PHOTOCATALYTIC AND ELECTROCHEMICAL PROCESSES FOR GENERATION OF HYDROGEN AND DECONTAMINATION OF WATER M. Sathish CYD01014 20-7-06.

PHOTOCATALYTIC AND ELECTROCHEMICAL PROCESSES FOR GENERATION OF HYDROGEN

AND DECONTAMINATION OF WATER

M. Sathish

CYD01014

20-7-06

Photocatalytic generation of hydrogen – CdS nanoparticles

Photocatalytic decontamination of water – anion doped visible light active TiO2 photocatalyst

Electrolytic generation of hydrogen – compartmentalized electrolytic cell

Electrolytic decontamination of water – compartmentalized electrolytic cell

CONTENTS

2

HYDROGEN PRODUCTION BY WATER SPLITTING

Processes Drawback

Photocatalytic decomposition – Suitable catalyst

Electrolytic decomposition – Over potential

Thermal decomposition – High temperature

Biological decomposition – Infancy

3

MECHANISM OF PHOTOCATALYTIC PROCESSES

4

high surface area

presence of more number of surface states

wide band gap

position of the VB & CB edge

CdS – appropriate choice for the hydrogen production

eV

ADVANTAGES OF SEMICONDUCTOR NANOPARTICLES

5

PREPARATION, CHARACTERIZATION AND PHOTOCATALYTIC HYDROGEN PRODUCTION BY CdS

NANOPARTICLES

6

CHAPTER - 3

PREPARATION OF CdS NANOPARTICLES

1 g of Zeolite (HY, H, HZSM-5)

1 M Cd(NO3)2 , stirred for 24 h, washed with water

Cd / Zeolite

1 M Na2S solution, stirred for 12 h, washed with water

CdS / Zeolite

48 % HF, washed with water

CdS Nanoparticles

7

XRD PATTERN OF CdS

8M. Sathish, B. Viswanathan, R. P. Viswanath Int. J. Hydrogen Energy, 31 (2006) 891

Debye Scherrer Equation

d SPACING AND CRYSTALLITE SIZE

0.89

cosT

= diffraction angle T = Crystallite size = wave length = FWHM

9

d-spacing (Å)

Catalyst(0 0 2) (1 0 1) (1 1 2)

Crystallite

Size(nm)

CdS (bulk) 1.52 1.79 2.97 21.7

CdS (bulk)

(HF treated)

1.52 1.79 2.93 21.7

CdS-Y 1.53 1.79 2.96 8.8

CdS- 1.52 1.78 2.93 8.6

CdS-Z 1.52 1.79 2.97 7.2

UV –VISIBLE SPECTRA OF CdS SAMPLES

Samples Band Gap (eV)

CdS – Z

CdS – Y

CdS -

Bulk CdS

2.38

2.27

2.21

2.13


PHOTOCATALYTIC PRODUCTION OF HYDROGEN

35ml of 0.24 M Na2S and 0.35 M Na2SO3 in Quartz cell

0.1 g CdS400 W Hg lamp

N2 gas purged before the reaction and constant stirring

Hydrogen gas was collected overwater in the gas burette

11

AMOUNT OF HYDROGEN EVOLVED BY CdS PHOTOCATALYST


SCANNING ELECTRON MICROGRAPHS

13

CdS-Z CdS-Y

CdS- CdS- bulk

Activity of the catalyst is directly proportional to work function of the metal and M-H bond strength.

PHOTOCATALYTIC HYDROGEN EVOLUTION OVER METAL LOADED CdS NANOPARTICLES

14

MetalRedox

potential(E0)

Metal- hydrogen bond energy (K cal mol-1)

Work function

(eV)

Hydrogen evolution rate*(µmol h-1 0.1g-1)

PtPdRhRu

1.1880.9510.7580.455

62.864.565.166.6

5.655.124.984.71

60014411454

HYDROGEN PRODUCTION ACTIVITY OF METAL LOADED CdS PREPARED FROM H-ZSM-5

*1 wt% metal loaded on CdS-Z sample. The reaction data is presented after 6 h under reaction condition.


