at room temperature are shown in

Figure 13 for the samples E15 and E20. The computed hyperfine parameters are listed in Table 4. It can be found that the spectra exhibit a superposition of two Zeeman sextets for sample E15 and E20. The spectrum of compounds with the spinel structure is fitted using two sextets denoted as A- and B-sites, in which the fractions of iron ions are directly determined by the relative area ratios of the sub-spectra of corresponding A and B, respectively.28 The outer sextet corresponding to a higher magnetic field (HA) is attributed to Fe3+ at A-site, and the inner sextet corresponding to lower magnetic field (HB) is from Fe2+ and Fe3+ ions at B-site. The molar ratios of Fe3+ at A-site to B-site were calculated to be about 0.67 and 0.78 for E15 and E20, respectively, which were about 0.81 and 0.85 by XPS. The N2 adsorption-desorption isotherms for samples E5-E20 are shown in Figure 15



14. The isotherm is of type IV and displays the H3 hysteresis loop. According to the BET analysis, the BET surface area is shown in Table 5. The BET surface area of the sample E15 was 80.6 m2/g, which has higher surface area than some results as 28 m2/g

29

, 25.94 m2/g

30

and 74 m2/g

31

. A large surface area can be obtained with

nanoparticles dispersed.32

4. Conclusion Zn-doped Fe3O4 magnetic nanosheets with high magnetization and surface area were synthesized by a facile one-step solvothermal method. The Zn-doped Fe3O4 magnetic nanosheets formation mechanism was studied in details using an in-situ calorimetric method. The complexes formation, as [Fe(EDA)3]3+ and [Zn(EDA)3]2+, deceased free Fe3+ and Zn2+ concentrations, which prevented some reactions, and induced some reactions to occur at higher temperature. At the same time, the (111) facets of the Zn-doped Fe3O4 became stable, which induced the nanosheets formation. These results demonstrated that the EDA can change the sample formation mechanism. The Zn-doped Fe3O4 nanosheets with large saturation magnetization and high surface area show potential applications in different fields such as adsorption, biomolecular separations, and drug targeted delivery.

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Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS The authors gratefully acknowledge the financial support from the National Nature Science Foundations of China (21673204 and 21273196) and the Priority Academic Program Development of Jiangsu Higher Education Institutions.

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Reference (1) Sakellari, D.; Brintakis, K.; Kostopoulou, A.; Myrovali, E.; Simeonidis, K.; Lappas, A. Ferrimagnetic Nanocrystal Assemblies as Versatile Magnetic Particle Hyperthermia Mediators. Mater. Sci. Eng., C. 2016, 58, 187-193. (2) Wang, D.; Zhou, W.; Zhang, Y.; Wang, Y.; Wu, G.; Yu, K.; Wen, G. A Novel One-step Strategy Toward ZnMn2O4/N-doped Graphene Nanosheets with Robust Chemical Interaction for Superior Lithium Storage. Nanotechnology. 2016, 27, 045405(10pp). (3) Tan, J.; Wan, J.; Guo, J.; Wang, C. Self-sacrificial Template-induced Modulation of Conjugated Microporous Polymer Microcapsules and Shape-dependent Enhanced Photothermal Efficiency for Ablation of Cancer Cells. Chem. Commun. 2015, 51, 17394-17397. (4) Wang, W.; Zang, C; Jiao, Q. Synthesis, Structure and Electromagnetic Properties of Mn-Zn Ferrite by Sol–gel Combustion Technique. J. Magn. Magn. Mater. 2014, 349, 116-120. (5) Liang, J.; Ma, H.; Luo, W.; Wang, S. Synthesis of Magnetite Submicrospheres with Tunable Size and Superparamagnetism by A Facile Polyol Process. Mater. Chem. Phys. 2013, 139, 383–388. (6) Luo, B.; Xu, S.; Luo, A.; Wang, W. R.; Wang, S. L.; Guo, J. Mesoporous Biocompatible and Acid-degradable Magnetic Colloidal Nanocrystal Clusters with Sustainable Stability and High Hydrophobic Drug Loading Capacity. Acs Nano. 2011, 5, 1428-1435. 18


