PHƯƠNG PHÁP SOLGEL TIO2 - CdS

PHƯƠNG PHÁP SOLGEL
TiO2-CdS
Nguyễn ĐằngTrai
I. TẠO SOL TiO
2
/CdS
 CdS: II-VI
 TiO
2
: 3.21 eV to 3.4 eV
 CdS : 2.42 eV
 Các hóa chất cần thiết:
◦ Titanium (IV) isopropoxide.
◦ Cadmium acetate hydrate.
◦ Ethanol.
◦ H
2
S.
◦ HCl.
Titanium (IV) isopropoxide
 Ti[OCH(CH
3
)
2
]
4

 Colorless liquid
 M = 284 g/mol
 d = 0.937 g/cm
3

 Melting, boiling: 18–20 °C, 232 °C
Cadmium acetate hydrate
 (CH
3
CO
2
)
2
Cd . xH
2
O
 (CH
3
CO
2
)
2
Cd . 2H
2
O
◦ White crystals
◦ M = 266.529 g/mol
◦ d = 2.01 g/cm
3

◦ Melting point: 130°C
◦ Soluble in water, ethanol.
Ethanol
 C

2
H
5
OH
 Colourless liquid
 M = 46.07 g/mol
 d = 0.789 g/cm
3

 Melting, boiling: −114 °C, 78 °C
Hydro sulfua
 H
2
S (ít tan trong nước)
 Colorless gas.
 M = 34.082 g/mol
 d = 1.363 g/l
 Melting, boiling: -82.30 °C, -60.28 °C
 Solubility in water:
◦ 0.4 g/100 ml (20 °C)
◦ 0.25 g/100 ml (40 °C)
 Điều chế H
2
S:
◦ Không điều chế trong công nghiệp.
◦ HI+SO
2
H
2
O+H

2
S+I
2
◦ Trong phòng thí nghiệm:
FeS + 2HCl  FeCl
2
+ H
2
S



Titanium (IV) isopropoxide  Ethanol
(5ml : 25ml)
Ethanol  Cadmium acetate
(25ml : 0.5g)
one drop of
0.5M HCl
SOL
TiO2/CdS
Stir in an ice bath
Mix in ice bath Colorless
Transparent
saturated H2S water
solution
Add slowly
Until:
Yellow white
Semi-transparent
II.TẠO SOL CdS

Colour: yellow to orange
d = 4830 kg m
-3

1. Cách 1:
 Các hóa chất cần thiết:
◦ Polyethylene glycol (PEG)
◦ Cadmium nitrate (cung cấp Cd)
◦ Thiourea (cung cấp S)
◦ Ethanol
◦ Acetic Acid



Polyethylene glycol
 H(OCH
2
CH
2
)
n
OH
Cadmium nitrate
 Cd(NO
3
)
2
 White crystals
 M = 236 g/mol
 d = 3.60 g/cm

3

 Mp: 350 °C


Thiourea
 SC(NH
2
)
2

 White solid
 M = 76 g/mol
 d = 1.405 g/ml
 Mp: 182 °C
Ethanol
 C
2
H
5
OH
 Colourless liquid
 M = 46.07 g/mol
 d = 0.789 g/cm
3

 Melting, boiling: −114 °C, 78 °C
Acetic acid
 CH
3

COOH
 Colourless liquid
 M = 60 g/mol
 d = 1.049 g/cm
3

 Mp, Bp: 16.5 °C, 118.1 °C
Polyethylene glycol  Ethanol
(0.6 ml  8.9 ml)
Acetic Acid
(0.5 ml)
Stir
Continue stir
(1-hour)
Cadmium nitrate (0.3 mol/l)
Thiourea (0.3, 0.4 , 0.6 mol/l)
 Ethanol
Stir (1-hour)
Add slowly
SOL
Stir
(5-6 hours)
2. Cách 2:
 Các hóa chất cần thiết:
◦ Cadmium acetate dihydrate (CAD)
◦ Thiourea (Tu)
◦ 1-Thioglycerol (TG)
◦ N,N-dimethylformamide (DMF)
Cadmium acetate hydrate
 (CH

3
CO
2
)
2
Cd . 2H
2
O
◦ White crystals
◦ M = 266.529 g/mol
◦ d = 2.01 g/cm
3

◦ Melting point: 130°C
◦ Soluble in water, ethanol.
1-thioglycerol
 HSCH
2
CH(OH)CH
2
OH
 M = 108 g/mol
 d = 1.25 g/mL at 25 °C


Thiourea
 SC(NH
2
)
2

 White solid
 M = 76 g/mol
 d = 1.405 g/ml
 Mp: 182 °C
N,N-dimethylformamide
 (CH
3
)
2
NC(O)H
 Clear liquid
 M = 73 g/mol
 d = 0.944 g/cm
3


Mp, Bp: -61 °C, 153 °C



TG
CAD
Tu
DMF  Water
(3:1 vol)
CdS sol
20 mL
3. Cách 3:
 Các hóa chất cần thiết:

◦ Cadmium nitride
◦ Ammonium thiocyanate
◦ n-Buthanol
Cadmium nitride
 Cd
3
N
2

 Black powder
 M = 365 g/mol

 3Cd(NH
2
)
2
(s) (180°C) → Cd
3
N
2
(s) +
4NH
3
(g)
Ammonium thiocyanate
 NH
4
SCN
 Crystalline solid
 M = 76 g/mol

 d = 1.305 g/cm
3


Mp, Bp: 149.5 °C, 170 °C

n-Buthanol
 C
4
H
10
O
 Colourless liquid
 M = 74 g/mol
 d = 0.8098 g/cm
3

Mp, Bp: −89.5 °C, 117.7 °C