250 ml of 5 mM Na2S solution

250 ml of 1 mM Cd(NO3)2

Rate of addition 20 ml / h

Ultrasonic waves

= 20 kHz

The resulting precipitate was washed with distilled water

until the filtrate was free from S2- ions

PREPARATION OF MESOPOROUS CdS NANOPARTICLE

BY ULTRASONIC MEDIATED PRECIPITATION

16

The particle size is calculated using Debye Scherrer Equation

The average particle size of as- prepared CdS is 4-6 nm

UV-VISIBLE SPECTRA & X- RAY DIFFRACTION PATTERN

M. Sathish and R. P. Viswanath. Chemistry letters, 36 (2007) 94817

The absorption on set of CdS-U shows blue shift compared to bulk CdS particles

The specific surface area and pore volume are 94 m2/g and 0.157 cm3/g respectively

The adsorption - desorption isotherm – Type IV (mesoporous nature)

Mesopores are in the range of 30 to 80 Å size

The maximum pore volume is contributed by 45 Å size pores

N2 ADSORPTION - DESORPTION ISOTHERM

18M. Sathish and R. P. Viswanath. Chemistry letters, 36 (2007) 948

The growth of fine spongy particles of CdS-U is observed on the surface of the CdS-U

The CdS-bulk surface is found with large outgrowth of CdS particles

The fine mesoporous CdS particles are in the nanosize range

The dispersed and agglomerated forms are clearly observed for the as-prepared CdS-U

CdS - Bulk

TEM SEM

ELECTRON MICROGRAPHS

19

CdS-UCdS-U

Metal CdS-U CdS-Z CdS

bulk

Literature*

-

Rh

Pd

Pt

73

320

726

1415 (32 ml)

68

114

144

600

45

102

109

275

60

96

140

376

1 wt % Metal loaded CdS – U is 2-3 times more active than

the CdS-Z

PHOTOCATALYTIC HYDROGEN PRODUCTION

Na2S and Na2SO3 mixture used as sacrificial agent

Amount of hydrogen (µM/0.1 g/h)

20M. Sathish and R. P. Viswanath. Catalysis Today, 129 (2007) 421

The CdS nanoparticles show higher photocatalytic activity than the bulk particles

The size, surface area and morphology of the particles play an important role on photocatalytic activity

Pt loading on photocatalyst enhances the hydrogen production activity due to its unique properties

Pt loaded mesoporous CdS nanoparticle - promising catalyst for photocatalytic hydrogen production using sunlight

SUMMARY

21

PREPARATION, CHARACTERIZATION OF VISIBLE LIGHT ACTIVE N-DOPED AND N, S CO-DOPED TiO2

22

CHAPTER - 4

DOPING

CATIONS ANIONS

Photocorrosion of doped element

Increases carrier recombination center

Introduced oxygen vacancy leads to the formation of lower energy levels

Decrease in the electron mobility in the bulk due to localization

Orbital overlapping between the doped element and oxygen alters the valence and conduction band position

Formation of energy levels closer to the VB and CB

No photocorrosion

E.g., N, S, P & B

LimitationsAdvantages

23

EFFECTS OF NITROGEN DOPING IN TiO2

Addition of nitrogen increases the size of the bondorbitals, decreasing the energy bandgap

Energy TiO2 BondOrbitals

TiO2-xNx BondOrbitals

Conduction Band

Ti d + (O2p) Ti d +O2p +N2p)

Valence Band

N2p + O2p

(O 2P + Ti d) + (Ti d)

Ti d

O 2p

Ti dN2pO2p

Eg = 3.2 eV

Eg = 2.5 eV

24

PREPARATION OF N - DOPED TiO2

Ti2S3

(NH4)XTiSX

pH was adjusted to 8.5 by slow addition of ~10 ml liq NH3

Calcined for 4 h in air at 400, 500 and 600 ºC

50 ml of 15 % TiCl3 + 50 ml of 0.5 M Na2S

Method - I

25

Only Anatase phase upto 600 oC No change in crystal lattice

~ 120 nm red shift in onset absorption for N - doped TiO2

UV-VISIBLE ABSORPTION SPECTRA AND X-RAY DIFFRACTION PATTERN

26M. Sathish, B. Viswanathan, R.P. Viswanath and C.S. Gopinath, Chem. Mater., 17 (2005) 6349