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(7) Xuan, S.; Wang, F.; Wang, Y. X. J.; Yu, J. C.; Leung, C. F. Facile Synthesis of Size-controllable Monodispersed Ferrite Nanospheres. J. Mater. Chem. 2010, 20, 5086-5094. (8) Yuan, Y.; Chen, L.; Yang, R.; Lu, X.; Peng, H.; Luo, Z. Solid-state Synthesis and Characterization of Core-shell CoFe2O4-carbon Composite Nanoparticles from A Heterometallic Trinuclear Complex. Mater. Lett. 2012, 71, 123-126. (9) Tang, Y.; Liu, Y.; Li, W.; Xie, Y.; Li, Y.; Wu, J. Synthesis of Sub-100 nm Biocompatible Superparamagnetic Fe3O4 Colloidal Nanocrystal Clusters as Contrast Agents for Magnetic Resonance Imaging. Rsc Adv. 2016, 6, 62550-62555. (10) Liu, J.; Bin, Y. Z.; Matsuo, M. Magnetic Behavior of Zn-doped Fe3O4 Nanoparticles Estimated in Terms of Crystal Domain Size. J. Phys. Chem. C. 2012, 116, 134-143. (11) Park, J.; Jin, J.; Kwon, S. G.; Jang, Y.; Hyeon, T. Synthesis of Monodisperse Spherical Nanocrystals. Angew. Chem. Int. Ed. 2007, 46, 4630-4660. (12) Yin, Y.; Alivisatos, A. P. Colloidal Nanocrystal Synthesis and The Organic-inorganic Interface. Nature. 2005, 437, 664-670. (13) Ding, Y.; Liu, F.; Jiang, Q.; Du, B.; Sun, H. 12-hydrothermal Synthesis and Characterization of Fe3O4 Nanorods. J. Inorg. Organomet. P. 2013, 24, 2231-2234. (14) Zhu, L. P.; Xiao, H. M.; Zhang, W. D.; Yang, Y.; Fu, S. Y. Synthesis and Characterization of Novel Three-dimensional Metallic Co Dendritic Superstructures by A Simple Hydrothermal Reduction Route. Cryst. Growth. Des. 2008, 8, 1113-1118. (15) Liu, J.; Zhang, Y.; Nan, Z. Facile Synthesis of Stoichiometric Zinc Ferrite 19



Nanocrystal Clusters with Superparamagnetism and High Magnetization. Mater. Res. Bull. 2014, 60, 270-278. (16) Zhao, B.; Nan, Z. One-pot Synthesis of ZnLaxFe2-xO4 Clusters without any Template and Their Possible Application in Water Treatment. J. Mater. Chem. 2012, 22, 6581-6586. (17) Liu, X.; Liu, J.; Zhang, S.; Nan, Z.; Shi, Q. Structural, Magnetic, and Thermodynamic Evolutions of Zn-doped Fe3O4 Nanoparticles Synthesized Using A One-step Solvothermal Method. J. Phys. Chem. C. 2016, 120, 1328-1341. (18) Prasad, B. D.; Nagabhushana, H.; Thyagarajan, K.; Nagabhushana, B. M.; Jnaneshwara, D. M.; Sharma, S. C. Temperature Dependent Magnetic Ordering and Electrical Transport Behavior of Nano Zinc Ferrite from 20 to 800K. J. Alloy. Compd. 2014, 590, 184-192. (19) Rameshbabu, R.; Ramesh, R.; Kanagesan, S.; Karthigeyan, A.; Ponnusamy, S. Synthesis and Study of Structural, Morphological and Magnetic Properties of ZnFe2O4 Nanoparticles. J. Supercond. Nov. Magn. 2014, 27, 1499-1502. (20) Barick, K. C.; Aslam, M.; Lin, Y. P.; Bahadur, D.; Prasad, P. V.; Dravid, V. P. Novel and Efficient MR Active Aqueous Colloidal Fe3O4 Nanoassemblies. J. Mater. Chem. 2009, 19, 7023-7029. (21) Liu, J.; Nan, Z.; Gao, S. In Situ Microcalorimetry Study of ZnFe2O4 Nanoparticle Formation under Solvothermal Conditions. Dalton T. 2015, 44, 17293. (22) Zhao, H.; Liu, R.; Zhang, Q.; Wang, Q. Effect of Surfactant Amount on The Morphology and Magnetic Properties of Monodisperse ZnFe2O4 Nanoparticles. Mater. 20


