The document summarizes an internship project studying the effects of adding gold to iron nanoparticles synthesized using an arc-in-water method. Key findings include:
1) TEM analysis found that adding gold tended to reduce the average particle size of iron nanoparticles, with the smallest particles seen at around 35-45% gold content by weight.
2) XRD and EDX analysis confirmed the formation of iron-gold alloys. The ratio of alloy to gold peaks was highest at intermediate gold contents.
3) Magnetic susceptibility measurements showed that the maximum real susceptibility value occurred at similar intermediate gold compositions to those giving smallest particles and highest alloy formation.
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1. Internship at : Department of Chemical Engineering, Katsura Campus, Kyoto University
(4th koza)
Duration : Two months (2nd June to 28th July 2014)
Presented by : Mr. Jirapat Pakchamsai (Jojo)
From : Chulalongkorn University, Thailand.
Influence of Au-addition on
some physical properties of Fe-nanoparticles
synthesized by gas-injected arc–in-water method
2. Introduction
• Background
• Carbon nanomaterials : Carbon nanotubes(CNTs) and Carbonbon nanohorns(CNHs)
• CNH
• Properties :
• Has a unique structure which is different from CNT
• Has high surface area
• Has good chemical stability
• Applications : (when combined with metal nanoparticles)
• Catalysts support : Catalysts for decomposition of methane
by stream to generate hydrogen
• Gas sensor
• Fuel cell
• Energy storage
• Drug delivery : Incorporate various molecules inside Single-Wall Nanohorns (SWNH) from
various solutions
• Magnetic Application :
• Magnetic trap
• Magnetic mobility
• Limitation :
• Large-scale preparation with high purification is not available
3. Introduction(2)
• Synthesis Procedure :
• Chemical method :
• Reduction of ions in aqueous solutions : This method requires
chemicals
• Physical method :
• Laser ablation : This method requires big instruments
• Arc-Discharge : This method is applicable in small-scale experiment and
low cost
• Etc.
4. Introduction(3)
• Motivations
• In the past :
• Arc-Discharge method can produce CNTs, CNHs, and Metal-CNHs (M-CNHs)
• Nitrogen gas injection can increase the yield of CNHs
Plum(2012)
: Controlled Syntheses of Various
Palladium Alloy Nanoparticles Dispersed in
Single-Walled Carbon Nanohorns by One-
Step formation Using an Arc Discharge
Method
: Study various alloy of Pd + Ag, Cu, Ni,
Fe, W, Pt, Au, Mo, Nb, and Ti
: Observe that if the boiling temperature is
higher than arc temperature, there will be
NO alloy
: Particle size can be estimated by boiling
temperature, melting temperature, surface
tension, and atomic weight
Au may reduce the particle size
Hirama
Yamada
Ice
: Effect of Fe/Fe2O3 loading on
catalytic activity of sulfonated
single-walled carbon nanohorn
for esterification of palmitic acid
: Study the effect of Fe
Effect of Fe
MY RESEARCH
5. Introduction(4)
• Objectives
• To study the effects of Au addition on some physical properties
• Particle Size Distribution TEM
• Composition of Product TEM, XRD, and EDX
• Magnetic Properties AC magnetic susceptibility
6. Experimental Details
• Apparatus and Main Materials
• Arc Machine
• Nitrogen gas Supplier
• Power Supply
• Graphite Rods
• Distilled Water
• Metal Wires (Fe-wire and Au-wire)
• Driller
7. Experimental Details(2)
• Setup Conditions
• Distilled Water : 3000mL
• Graphite Rod (Anode) : Diameter(Ø) 6.15mm, Length(L) 76mm
(with 2mm Ø hole)
• Graphite Rod (Cathode) : Diameter(Ø) 20mm, Length(L) 55mm
(with upper four 2mm Ø holes and lower 10mm Ø hole)
• Power Supply : Discharge Current 100A
• Velocity of Lower Electrode : 1.5mm/s
• Distance of Lower Electrode Travel(Vertically) : 67mm
• Time of Reaction : 30s
• Nitrogen Gas Flow Rate : 10L/min
• Voltage : 30volt
55mm
45mm
8. Experimental Details(3)