XPS SPECTRA OF N−TiO2 AND TiO2

Shift in the Ti 2p3/2 binding energy to lower energy due to the N- doping on TiO2 lattice

Lower electronegativity of N than O, reduce the positive charge on Ti in the TiO2 lattice - Covalency increased

N 1S peak at 398.2 eV shows – low negative

charge3

98

.2 e

V

53

0 e

V

45

8.5

eV

4

59

.3

NitrogenBinding

energy (eV)

N-TiO2 398.2

TiN (or) chemisorbed

397

NO or NO2 > 400

27M. Sathish, B. Viswanathan, R.P. Viswanath and C.S. Gopinath, Chem. Mater., 17 (2005) 6349

N replaces the oxygen in the TiO2 lattice , which results O-Ti-N environment

Peak at 530 eV due to lattice Oxygen in TiO2

Peak at 531.5 eV due to the oxygen present in the O-Ti-N environment

Due to the more covalent nature -

O-Ti-N environment compare to O-Ti-O environment, this additional peak appears at higher energy region

28

PREPARATION OF N - DOPED TiO2

Titanium−Salen Complex

Vacuum heating at 400 ºC, 6 h

Calcination in N2 atmosphere for 2 h @ 400 ºC then in air for 2 h @ 400 ºC

N−TiO2

Ti-Salen complex

CHO

OH+

Ethanol,RT Ti (OiPr)4,DCM

RTH2N NH2 OH

N N

HO O

N N

OTi

PrOi OiPr

2

Method- II

29

Presence of Anatase phase and peak broadening observed

No change in crystal lattice

~50 nm shift in the onset absorption for N - doped TiO2

X-RAY DIFFRACTION PATTERN AND UV-VISIBLE ABSORPTION SPECTRA

30M. Sathish, B. Viswanathan and R. P. Viswanath. Int. J. Nanoscience, 6 (2007) 137

Shift in the Ti 2p3/2 binding energy to lower energy due to the N- doping on TiO2 lattice

Lower electronegativity of N than O, reduce the positive charge on Ti in TiO2 lattice Peak at 400 eV for N 1s N in neutral or slight negative charge

40

0 e

V

53

0 e

V

XPS SPECTRA OF N - TiO2 AND TiO2


Average particle size of the N−doped TiO2 = 14 nm

Peak at 529.8 eV corresponds to the Oxygen 1s in the TiO2 lattice

Peak at 531.1 eV shows the presence of O in O-Ti-N environment


Catalyst : N - TiO2 and commercial TiO2 (Degussa P25)

Experimental condition:

25 mg of catalyst + 25 ml of 110 ppm methylene blue solution

Filters: monochromatic filters @ 365, 405, 436, 546 nm

400W Hg lamp @ fixed wavelength for 30 min

Method - I Method - II

DECOMPOSITION OF METHYLENE BLUE IN THE VISIBLE REGION

33

PREPARATION OF N- DOPED TiO2

Melamine ( 2:1 ethanol: water mixture)

Ti(iOPr)4 in ethanol3:1 molar ratio

Ti-Melamine sol-gel

Stirred for 24 h, then kept for 4 days

Washed with hot water, calcined at 400, 500, 600, 700

oC

34

UV-VISIBLE SPECTRA & X- RAY DIFFRACTION PATTERN

No change in the d values- indicates no change in the crystal lattice due to doping of N in the TiO2 lattice

M. Sathish, B.Viswanathan and R. P. Viswanath, Appl Catal B, 74 (2007) 30835

Broad peak centered around 398.4 eV – presence of N-Ti-O environment

A peak around 396.2 eV shows the presence of Ti- N bonding

401.4 eV peak is due to adsorbed nitrogen on TiO2 & 400 eV is due to adsorbed N-containing organic species in the grain boundary