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Res. Bull. 2015, 75, 172-177. (23) Najmoddin, N.; Beitollahi, A.; Devlin, E.; Kavas, H.; Mohseni, S. M.; Åkerman, J. Magnetic Properties of Crystalline Mesoporous Zn-substituted Copper Ferrite Synthesized under Nanoconfinement in Silica Matrix. Micropor. Mesopor. Mat. 2014, 190, 346-355. (24) Ibrahim, I.; Ali, I. O.; Salama, T. M.; Bahgat, A. A.; Mohamed, M. M. Synthesis of Magnetically Recyclable Spinel Ferrite (MFe2O4, M= Zn, Co, Mn) Nanocrystals Engineered by Sol Gel-hydrothermal Technology: High Catalytic Performances for Nitroarenes Reduction. Appl. Catal. B-Environ. 2016, 181, 389-402. (25) Jacobs, J. P.; Maltha, A.; Reintjes, J. G. H.; Drimal, J.; Ponec, V.; Brongersma, H. H. The Surface of Catalytically Active Spinels. J. Catal. 1994, 147, 294-300. (26) Ferrari, S.; Aphesteguy, J. C.; Saccone, F. D. Structural and Magnetic Properties of Zn Doped Magnetite Nanoparticles Obtained by Wet Chemical Method. IEEE. T. Magn. 2014, 51, 1-6. (27) Cannas, C.; Casula, M. F.; Concas, G.; Corrias, A.; Gatteschi, D.; Falqui, A. Magnetic Properties of γ-Fe2O3-SiO2 Aerogel and Xerogel Nanocomposite Materials. J. Mater. Chem. 2001, 11, 3180-3187. (28) Wang, J.; Wu, H. Y.; Yang, C. Q.; Lin, Y. L. Room Temperature Mössbauer Characterization of Ferrites with Spinel Structure. Mate. Charact. 2008, 59, 1716-1720. (29) Wang, Q.; Deng, J.; Sun, J.; Shu, C. M.; Luo, Z.; Liu, B. Flame Propagation Characteristics and Combustion Mechanism of FeOOH-coated Zirconium Particles. J. 21



Therm. Anal. Calorim. 2012, 126, 1-9. (30) Xin, X.; Wei, Q.; Yang, J.; Yan, L.; Feng, R.; Chen, G. Highly Efficient Removal of Heavy Metal Ions by Amine-functionalized Mesoporous Fe3O4 Nanoparticles. Chem. Eng. J. 2012, 184, 132-140. (31) Khosravi, M.; Azizian, S. Synthesis of Fe3O4 Flower-like Hierarchical Nanostructures with High Adsorption Performance Toward Dye Molecules. Colloid. Surface. A. 2015, 482, 438-446. (32) Ismail, A. A.; Bahnemann, D. W. Mesoporous Titania Photocatalysts: Preparation, Characterization and Reaction Mechanisms. J. Mater. Chem. 2011, 21, 11686-11707.

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Table 1

Lattice parameter, cell volume, and crystallite size of the samples.

Sample

Lattice parameter (Å)

Cell volume (Å3)

Crystallite size(nm)

E5

8.3955

591.8

12.1

E8

8.4250

598.0

13.7

E10

8.5729

630.1

14.6

E15

8.6164

639.7

18.7

E20

8.7262

664.5

18.2

Table 2. Saturation magnetization (Ms), remanent magnetizations(Mr) and coercivities(Hc) of different samples as well as molar ratio of Zn to Fe and Fe2+ to Fe3+ for the samples determined by ICP-AES

Sample

Molar ratio

Molar ratio

(Zn /Fe)

(Fe2+/Fe3+)

21.3

0.095

0.368

Zn0.26Fe2.74O4

13.9

49.5

0.045

0.435

Zn0.13Fe2.87O4

96.6

6.10

23.7

0.042

0.440

Zn0.12Fe2.88O4

E15

119

12.6

47.7

0.030

0.457

Zn0.09Fe2.91O4

E20

70.4

11.1

72.2

0.034

0.451

Zn0.10Fe2.90O4

Ms

Mr

(emu/g)

(emu/g)

E5

64.7

5.48

E8

93.3

E10

Hc (Oe)

23


ZnxFe3-xO4


Page 24 of 48

Table 3. Summary of magnetic parameters for the samples.

