Presentation Innovation 2010

8/7/2019 Presentation Innovation 2010

1/30

Synthesis and Photocatalytic Applications of

of TiO2 and its Nanocomposites

Pragati R. Thakur

Department of Chemistry

University of Pune


2/30

2

Applications of TiO2 in heterogeneous photocatalysis

Limitations of TiO2 as an efficient photocatalyst

Ways to surmount these limitations

Synthesis, characterization and applications of TiO2

Synthesis and applications of composites of TiO2

OUTLINE


3/30

3

HETEROGENEOUS PHOTOCATALYSIS

Complete mineralization of pollutants to environmentally harmless compounds.

Destruction of non-biodegradable refractory contaminants.

Operate at or slightly above ambient conditions.

Mechanism of Photocatalysis

e -

h +

O2.

Reduction

O2

OH.

Oxidation

H2O

OH. + Pollutants

CO2 + H2O

Schematic representation of the processes occurring in and

on semiconductor particles during the photo-catalytic mineralization

of organic molecules by oxygen.

hR P < 390 nm


4/30

4

THESE LIMITATIONS CAN BE SURMOUNTED BY

Composite photocatalyst preparation

Metal/Nonmetal doping

LIMITATIONS OF TiO2 AS AN EFFICIENT PHOTOCATALYST

Only active in near UV region

Charge carrier recombination

Low surface area for adsorption


5/30

5

SYNERGISTIC EFFECT OF CARBON NANOTUBES ON COMPOSIT PHOTOCATALYST

Applied Catal. B: Environ. 2005, 56, 305-312

Environ. Sci. Technol. 2008, 42, 4952-4957

AdsorbentDispersing agent

Large surface area

JMaterial Sci. 2008 43, 2348-2355.


6/30

6

Preparation of TiO2 nanoparticles

(i) Microemulsion method

(ii) Sol gel method

Characterization of as prepared TiO2 nanoparticles by XRD, FTIR,

DRS, TG-DTA, BET, SEM and TEM.

Application of as prepared TiO2 nanoparticles for the

photocatalytic degradation of targeted pollutant Methyl Orange.

Experimental


7/30

7

TiO2/activated carbon (TA) composite has been prepared with

enhanced photocatalytic activity by a very simple mechanical

grinding method, which could preserve the respective initial surface

states of the individual solid constituents, giving a synergistic effect.

The as prepared composite was characterized by SEM, XRD, BET

surface area, UV-visible absorbance spectroscopy and Raman

spectroscopy.

p-Nitrophenol was used as target pollutant to test the photocatalytic

activity.

ACTIVATED CARBON-TiO2 COMPOSITE

Synergistic effect of Adsorption and Photocatalysis


8/30


9/30

9

XRD ofMerck TiO2, AC-200 and TA-200(5:1)

Raman spectra

UV-Visible diffuse reflectance

CHARACTERIZATION OF ACTIVATED CARBON-TiO2 COMPOSITE


10/30

10


11/30

11

Synthesis of Silver Doped TiO2 NanoparticlesSynthesis of Silver Doped TiO2 Nanoparticles

TiOTiO22 nanoparticles were prepared by solnanoparticles were prepared by sol--gel method using Titaniumgel method using Titanium

tetraisotetraiso--propoxide as precursor.propoxide as precursor.

Silver was then photodeposited on the TiOSilver was then photodeposited on the TiO22 Nanoparticles byNanoparticles by

Photodeposition method.Photodeposition method.

Photocatalytic activity was determined by degradation of Methyl OrangePhotocatalytic activity was determined by degradation of Methyl Orange

Dye as target pollutant.Dye as target pollutant.


12/30

12

a. Ag-TiO2 b. TiO2 c. Merck TiO2

Characterization of Prepared TiO2 and AgCharacterization of Prepared TiO2 and Ag--TiO2TiO2

The XRD pattern shows theThe XRD pattern shows the

presence of pure anatasepresence of pure anatase

phase in TiOphase in TiO22 ..

Solid UVSolid UV--Visible absorbance spectraVisible absorbance spectra


13/30

13

SEM images of TiOSEM images of TiO22 and Agand Ag--TiOTiO22

TEM images of TiOTEM images of TiO22 and Agand Ag--TiOTiO22

Characterization of Prepared TiOCharacterization of Prepared TiO22 and Agand Ag--TiOTiO22


14/30

14


15/30

15

AeratorPump

Magnetic Stirrer

Water OutletWater Inlet

Sample Aliquot

Mercury Vapor Lamp

Quartz Tube

EXPERIMENTAL SET UP FOR PHOTOCATALYSIS


16/30

16

TiO2 Samples BET Surface Area in m2/g

TiO2 microemulsion method

TiO2 Sol-gel method

27.012 0.138 m2/g

150 m2/g


17/30

200 300 400 500 600 700 8000.0

0.2

0.4

0.6

0.8

1.0

Absorbance

wavelength in nm

DiffuseReflectance Spectra ofRT-TiO2 Nanoparicles


18/30


19/30

Spectral changes occurred during the photodegradation of MO dye

350 400 450 500 550 600-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 min.

30 min.

60 min.

90 min.

120 min.

150 min.

Absorbance

wavelength in nm

Spectral changes occurred during

the photodegradation of MO at RT

3 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0

0 . 0 0

0 . 0 5

0 . 1 0

0 . 1 5

0 . 2 0

0 . 2 5

0 . 3 0

0 . 3 5

0 . 4 0

0 m in.

30 m in .

60 m in .

90 m in .

120 m in .

150 m in .