N 1s

X- RAY PHOTOELECTRON SPECTROSCOPY

36

The N-doped TiO2 particles calcined at 400 oC exhibits spherical and leaves like morphology

SCANNING ELECTRON MICROGRAPH

Calcination Temperature

(oC)

Specifice

surface area

(m2/g)

Crystallite size (nm)

Crystalline nature

400

500

600

700

33

11

-

-

30

36

42

45

Anatase

Anatase

Anatase & rutile

Anatase & rutile

37

TEM measurement shows that the particle are in the range of 30 nm in size

Spherical type particles can also be seen in TEM clearly

TEM

50 nm

100 nm

100 nm

38

VISIBLE LIGHT PHOTOCATALYTIC DECOMPOSITION OF METHYLENE BLUE

Experimental Condition

Catalyst = 0.1 g TiO2 (N- TiO2 and P25)

Solution: 50 ml of 50 ppm methylene blue solution

Light source : 400 W Hg lamp

Filter : HOYA – L – 42 (UV cutoff filter)

Time : 3 h

The mixture was stirred for 15 min in the dark to attain adsorption equilibrium

The samples were collected every 30 min and UV-Visible absorbance was measured at 660 nm (max of methylene blue)

39

Higher photocatalytic activity was observed for N-doped TiO2 compared to P25 catalyst in the visible region

Highest photocatalytic activity was observed for N-TiO2 calcined at 500 oC

Above 500 oC, the activity decrease due to loss of N in the N-TiO2 sample

UV-visible absorbance spectra also supports the above observation

40M. Sathish, B.Viswanathan and R. P. Viswanath, Appl Catal B, 74 (2007) 308

PREPARATION OF N, S CO-DOPED TiO2

CHO

OH

NH2

SH

N

OH

SH+Ethanol,RT Ti (OiPr)4,DCM

RT

S

N

O

S

N

O

Ti

NH2

SH

Ti (OiPr)4,DCM

RT

HN

S

Ti

NH

S

OiPr

OiPr

TB

TS

TS/TB complexes calcined in vacuum at 400 0C for 12h, followed by calcination in N2 at 400 0C for 6h

Finally calcined in air at required temperature (between 400 and 600 0C) to remove carbon completely.

41

A shift in the on set optical absorption of about 0.21 eV for N, S doped TiO2

than Pure TiO2

OPTICAL ABSORPTION SPECTRA OF N, S CO-DOPED TiO2

42M. Sathish, R.P. Viswanath and C.S. Gopinath, Chem. Mater., (communicated)

Particle size variation between 8 -16 nm observed

TEM OF N, S DOPED TiO2

43M. Sathish, R.P. Viswanath and C.S. Gopinath, J Nanoscience and Nanotechnology (Accepted)

N and N,S-co-doped systems show a decrease in Ti 2p BE

Oxidation state of S is S 6+ (as in sulfate) and N as in NO

Oxidation state of N is different on N-TiO2 and N,S-TiO2

STATE OF N AND S ON N,S-CO-DOPED TiO2 -XPS

44

PHOTOCATALYTIC DECOMPOSITION OF METHYLENE BLUE ON N, S CO-DOPED TiO2 SURFACE

45M. Sathish, R.P. Viswanath and C.S. Gopinath, J Nanoscience and Nanotechnology (Accepted)

N-doping on TiO2 via chemical process shows more red shift than the decomposition of N containing Ti precursor process

XPS results show, Nitrogen replaces the Oxygen in TiO2 lattice and formation N-Ti-O environment – also increases the covalent nature Ti–O bond

N-TiO2 shows higher photocatalytic activity than TiO2 (degussa P 25)

in the visible region

N, S co-doped TiO2 shows more activity than N-doped TiO2

SUMMARY

46

STUDIES ON THE ELECTROLYTIC GENERATION OFHYDROGEN – DESIGN OF COMPARTMENTALIZED CELL

CHAPTER - 5

Reaction E0 (V)

