Formation Pathways of Magnetite Nanoparticles by Coprecipitation ...
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Formation Pathways of Magnetite Nanoparticles by Coprecipitation Method Taebin Ahn†, Jong Hun Kim†, Hee-Man Yang†, Jeong Woo Lee†, Jong-Duk Kim*,†,‡
†
Department of Chemical and Biomolecular Engineering (BK21 Graduate Program), Korea Advanced Institute of
Science and Technology, Daejeon 305-701, Republic of Korea ‡
Center for Energy and Environment Engineering, Korea Advanced Institute of Science and Technology, Daejeon
305-701, Republic of Korea
* Corresponding author. Tel.: +82 42 3503921 Fax: +82 42 3503910 E-mail address: [email protected]
S1
Table S1. The crystal structures referred to in this study. JCPDS
Iron Oxides
Crystal System
a (Å )
b (Å )
c (Å )
Goethite (FeOOH)
Orthorhombic
4.608
9.956
3.0215
29-0713
Akaganeite (FeOOH)
Tetragonal
10.535
10.535
3.03
34-1266
Lepidocrocite (FeOOH)
Orthorhombic
3.88
12.54
3.07
08-0098
Hematite (Fe2O3)
Hexagonal
5.036
5.036
13.749
33-0664
Maghemite (Fe2O3)
Cubic
8.3515
8.3515
8.3515
39-1346
Magnetite (Fe3O4)
Cubic
8.396
8.396
8.396
19-0629
Card No.
Figure S1. The color of the reaction solution at R ([NH3]/[Fe2+ + Fe3+]) values of (a) 0, (b) 1.5, (c) 2.1, and (d) 3.0 (continuous addition of base).
S2
Figure S2. pH curve as R increases (continuous addition of base).
Figure S3. ATR-FTIR Spectra of samples at R values of (a) 1.5 (continuous addition of base), (b) 2.1 (continuous addition of base), and (c) 2.0 (abrupt addition of base). Subscript A - akaganeite, G - goethite, and L - lepidocrocite. - Stretch, - in plane bend, and - out of plane bend.1 S3
Table S2. Analysis of Figure 5b. Measured values
d-spacing (Å ) Angle between two planes (º)
2.56
2.49
Akaganeite [-1 1 1]
Goethite [100]
(211)
(-3-30)
(0-21)
(040)
2.55
2.48
2.58
2.49
120.0
120.9
121.3
Figure S4. TEM images of various arrow-shaped nanoparticles (2.1 ≤ R ≤ 2.5). Scale bars represent 10nm.
Figure S5. SEM images of various arrow-shaped nanoparticles (2.1 ≤ R ≤ 2.5). Scale bars represent 10nm.
S4
Figure S6. Crystal models of (a,d) goethite, (b,e) hematite, and (c,f) magnetite. (a~c) show the (pseudo)hexagonal array of oxygen atoms. The separation distances between oxygen layers are 2.3Å for goethite, 2.29 Å for hematite, and 2.42 Å for magnetite. Red lines represent unit cells.
Figure S7. Magnetic attraction of samples at R values of (a) 1.95, (b) 2.0, (c) 2.05, (d) 2.1, and (e) 3.0 (continuous addition of base).
REFERENCE (1) Cornell, R. M.; Schwertmann, U. The Iron Oxides: Structure, Properties, Reactions, Occurrences and Uses; 1st ed.; VCH, Weinheim, Germany, 1996.
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Formation Pathways of Magnetite Nanoparticles by Coprecipitation Method Taebin Ahn†, Jong Hun Kim†, Hee-Man Yang†, Jeong Woo Lee†, Jong-Duk Kim*,†,‡
†
Department of Chemical and Biomolecular Engineering (BK21 Graduate Program), Korea Advanced Institute of
Science and Technology, Daejeon 305-701, Republic of Korea ‡
Center for Energy and Environment Engineering, Korea Advanced Institute of Science and Technology, Daejeon
305-701, Republic of Korea
* Corresponding author. Tel.: +82 42 3503921 Fax: +82 42 3503910 E-mail address: [email protected]
S1
Table S1. The crystal structures referred to in this study. JCPDS
Iron Oxides
Crystal System
a (Å )
b (Å )
c (Å )
Goethite (FeOOH)
Orthorhombic
4.608
9.956
3.0215
29-0713
Akaganeite (FeOOH)
Tetragonal
10.535
10.535
3.03
34-1266
Lepidocrocite (FeOOH)
Orthorhombic
3.88
12.54
3.07
08-0098
Hematite (Fe2O3)
Hexagonal
5.036
5.036
13.749
33-0664
Maghemite (Fe2O3)
Cubic
8.3515
8.3515
8.3515
39-1346
Magnetite (Fe3O4)
Cubic
8.396
8.396
8.396
19-0629
Card No.
Figure S1. The color of the reaction solution at R ([NH3]/[Fe2+ + Fe3+]) values of (a) 0, (b) 1.5, (c) 2.1, and (d) 3.0 (continuous addition of base).
S2
Figure S2. pH curve as R increases (continuous addition of base).
Figure S3. ATR-FTIR Spectra of samples at R values of (a) 1.5 (continuous addition of base), (b) 2.1 (continuous addition of base), and (c) 2.0 (abrupt addition of base). Subscript A - akaganeite, G - goethite, and L - lepidocrocite. - Stretch, - in plane bend, and - out of plane bend.1 S3
Table S2. Analysis of Figure 5b. Measured values
d-spacing (Å ) Angle between two planes (º)
2.56
2.49
Akaganeite [-1 1 1]
Goethite [100]
(211)
(-3-30)
(0-21)
(040)
2.55
2.48
2.58
2.49
120.0
120.9
121.3
Figure S4. TEM images of various arrow-shaped nanoparticles (2.1 ≤ R ≤ 2.5). Scale bars represent 10nm.
Figure S5. SEM images of various arrow-shaped nanoparticles (2.1 ≤ R ≤ 2.5). Scale bars represent 10nm.
S4
Figure S6. Crystal models of (a,d) goethite, (b,e) hematite, and (c,f) magnetite. (a~c) show the (pseudo)hexagonal array of oxygen atoms. The separation distances between oxygen layers are 2.3Å for goethite, 2.29 Å for hematite, and 2.42 Å for magnetite. Red lines represent unit cells.
Figure S7. Magnetic attraction of samples at R values of (a) 1.95, (b) 2.0, (c) 2.05, (d) 2.1, and (e) 3.0 (continuous addition of base).
REFERENCE (1) Cornell, R. M.; Schwertmann, U. The Iron Oxides: Structure, Properties, Reactions, Occurrences and Uses; 1st ed.; VCH, Weinheim, Germany, 1996.
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