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Synthesis of Barium Titanate Nanoclusters
Presented by Marc Landeweer
Advisor: Prof. Slamovich
Objectives
• Examine mechanism of barium titanate synthesis
• Create barium titanate nanoclusters– Hydrothermal– Distributed Arc Cluster Source (DACS)
Hydrothermal Synthesis
• BaCl2 or Ba(OH)2 and TiO2 precursors
• Alkaline solution (NaOH)
• Ar Purge Reduce xCO3
• Oven heating for 40+ hrs
• Water wash & centrifuge
• Dry powder
• Analyze
DACS Titania BaTiO3 Synthesis
• Forms TiO2 nanoclusters
• TiO2 nanoclusters added to barium solution, then heated
• Titania added directly to alkaline barium solution
Analysis Methods
• X-Ray Diffraction• Re-sample particle size analyzer (Coulter 250)• Carbonate Examination
– Acid Test (HCl 10%wt)
– Optical Microscopy 200X-500X
• Transmission Electron Microscopy (TEM) 10,000X-350000X
• Electron Diffraction Pattern (using TEM)
• Identifies – Crystal structure– Compound (if crystalline)
• Detects impurities (~5% limit)
• Can be used to estimate particle size
• Requires minimally 0.5 grams of sample
X-Ray Diffraction
TEM/Electron DiffractionTEM/Electron Diffraction
• High Magnification ImagingHigh Magnification Imaging– Determine size & morphologyDetermine size & morphology
• Drawbacks:Drawbacks:– Requires delicate sample preparationRequires delicate sample preparation– Very sensitive to contaminationVery sensitive to contamination
• Electron diffraction pattern Electron diffraction pattern – Identifies crystalline or amorphous Identifies crystalline or amorphous – Used to identify sample and crystal informationUsed to identify sample and crystal information
Particle Size Analyzer
• Uses laser diffraction of suspension
• Limited to about 40nm
• Does not give much information alone– No indication of sample composition– Little morphological data– Requires properly dispersed sample
Control Group
• 060502-01,-02,-03 & 2H– 0.4M Ba; 1.0M NaOH; 1.1:1 Ba:Ti; 40+ hours – Relatively high purity– XRD appears normal for all samples
• 2H shows shift in lattice parameter
• Concentrate analysis of 060502-02– XRD– TEM– Particle Size Analyzer– Acid Test (control)
060502-02 XRD
Particle Size Analysis
0
1
2
3
4
5
6
7
8
9
10
11
60502-02
TEM• Wide Particle Size Distribution• Follows laser diffraction
distribution
• Crystalline• Smallest range ~70nm
12,000X
150,000X
100,000X
Note the large differencein particle size
Group 062502: Ba Concentration
• Adjusted barium concentration– 062502-01 = 0.16M– 062502-02 = 0.08M– 062502-03 = 0.04M
• High Purity Samples
• Examined under XRD, Laser Dispersion, TEM
XRD
• Low Carbonate
• Sharp Peaks
Particle Size Analysis062502
0
1
2
3
4
5
6
7
8
9
10
11
12
0.0400.0530.0700.0930.1230.1620.2140.2840.3750.4960.6570.8691.1491.5202.0102.6603.5194.6566.1588.147
Microns
% b
y v
olu
me
062502-01
062502-02
062502-03
TEM 062502-01
• Still have wide particle size distribution
12,000X
TEM 062502-01
40,000X
TEM 062502-02
100,000X
30,000X
• Very Wide Size Distribution
Smallest Particles Larger Comparable to 062502-01
TEM 062502-03
General Patterns from 062502
• Decreased [Ba] yields larger particles– Higher concentration provides more nuclei for
barium titanate formation
• Results are consistant with proposed dissolution-precipitation mechanism
• Future Approaches:– Adjust Ba Molarity without changing mass
DACS Titania Under TEM
• Amorphous Component
• 300,000X
DACS Synthesis
• I: DACS Titania added to BaCl2 & NaOH [Ba]~0.1M– Phosphine Surfactant
• II DACS Titania with BaOH2 [Ba]~0.1M– Phosphine Surfactant
• III DACS Titania with BaOH2 [Ba]~0.1M– Sodium Citrate Surfactant
• IV DACS Titania mixed with BaCl2 & NaOH [Ba]~0.4M– No Surfactant
• All Samples yielded too little product for proper XRD or particle size evaluation
DACS Syn I
• Grey precipitate formed soon after addition to BaCl2 & NaOH solution
• Grey powder suspected to be barium carbonate
• Washed with DI water and dried to form powder
• Prepared sample for Coulter Machine– Sample data insufficient to produce result
• Performed acid test on DACS Syn I & 060502-02 to compare reaction with dilute hydrochloric acid– Inspected results under optical microscope
• Examined DACS Syn I under TEM
DACS Syn II & III
• Processed with Barium Hydroxide– Formed barium carbonate precipitate too quickly
– Used filter to remove precipitate
• DACS Syn II – Used 06/21 Titania– Bis(p-sulfonatophenyl) phenyl phosphine dihydrate dipotassim
salt
• DACS Syn III – Used 0718 Titania– Using Sodium Citrate Dihyrate Na3C6H5O7 * 2 H2O
• Washed with HCl & Water
• Samples not examined under TEM
DACS Syn IV
• Processed directly using DACS• Formation of white precipitate very soon after
DACS reaction• No Surfactant• Ba Concentration ~0.4M (compared to NaOH)
DACS Syn IV TEM
• Quite abnormal
• High Cabonate
DACS Syn IV TEMtake two
Final Conclusions
• Final? Far from….• Precipitation-Dissolution Dominates Present
Literature– Project results can be interrupted to fit either model
• Nanoparticle synthesis in only water proves to be very difficult to process– Brownies in motion? Brownian motion?
– Present processing method does not account for Brownian motion (e.g. water or acid wash)
Nanoparticle Synthesis
• Solvothermal: Chen & Jiao– Barium alkoxide (H4Ba6(O)-(OCH2Ch2OCH3) &
Ti(OC4H9-n)4
• Using organic precursors or organic films: Lee, Yao, Imai, & Aksay– Titanyl acylate and barium acetate, fine but not nano
– Yielded Nanoparticles with barium titanium methoxypropanoxide (BaTi(OCH2CH(CH3)OCH3)6 on alkoxide-Kraton thin film
Future Work
• Standard Hydrothermal:– Determine affect of increasing Ba concentration not
changing BaCl2 mass
– Develop method of powder collection accounting for Brownian motion
• For DACS:– Retry direct reaction of DACS, post washing with alcohol – Adjust Ba:Ti to as close to 1:1 as possible– Perform entire reaction and post-reaction in nitrogen
atmosphere