In acidic medium

2H + + 2e- ⇌ H2 0.000

O2 + 4e- + 4H + 2H⇌ 2O 1.229

In alkaline medium

O2 + 4e- + 2H2O 4OH ⇌ - 0.401

2H2O + 2e- 2OH⇌ - + H2 −0.828

Medium Over potential (V)

H2 O2

Acidic ~ 0.05 ~ 0.5

Alkaline ~ 0.05 - 0.3 ~ 1

For Pt electrodes

HYDROGEN AND OXYGEN EVOLUTION POTENTIAL

48

S. NoMedium Decomposition

potential (V)

1 HNO3 1.69

2 H2SO4 1.67

3 HCl 1.31

4 NaOH 1.69

5 KOH 1.67

6 NH3(aq) 1.74

Decomposition potential of water in different media

1. Nature of the electrolyte or medium

2. Temperature

3. pH

FACTORS AFFECTING THE DECOMPOSITION POTENTIAL

49

INFLUENCE OF TEMPERATURE ON THE REVERSIBLE POTENTIAL FOR WATER ELECTROLYSIS

50

INFLUENCE OF pH ON THE REVERSIBLE POTENTIAL FOR WATER ELECTROLYSIS

The hydrogen evolution potential at pH = 0 and 14 are 0 and -0.828 V

The oxygen evolution potential atpH = 0 and 14 are 1.229 and 0.401 V

The overall reversible decomposition potential at any given pH will be equal to 1.229 V

Separation of anode and cathode with different (pH) electrolytes will alter the decomposition potential

51

pH

1.229

0.401

14

−0.828

Potential (V) Potential (V)

0

COMPARTMENTALIZED ELECTROLYTIC CELL

1. Cathode 4. Catholyte

2. Anode 5. Anolyte

3. Chemically treated separator

52

THE COMMON AND COMPARTMENTALIZED ELECTROLYTIC CELL

In compartmentalized electrolytic cell the cell current for an applied potential of 1.2 V is 1.56 mA

In common electrolytic cell the cell current for an applied potential of 1.2 V is 0.01 mA

53R. P. Viswanath and M. Sathish. Indian Patent Filed 810/Che/2003

The decomposition potential is ~ 1.0 V in the compartmentalized electrolytic cell, whereas ~ 1.8 V for the common electrolytic cell

At 1.8 V the compartmentalized cell shows higher cell currentthan the common electrolytic cell

Pt/ Anolyte // Catholyte / Pt

1.23

V

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2-2

0

2

4

6

8

10

12

14

16

Ce

ll c

urr

en

t (m

A)

Applied Potential (V)

Our cell Common cell with Acid Common cell with Alkali

54R. P. Viswanath and M. Sathish. Indian Patent Filed 810/Che/2003

EFFECT OF ELECTROLYTE CONCENTRATION ON THE CELL CURRENT

Pt / electrolyte / Pt

The concentration of the electrolytes play a major role on electrolysisboth in acid and alkaline electrolytic cell

55

Optimum concentration of anolyte and catholyte is 1N

R. P. Viswanath and M. Sathish. Indian Patent Filed 810/Che/200356

RATE OF HYDROGEN AN OXYGEN PRODUCTION AT AN APPLIED DC POTENTIAL OF 1V

The volume ratio of H2 and O2 evolved at the cathode and anode is 2 : 1

The products analyzed using gas chromatography

No side reaction or side products observed

57

Co and Ni are deposited over Pt and Ti electrode by electrodeposition method from their corresponding metal salts

Co and Ni on Pt and Ti electrode shows higher activity than pure Ti and Pt electrodes – high surface area

NATURE OF THE ANODE

58

MULTIPLE ELECTROLYTIC CELL

All the cells are connected in parallel and the anolytes and catholytes are passed from one cell to another cell

59

The net cell current is increased when three cells are connected in parallel

(-) (+)

H2 O2

Advantages

1. The distance between the anode and cathode is reduced

2. Variety of other separators can be used

3. The diameter of the separators can be varied

4. High cell current can be obtained60

Hydrogen and oxygen has been produced at 1.0 V by compartmentalized electrolytic cell