• Cross-sectional view
Upper Electrode (Cathode)
Lower Electrode (Anode)
Ø 15 mm
Ø2mm
Ø 20 mm
Ø 10 mm
For Pure CNH
Ø 6.15 mm
For Metal-CNH
Ø 2 mm
Ø 6.15 mm
9. Experimental Details(4)
• Graphite Rods(Anode) Information
• SET A (keep Fe/Au ratio constant + change total metal amount)
• SET B (keep Fe supply amount constant + change Fe/Au ratio)
Diameter(mm) Pitch
Distance(mm)
Weight Ratio
of Fe/Au
Number of
Au-wire
Remark
Fe Au
0.3 0.3 1.5 1 1 Twisted
together
0.5 0.3 2 1 1 Au in spiral
0.6 0.3 2.5 1 1 Au in spiral
0.8 0.3 3 1 1 Au in spiral
Diameter(mm) Pitch
Distance(mm)
Weight Ratio
of Fe/Au
Number of
Au-wire
Remark
Fe Au
0.8 0.3 4 2.906 1 Au in spiral
0.8 0.3 4 1.457 2 Au in spiral
0.8 0.3 4 0.58 5 Au in spiral
A1
A2
B3
B4
A3
A4
B1
13. Results and Discussions
• Particle Size Analysis
• Analyzed by TEM (Transition Electron Microscope)
Raw CNH
100nm
Fe-CNH
Examples of TEM images
50nm 20nm
15. Results and Discussions(3)
• Examples of TEM images and Histograms
A1 : Au0.3Fe0.3
120k
50nm
A4 : Au0.3Fe0.8
120k
50nm
0
10
20
30
40
50
60
70
0-2 4-6 8-10 12-14 16-18 20-22
0
10
20
30
40
50
60
70
NumberofParticles
NumberofParticles
Size of Particle(nm)
Size of Particle(nm)
16. Results and
Discussions(4)
SETA (Fe:Au=1:1)0
10
20
30
40
50
60
70
80
90
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
0
10
20
30
40
50
60
70
80
90
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
0
10
20
30
40
50
60
70
80
90
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
0
10
20
30
40
50
60
70
80
90
Fe0.3
Fe0.8
Fe0.6
Fe0.5
5
6
7
8
9
10
11
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Diameter of Fe-wire(mm)
Averagesize(nm)
The average particle size is larger
when diameter of Fe-wire increases.
Addition of Au makes the particle size
smaller in most cases.
With Au
Without Au
7.4
8.7 8.6
9.3
5
6
7
8
9
10
11
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Diameter of Fe-wire(mm)
Averagesize(nm)
With Au
Without Au
17. SETB(Fe=0.8,Fe:Auvary)
5
6
7
8
9
10
11
12
13
14
20 30 40 50 60 70
Without Au
With Au
Averagesize(nm) Percent of Au in sample (wt%)
Results and Discussions(5)
0
10
20
30
40
50
60
70
80
90
100
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
0
10
20
30
40
50
60
70
80
90
100
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
0
10
20
30
40
50
60
70
80
90
100
0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22
Fe : Au 2.91(wt%)
Fe : Au 0.58(wt%)
Fe : Au 1.46(wt%)
Size of Particle(nm)
Size of Particle(nm)
Size of Particle(nm)
NumberofParticlesNumberofParticlesNumberofParticles
Without Au
5
6
7
8
9
10
11
12
13
14
20 30 40 50 60 70
With Au
Percent of Au in sample (wt%)Averagesize(nm)
There is a maximum point for particle size.
This point is in the range of 35-45 percent of Au.
18. CNH
Fe-Powder
Au-Powder
T1
T2
T3
20 25 30 35 40 45 50 55 60 65 70
Fe0.5Au0.3
(same weight)
A2
27
45 65
38
44 64
C
Fe
Au
T = Template
A = Same weight of Au and Fe
B = Different weight of Au and Fe
R = Reference
Intensity(relative)
2theta(degree)
Results and Discussions(6)
• Alloying Component Determination
• Analyzed by XRD (X-Ray Diffraction)
Examples of XRD Patterns
from SET A
20. SET A Example:A2Fe0.5Au0.3sameweight
-500
0
500
1000
1500
2000
2500
3000
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
experiment Au alloy total
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
RatioofAlloyandAu
Diameter of Fe-wire (mm.)
Results and Discussions(8)
2theta(degree)
Intensity(relative)
The Ratio of Alloy/Au
is calculated by fitting
the Lawrence
Distribution curve
with Experimental
curve
21. • There are some consistent information between average particle size graph
and Ratio of Alloy/Au graph
Results and Discussions(9)
5
6
7
8
9
10
11
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Diameter of Fe-wire(mm)
Averagesize(nm)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
RatioofAlloyandAu
Diameter of Fe-wire (mm.)