TB(K)

Tirr(K)

E15

200

~300

E20

190

~300

Table 4. Mössbauer parameters for samples E15 and E20.

Sample

IS˄mm/s˅

QS˄mm/s˅

Hf(T)

ARE˄%˅

site

0.30

-0.03

47.1

40

A site

0.38

-0.01

44.3

60

B site

0.30

-0.00

47.4

44

A site

0.50

0.03

43.3

56

B site

E15

E20

Table 5. Surface area of the Samples

E5

E8

E10

E15

E20

60.8

54.0

60.6

80.6

49.3

BET surface area 2

˄m /g˅

24


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Zn-doped Fe3O4 Nanosheets Formation Induced by EDA with High Magnetization and Investigation on the Formation Mechanism Jie Zhu and Zhaodong Nan

“TOC Graphic”

25



（311）

E20 Intensity(a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 48

（111）

（220）

（440）（511）（422）

（400）

E15 E10 E8 E5

10

20

30

40

50

60

70

2Theta(degree)

Figure 1. XRD patterns of the samples

1


80

Page 27 of 48

E5 E8 transparency%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


E10 433

E15 E20 1621

3414

575

4000

3500

3000

2500

2000

1500 -1

wavenumber(cm )

Figure 2. FTIR spectra of the samples

1


1000

500



Page 28 of 48

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Figure 3. TEM and HRTEM images of the samples, where 5, 8, 10, 15 and 20 represent the samples E5, E8, E10, E15 and E20, respectively.



（311）（220）（111）（222）

Figure 4. SAED pattern (A) and EDS pattern (B) for the sample E15.

1


Page 30 of 48

Page 31 of 48

200

T2003.5

40

180

T2008.2

140 120 20 100 80 10 60

T107 T159 T76

40

0 20

A 0

10

20

30

40

Time/h

Figure 5. Microcalorimetric curve for sample E15

1


50

Temperature/oC

160

T2009.0

30

Heatflow/mW

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



T2009.0 T2008.2 

Intensity(a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 32 of 48











T2003.5

 



  10

20

T159 30

NaNO3

40

50

60

70

80

2Theta(degree) (Fe,Zn)OOH -Fe2O3

Figure 6. XRD diffraction patterns of the samples synthesized at different reaction temperature and time.

1


Page 33 of 48

T159

Zn-O

T2003.5 transparency%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


T2008.2

T2009.0

N-H CH2-

C-N

C-H

O-H Fe-O

O-H

4000

3500

3000

2500

2000

1500

1000

500

-1

wavenumber(cm )

Figure 7. FTIR spectra of the samples synthesized at different reaction temperature and time.

1



T159

O1s

Fe2p3/2 Fe2p1/2 C1s

0

200

N1s

400

600

800

1000

Zn2p3/2

T2003.5

Zn2p1/2 Na1s

1200

Zn2p1/2 Na1s

O1s

Relative Intensity(cps)

Zn2p3/2 Relative Intensity(cps)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 48

Fe2p3/2 Fe2p1/2

C1s N1s

0

200

Binding Energy(eV)

400

600

800

Binding Energy(eV)

Figure 8. XPS survey spectra of the samples T159 and T2003.5.

1


1000

1200

Page 35 of 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 9. TEM images of the samples.

1



E15 E10

120 100

Saturation Magnetization(emu/g)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 36 of 48

E20

80 60

E8 E5

40 20 0 -20 -40 -60 -80 -100 -120 -10000

-5000

0

5000

Applied Field(Oe)

Figure 10. Magnetic hysteresis loops for the samples E5-E20

1


10000

Page 37 of 48

Fe2p3/2 O1s


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Fe2p1/2

Zn2p3/2 Zn2p1/2

C1s E10

E15

E20

0

200

400

600

800

1000

1200

Binding Energy(eV)

Figure 11. XPS survey spectra of the samples.