A

bsorbance

w a v e l e n g t h i n n m

Specta l changes occurred dur ing

the photod egradat ion of M O at RT

T iO2(w ithout surfactant )

3 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0

0 . 0 0

0 . 0 5

0 . 1 0

0 . 1 5

0 . 2 0

0 . 2 5

0 . 3 0

0 . 3 5

0 . 4 0S p e c t r a l c h a n g e s o c c u r r e d d u r i n g

t h e p h o t o d e g r a d a t i o n o f

M O for w itho ut T iO2

0 m in .

3 0 m in .

6 0 m in .

9 0 m in .

1 2 0 m in .

1 5 0 m in .

A

bsorban

ce

w a ve le n g th in n m


20/30

COD graph of photodegradation of TiO2

0 30 60 90 120

0

10

20

30

40

50

60

70

80

90

%C

D

ti

i

i

i

.

0 30 60 90 120

0

10

20

30

40

%C

D

ti

i i i .

80% COD reduction of TiO2(with

surfactant)41% COD reduction of TiO2 (without

surfactant)


21/30

SEM image of TiO2


22/30

Photocatalytic degradation ofMO dye using TiO2

0 20 40 60 80 100 120 140 1600.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

TiO2

with surfactant

TiO2

without surfactant

without TiO2

/

0

Irradiation time in min.


23/30

XRD pattern of TiO2

2 0 3 0 4 0 5 0 6 0 7 0 8 0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

B

I

t

ityi

.

U


24/30

FTIR of TiO2

40 00 3 50 0 30 00 25 0 0 20 00 15 0 0 10 00 5 0 0

10

15

20

25

30

35

40

45

B

%

r i-1


25/30

TG-DTA plot of prepared TiO2


26/30

Results and discussion

TiO2 nanoparticles have been synthesized by a reverse microemulsion process using TiCl4

as a precursor and sol-gel method. XRD study shows pure rutile phase for TiO2 prepared by microemulsion method and pure

anatase phase by using sol-gel method.

FTIR study shows strong band for surfactant and broad band corresponding to surface

hydroxyl group on TiO2

TGA shows observable weight loss about 19% and exhaust of HCl gas from the precursor

which is confirmed by chloride test and DTA shows decomposition of hydrated oxide. From DRS calculated band gap energy is 3.0 eV.

BET Analysis shows surface area of microemulsion mediated TiO2 is 27.012 0.138 m2/g

and 150 m2/g for sol-gel method.

TEM images shows spherical shape of TiO2 for both methods.

HigherPhotocatalytic degradation of MO dye has been found for TiO2 prepared by using

surfactant as compared to TiO2 prepared without surfactant.


27/30

27

REFERENCES

1. Wang Y., Jiang Z., Synthesis of anatase titania-carbon nanotubes nanocomposites with enhanced photocatalytic activity

through a nanocoating-hydrothermal process. J NanoparticleRes. 2007, 9, 1087-1096.

2. Yan J., Song H., Yang S., Yan J., Chen X., Preparation and electrochemical properties of carbon nanotubes loaded with

Ag and TiO2 nanoparticle for use as anode material in lithium-ion batteries. Electrochimica Acta. 2008, 53, 6351-6355.

3. Yu Y., Yu J.C., Chan C.Y., Che Y. K., Zhao J.C., Ding L., Ge W. K., Wong P.K., Enhancement of adsorption andphotocatalytic activity of mesoporous TiO2 by using carbon nanotubes. Appl. Catal. A: Gen. 2005, 289, 186-196.

4.Mishra A., Banerjee S., Sushanta K.M., Graeve O.A.,MishraM., Synthesis of carbon nanotube-TiO2 nanotubular

material for reversible hydrogen storage J. Nanotech. 19, 2008, 445607.

5. Yu H., Quan X., Chen S., Zhao H., TiO2-Multiwalled carbon nanotube heterojunction arrays and their charge

separation capability, J. Phys. Chem. C, 2007, 111, 12987-12991.

6. Rim S., Vittal R., Kim K. J., Incorporation of funtionalized single wall carbon nanotubes in dye sensitized TiO2 solar

cells, Langmuir, 2004, 20, 9807-9810.


28/30

28

1.EI-Sharkawy E.A.,Soli

a

A.Y.,Al-A

er K.M.,Co

parative study for the re

oval of

ethyle

e blue via adsorptio

a

d photocatalytic degradatio

, J.Colloide and Int

1.Syoufia

A.,Nakashi

a K., Deradatio

of

ethyle

e blue i

aqueous dispersio

of hollow tita

ia photocatalyst:Study of reactio

e

ha

ce

e

t by various electro

scave

gers,J.Colloid.Interface.Sci.,317,507(2008)

Zha

g T.,Oya

a T., Aoshi

a A., Hidak H., ZhaoJ., Serpo

e N., Photooxidative N-de

ethylatio

of

ethyle

e blue i

aqueous TiO2

dispersio

s u

der UV irradiatio

,J.Phot

(2001)

1.Choy W.K.,Chu W.,The use of oxyhaloge

i

photocatalytic reactio

to re

ove o-chloroa

ili

e i

TiO2dispersio

,Chemosphere.,66,2106 (2007)

1.tos J.N.R.D.,Souza D.S.,Souza E.E.S.,Decolourisatio

effect of Vat Gree

01 textile dye a

d textile wastewater usi

g H2O

2/UV process, J.Photochem.and

Photobiol.A:Chem.,186,125(2007)

1.Schra!

k S.G.,Sa!

tos J.N.R.D.,Souza D.S.,Souza E.E.S.,Decolourisatio!

effect of Vat Gree!

01 textile dye a!

d textile wastewater usi!

g H2O

2/UV process, J.Photochem.and


29/30


30/30

30

Thank You !

Documents

Presentation Innovation 2010