Tio2-sio2 Thin

Prince of Songkla University

Contact Angle of Glass Substrate Coated with TiO2/SiO2 Thin Film Jiraporn Damchan1, Lek Sikong1*, Kalayanee Kooptarnond1, Sutham Niyomwas2

1Department

of Mining and Materials Engineering Faculty of Engineering *NANOTEC Center of Excellence at Prince of Songkla University 2Department

of Mechanical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, 90112

Outline „ „ „ „ „ „

Introduction Objective Experiment procedure Result and discussion Conclusion Acknowledgements

Photocatalyst Applications

www.concretedecor.net

Photocatalyst, TiO2 (http://staff.aist.go.jp)

The crystal structure of rutile.(Tetragonal)

Anatase (Tetragonal)

Brookite (Orthorhombic)

Anatase is the best photocatalytic activity

Mechanism of the decomposition of organics 3.2 eV

www.nanobest.co.kr

Chemical reduction

TiO 2 + h *ν → e − cb + h + vb

O

2

+ e

H 2O + h

−

+

cb

→ O •

vb

− 2

→ OH + H

+

Objective To study the effect of amount of SiO2 on Photocatalytic activity and Hydrophilic of glass substrate coated with TiO2 film catalyst

Parameters „ „ „ „

Calcination temperatures at 500°C Content of SiO2 (5 -20mol%) Photocatalytic reaction time is 1-6 h Contact angle of between water and composite film in conditions dark place and 30 minute UV irradiation

Experimental „ „

„ „

Sol – Gel Method for coating agent synthesis Spin Coating Process for coated glass substrate „ Spin speed = 1700 rpm for 30 sec. „ Glass substrate 10x10x0.3 cm Photocatalytic reaction time 1-6 h , λ = 664 nm Contact angle measurement, CAM-PLUS Tantec

Synthesis of TiO2/SiO2 using sol-gel method TTIP

TEOS

C2H5OH

Mix solution

TiO2 sol

Spin coating on Soda lime glass

Thin film

Dried and calcined

Photocatalytic reaction test

powder

XRD,SEM ,AFM

Spin Process

Spin speed 1700 rpm for 30 sec

Dried and calcined

TiO2/SiO2 film

Substrate

Photocatalytic Reaction Test

black light 50 W in dark chamber - Irradiation time 1-6 h -Methylene blue = 1x10-5 M

-

Soda lime glass

Results and Discussion

Morphology of film Pure TiO2 film

Particle size :

R = 3.766 nm

5%SiO2/TiO2 film

R = 0.7279 nm

TiO2>5%SiO2/TiO2

Surface roughness (R): Pure TiO2 > 5%SiO2/TiO2

Effect of SiO2 content

XRD patterns

Crystallite size of TiO2/SiO2 samples at 500ºC Content of SiO2 (mol %)

Crystallite size (nm)

0(pure TiO2)

23.64

5

13.47

10

8.27

15

9.18

20

9.19

Amount of SiO2 Crystallite size

SiO2 prevents the formation of anatase crystalline and grain growth

Contact angle of composite thin film UV light irradiation and in dark place (500oC)

Contact angle (degree)

Effect content of SiO2 contact angle of composite thin film after irradiation UV light (500oC) uncoated

pure TiO2

5%SiO2/TiO2

10%SiO2/TiO2

15%SiO2/TiO2

20%SiO2/TiO2

50 45 40 35 30 25 20 15 10 5 0 0

5

10

15

20

Time after irradiation (min)

25

30

Photocatalytic Decolour of MB 20%SiO2

UV 6 h

PureTiO2

pureTiO2

5%SiO2/TiO2

Degradation of MB Pure TiO2

5%SiO2/TiO2 =73.3%

10%SiO2/TiO2

15%SiO2/TiO2

20%SiO2/TiO2

80

Degradation of MB (%)

Pure TiO2 = 41.5%

5%SiO2/TiO2

5%SiO2/TiO2

70 60 50 40

PureTiO2

30 20 10 0 0

1

2

3

4

Irradiation time (h)

5

6

7

Conclusion ¾

SiO2/TiO2 show photocatalytic activity higher than pure TiO2 by adding 5mol% SiO2 to the film ,percent of degradation of MB ¾Pure

TiO2 films = 42 % ¾5mol% SiO2 films = 73%

Conclusion (Cont.) „

Hydrophilic of films Content SiO2

20

hydrophobic

15

hydrophilic

10

hydrophobic

5

hydrophilic 0

Acknowledgements The financial support for this research by „

Department of Mining and Materials Engineering ,Prince of Songkla University

„

NANOTEC Center of Excellence at Prince of Songkla University

„

Thailand and partially financial from National Research Council of Thailand (NRCT)