1



60

E15

45

FC ZFC

50

40

40

35

30

30

(emu/gOe)

(emu/gOe)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

20

Page 38 of 48

E20

FC ZFC

25

20

10

15

0 0

50

100

150

200

250

300

0

50

Temperature(K)

100

150

Temperature(K)

Figure 12. Zero-field-cooling and field-cooling curves of samples

1


200

250

300

Page 39 of 48

1.004

1.004

E15

E20

1.002 1.000

Relative absorption

1.000

Relative absorption

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.998 0.996 0.994

0.996

0.992

0.988 0.992 0.984

0.990 -10

-8

-6

-4

-2

0

2

4

6

8

10

-10

-8

-6

-4

-2

0

2

4

veloctity (mm/s)

veloctity (mm/s)

Figure 13. Mössbauer spectra of samples E15 and E20 at room temperature.

1


6

8

10


240 220 200

-1

180 160

3

Quantity adsorbed / cm g (STP)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

140

Page 40 of 48

E5 E8 E10 E15 E20

120 100 80 60 40 20 0 0.0

0.2

0.4

0.6

0.8

Relative pressure (P/P0)

Figure 14. BET analysis for the samples.

1


1.0

Page 41 of 48

Zn-doped Fe3O4 Nanosheets Formation Induced by EDA with High Magnetization and Investigation on the Formation Mechanism Jie Zhu and Zhaodong Nan* College of Chemistry and Chemical Engineering, Yang Zhou University, 225002 Yangzhou, People’s Republic of China

Support information Thermogrametric curves (TG) of the samples T159, T2003.5, T2008.2 and T2009.0 are shown in Figure S1. For T159, the peaks before 250 °C were ascribed to the evaporation of the H2O adsorbed on the surface of the sample, the peak occurred from 270 to 340 °C was ascribed to the decomposition of the alkoxides (Fe2(C2H4O2)3 and ZnC2H4O2),1 the peak occurred from 350 to 380 °C was ascribed to the decomposition of the NaNO3.2 The lost weight of the alkoxides was 0.5 wt%. For T2003.5 and T2008.2, the mass loss from 300 to 400 oC was mainly due to the dehydroxylation of α-FeOOH,3, 4 which was agreement with that obtained by XRD. For T2009.0, the mass loss corresponding to the dehydroxylation of α-FeOOH cannot be seen, which is agreement with that obtained by XRD. 1

T159

T2003.5

100

100

0

96

Weight (%)

-0.2

Derivative Weight (%/min)

98

90

-3

80

-4 -5

70

-6 60

NaNO3

alkoxide

-2

-7 -8

94

100

200

300

400

500

-0.4 600

50

100

200

o

Temperature ( C)

300

400

500 o

Temperature ( C)

1


600

700

800


-1 0.0

Weight (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



1

Weight (%)

-3 70

-4 -5

60

-6 50

90

100

200

300

400

500

600

700

-1.0

70

60

-7

40

-0.5 80

-8 800

-1.5

100

200

300

400

500

600

700

800

o

o

Temperature ( C)

Temperature ( C)

Figure S1. TG/DTG curves of the samples under N2.

The Fe2p XPS spectra of the samples T159 and T2003.5 are shown in Figure S2. The spectra were fitted with Gaussian function, and the Fe 2p3/2 broad could be divided into 3 sub-peaks. For the sample T159, the energy peaks at 710.8, 712.0 and 713.9 eV were corresponding to the Fe3+ with different chemical environment.5-7 For the sample T2003.5, the energy peaks at 709.8 eV was corresponding to the Fe2+, and both of the two energy peaks at 711.2 and 713.0 eV were corresponding to the Fe3+ in FeOOH.8, 9

T2003.5

T159

2p3/2

2p3/2

2p1/2 Fe

2p1/2 Fe

3+

Counts/s

2+

705

710

715

720

725

730

705

Binding Energy(eV)

710

715

720

725

Binding Energy(eV)

Figure S2. Fe 2p3/2 and Fe 2p1/2 XPS spectra for the samples T159 and T2003.5.