SET A
22. CNH
Fe-Powder
Au-Powder
20 25 30 35 40 45 50 55 60 65 70
Fe0.8-Au0.3-1wire
(diff weight, same length)
T1
T2
T3
B1
27
45 65
38
44 64
C
Fe
Au
T = Template
A = Same weight of Au and Fe
B = Different weight of Au and Fe
R = Reference
Results and Discussions(10)Intensity(relative)
2theta(degree)
Examples of XRD Patterns
from SET B
23. 20 25 30 35 40 45 50 55 60 65 70
Fe0.8-Au0.3-1wire
(diff weight, same length)
B1
Results and Discussions(11)
2theta(degree)
Examples of XRD Patterns
24. SET B Example:B1Fe0.8Au0.3-1wire(diffweight,samelength)
-1000
-500
0
500
1000
1500
2000
2500
3000
3500
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
experiment Au alloy total
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 10 20 30 40 50 60 70
RatioofAlloyandAu
Weight percent of Au
Results and Discussions(12)
2theta(degree)
Intensity(relative)
The Ratio of Alloy/Au
is calculated by fitting
the Lawrence
Distribution curve
with Experimental
curve
26. 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 10 20 30 40 50 60 70
RatioofAlloyandAu
Percent of Au
Results and Discussions(14)
0
5
10
15
20
25
30
0 10 20 30 40 50 60 70
SET A SET B
Max(Re(χ)/g)
0
10
20
30
40
50
60
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
With Au
Without Au
Max(Re(χ)/g)
Diameter of Fe-wire (mm)
Percent of Au
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
RatioofAlloyandAu
Diameter of Fe-wire (mm.)
For SET A (keep Fe/Au in feed, change total metal),
alloying with Au leads to the increase of magnetic
susceptibility. In comparison with “without Au” case, magnetic
susceptibility is increased by adding Au. Such a trend is
against initial expectation.
But for SET B (keep Fe in feed at high value, change
Fe/Au ratio), alloying with Au leads to the decrease of
magnetic susceptibility. This is initially expected.
SET A and SET B are contradicted. It is noteworthy that
the influence of Au on magnetic property can be reversed if
Au is remarkably contained.
27. -5000
0
5000
10000
15000
20000
25000
30000
0 1 2 3 4 5 6 7 8
Energy(kV)
Intensity(relative)
x20
Au
Fe
C
C
Results and Discussions(15)
• Composition Determination
• Analyzed by EDX (Energy Dispersive X-ray spectroscopy)
Example : A1 Fe0.3 Au0.3 same weight
28. Results and Discussions(16)
0
1
2
3
4
5
0 0.2 0.4 0.6 0.8 1
Enrichment
factorofAu
Diameter of Fe-wire (mm.)
0
5
10
15
20
25
30
35
0 0.2 0.4 0.6 0.8 1
Diameter of Fe-wire (mm.)
Percentofmetalinclusion
Enrichment factor
=
(Au wt%/Fe wt%)
in product ÷
(Au wt%/Fe wt%)
in sample
SET A
29. Results and Discussions(17)
0
1
2
3
4
5
0 20 40 60 80
EnrichmentofAu
Percent of Au
0
10
20
30
40
50
0 20 40 60 80
Percentofmetalinclusion
Percent of Au
SET B
By taking possible error
into account,
I believe that there is
a tendency that
increasing metallic
amount simply lead
to increase of metal
inclusion.
Enrichment factor
=
(Au wt%/Fe wt%)
in product ÷
(Au wt%/Fe wt%)
in sample
30. Conclusions
SET A(keep Fe/Au ratio in fee, change total metal spply)
SET B(keep Fe supply, change Fe/Au weight ratio)
CNHs dispersed with Fe/Au alloy nanoparticles are produced
by Gas-injected arc-in-water method with two variation sets.
Focus: investigation on controllability of
alloy particle size, Alloy/metal ratio, Fe/Au ratio,
and magnetic susceptibility
1. Increase of metal supply leads to larger particle diameter.
2. Adding Au leads to reduce the Average Particle Size.
3. Increase metals in feed leads to increase alloy content.
4. Increase of metal content leads to reduced Au-enrichment.
5. Magnetic susceptibility is expected to be lower by alloying
with Au. But large Au content may overshadow this trend.
Main findings