2


730


-2 80

0.0

Weight (%)

-1

90

T2009.0

100

0


T2008.2

100

Counts/s

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 42 of 48

Page 43 of 48

The O1s XPS spectra of samples T159 and T2003.5 are shown in Figure S3. For the sample T159, the sub-peaks at 531.6 and 533.1 eV were corresponding to the O in OH- and H2O, respectively.10, 11 For the sample T2003.5, three sub-peaks at 529.0, 530.5 and 531.9 eV were corresponding to the O in oxyhydroxide, FeOOH and OH-, respectively.7, 9 The Zn2p XPS spectra of these samples T159 and T2003.5 are shown in Figure S4. All samples have only two energy peaks which were corresponding to Zn2p3/2 and Zn2p1/2. The spin orbit splitting of 23 eV indicates the Zn2+ cation.12 T2003.5

T159 H2O

FeOOH

OH

Counts/s

Counts/s

OH

528

-

-

530

532

534

536

538

524

526

528

Binding Energy(eV)

530

532

534

536

538

Binding Energy(eV)

Figure S3. O1s XPS spectra of the samples T159 and T2003.5 T2003.5

Counts/s

T159

Counts/s

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1015

1020

1025

1030

1035

1040

1045

1050

1015

1020

1025

Binding Energy(eV)

1030

1035

1040

1045

1050

Binding Energy(eV)

Figure S4. Zn 2p XPS spectra for the samples T159 and T2003.5.

The O1s XPS spectra for the samples E10, E15 and E20 are shown in Figure S5. The binding energy peaks located at 529.3(4) eV and 531.0±0.2 eV were in good 3



consistent with the oxygen in Fe3O4 or ZnFe2O4, the energy peaks at 532.4 eV and 533.0(1) eV were corresponding to the O2- in H2O and CO2, respectively.

E10

E15

531.2eV

530.8eV



529.3eV 533.1eV

526

528

530

532

534

526

536

E20

532.4eV

529.4eV

528

530

532

534

536

Binding Energy(eV)

Binding Energy(eV)

529.4eV

531.1eV


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 44 of 48

533.0eV

526

528

530

532

534

536

538

540

Binding Energy(eV)

Figure S5. O1s XPS spectra of the samples

The Zn2p XPS spectra for the samples E10, E15 and E20 are shown in Figure S6. A binding energy peak at 1020.0 eV appeared since Zn2p has tetrahedral (Td) bonding with oxygen, a peak at 1022.8 eV was due to the octahedral (Oh) bonding of Zn2p with oxygen.12 For samples E10 and E15, the XPS results indicated that 100 % of Zn2p ions were at the tetrahedral sites. For sample E20, the relative contributions to the overall intensity of Zn2p ions at the tetrahedral and octahedral sites were 61% and 39%, respectively. The consequence suggests that the addition of EDA in the reaction system changed the Zn site in the samples. 4


Page 45 of 48

E15



E10

1020

1025

1030

1035

1040

1045

1020

1050

1025

1030

1035

1040

1045

1050

Binding Energy(eV)

Binding Energy(eV)

E20


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1020

1025

1030

1035

1040

1045

1050

Binding Energy(eV)

Figure S6. Zn 2p XPS spectra for the samples The Fe 2p3/2 broad could be divided into 4 sub-peaks, such as Fe2+(B-site), Fe3+(A-site), Fe3+(B-site) and shake-up, as shown in Figure S7 for the samples E10, E15 and E20. The energy peaks at 708.7±0.3 eV, 710.1±0.5 eV and 711.8±0.3 eV were corresponding to the Fe2+(B-site), Fe3+(A-site), and Fe3+(B-site), respectively. The peak at 713.6±0.2 eV attributes high spin Fe2+ 2p3/2 diagonal peak, which was caused by hybridization between Fe 3d orbital electrons and O 2p orbital electrons.

5



E15

2p1/2

E10

2p3/2

2p3/2

2p1/2 712.0eV

713.8eV

713.8eV Relative Intensity(cps)


711.9eV 710.0eV 708.6eV

705

710

715

720

725

730

710.5eV

709.0eV

705

710

E20

2p1/2

2p3/2 711.5eV 713.4eV

709.8eV 708.4eV

705

710

715

720

715

720

Binding Energy(eV)

Binding Energy(eV)


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 46 of 48

725

730

Binding Energy(eV)

Figure S7. Fe 2p3/2 and Fe 2p1/2 XPS spectra for the samples

6


725

730

Page 47 of 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table S1. Results obtained from XPS spectra and composition at the A and B sites according to the area Position Sample

E10

E15

E20

FWHM

Molar ratio

Peak

Area (Fe2+/Fe3+)

(eV)

(eV)

Fe2+(B-site)

708.678

2.359

2593.695

Fe3+(A-site)

710.205

2.214

2727.002

Fe3+(B-site)

712.190

2.510

3068.964

Fe2+(B-site)

709.270

2.880

2904.685

Fe3+(A-site)

710.805

2.456

2910.051

Fe3+(B-site)

712.249

3.028

3328.545

Fe2+(B-site)

708.570

2.790

2698.742

Fe3+(A-site)

709.899

2.608

2792.816

Fe3+(B-site)

711.777

2.956

3086.796

0.448

0.466

0.459

References (1) Luo, X.; Li, Z.; Xiao, W.; Wang, Q.; Zhong, J. Self-assembled Organogels Formed by Monochain Derivatives of Ethylenediamine. J. Colloid. Interf. Sci. 2009, 336, 803-807. (2) Yu, D.; Sun, X.; Zou, J.; Wang, Z.; Wang, F.; Tang, K. Oriented Assembly of Fe3O4 Nanoparticles into Monodisperse Hollow Single-crystal Microspheres. J. Phys. Chem. B. 2006, 110, 21667. (3) Wang, Q.; Deng, J.; Sun, J.; Shu, C. M.; Luo, Z.; Liu, B. Flame Propagation Characteristics and Combustion Mechanism of FeOOH-coated Zirconium Particles. J. Therm. Anal. Calorim. 2012, 126, 1-9. 7



(4) Khalil, N. M.; Wahsh, M. M. S.; Saad, E. E. Hydrothermal Extraction of α-Fe2O3, Nanocrystallite from Hematite Ore. J. Ind. Eng. Chem. 2015, 21, 1214-1218. (5) Marcus, P.; Olefjord, I. Round Robin on Combined Electrochemical and AES/ESCA Characterization of The Passive Films on FeCr and FeCrMo Alloys. Corros. Sci. 1998, 11, 569-576. (6) Suzuki, S.; Kosaka, T.; Saito, M.; Inoue, H.; Waseda, Y.; Matsubara, E. XPS/GIXS Study of Thin Oxide Films Formed on The Fe-40% Cr Alloy with Trace of Manganese. Scripta. Mater. 1997, 36, 841-845. (7) Brion, D. Etude Par Spectroscopie De Photoelectrons De La Degradation Superficielle De FeS2, CuFeS2, ZnS Et PbS. Appl. Surf. Sci. 1980, 5, 133-152. (8) Yang, W. P.; Costa, D.; Marcus, P.; Yang, W. P.; Marcus, P. Resistance to Pitting and Chemical Composition of Passive Films of A Fe17%Cr Alloy in Chloride-containing Acid Solution. J. Electrochem. Soc. 1994, 141, 2669-2676. (9) Barr, T. L. An Esca Study of The Termination of The Passivation of Elemental Metals. J. Phys. Chem. 2002, 82, 1801-1810. (10) Yang, L.; Zhe, W.; Zhai, B.; Shao, Y.; Zhang, Z.; Sun, Y. Magnetic Properties of Eu3+, Lightly Doped ZnFe2O4, Nanoparticles. Ceram. Int. 2013, 39, 8261-8266. (11) Jin, W. X.; Ma, S. Y.; Tie, Z. Z.; Jiang, X. H.; Li, W. Q.; Luo, J. Hydrothermal Synthesis of Monodisperse Porous Cube, Cake and Spheroid-like α-Fe2O3 Particles and Their High Gas-sensing Properties. Sensors Actuat B-Chem. 2015, 220, 243-254. (12) Liu, Y.; Wei, S.; Tian, H.; Tong, H.; Xu, B. Characterization of Soft Magnetic Spinel Ferrite Coating Prepared by Plasma Spray. Surf. Coat. Tech. 2014, 258, 189-199. 8


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Zn-Doped Fe - ACS Publications - American Chemical Society

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