Different electrodes (anode and cathode) can be used

Different electrolytes can also be used in the anodic and cathodic compartments

SUMMARY

61

ELECTROCHEMICAL DEGRADATION OF AQUEOUS PHENOL AND REMOVAL OF ARSENIC FROM WATER

CHAPTER - 6

Anode : Carbon Cathode : PtAnolyte : 40 ml of phenol Catholyte : 40 ml of 1 N H2SO4

(200 ppm in 0.1 N NaCl) Potential : 5 V

Variation of anode potential and cell current as a function of electrolysis time

( in NaCl medium)

Decomposition profile of phenol in the NaCl medium

ELECROCHEMICAL REMOVAL OF PHENOL

63

Anode : Carbon Cathode : Pt

Anolyte : 40 ml of 200 ppm phenol Catholyte : 40 ml of 1 N H2SO4

Potential : 5 V

DECOMPOSITION PROFILE OF PHENOL IN NaOH AND NaOH + NaCl MEDIUM

Variation of current with time

64M. Sathish and R. P. Viswanath. Korean. J. Chem. Engg. 22 (2005) 358

DECOMPOSITION OF PHENOL IN DIFFERENT MEDIA

.

The decomposition may occur via

Direct oxidation of phenol on the electrode surface

Oxidation by hypochlorite or hypochlorous acid

Chlorination followed by oxidation

The rate of decomposition of phenol and 4-chloro phenol are comparable

In alkaline condition, the decomposition rate of phenol is less compared to neutral medium

65

S.No Compounds max(nm)

1.2.3.4.5.

6.

PhenolPhenoxide iono-Chlorophenolp-ChlorophenolSample (NaCl medium) (after 5 h)Sample (NaCl medium) (after 15 h)

268286272276276

274

max shifts from 268 nm to 276 nm during electrolysis

Chlorination followed by oxidation is one of the pathways of the decomposition

Formation of 4-chlorophenol intermediate has been identified by Gas chromatography & IR spectroscopy

UV-VISIBLE STUDIES

66

OH

Cl

OH

OH

OH

OH

OH

O

O

O

O

+

O

O-

O*

Polymerization

Aliphatic acid

CO2 + H2O

OH

OH

Cl

III PhO-

I II

PROPOSED PATHWAY FOR THE DECOMPOSITION OF PHENOL

In Alkaline medium

Only route II and III are favoured

In neutral medium

Chlorination followed by decomposition will occur – in presence of NaCl

67M. Sathish and R. P. Viswanath. Korean. J. Chem. Engg. 22 (2005) 358

S.NoTime (h)

Phenol concentration

(ppm)

PhenolCOD (ppm)

4-chlorophenolconcentration

(ppm)

4-chlorophenolCOD(ppm)

1.2.3.4.

0203040

191 26 20 12

399134125 93

1992917-

34114713280

PHENOL’S CONCENTRATION AND COD AS A FUNCTION OF ELECTROLYSIS TIME IN NaCl AS SUPPORTING ELECTROLYTE

The change in concentration of phenols shows complete decomposition of phenol from water

The COD values indicate that – No complete oxidation of phenol into carbon dioxide and water

68

Amount of hydrogen produced in the cathode during the

electrolysis in NaCl medium

The chemical reaction for the phenol mineralization is

C6H6O + 7 O2 → 6 CO2 + 3 H2O

Equivalent to 14 moles of hydrogen at the cathode.

The amount of hydrogen generated indicates a current efficiency > 97 %.

Lower amount of decomposition than the calculated value indicates that not all the liberated oxygen is used for phenol oxidation.

CURRENT EFFICIENCY

M. Sathish and R. P. Viswanath. Korean. J. Chem. Engg. 22 (2005) 35869

ACE = 63 % for phenol and 85 % for 4- chlorophenol in the NaCl medium.

The experiments have been carried out in galvanostatic condition (20 mA and 30 mA current )

The standard proposed by WHO is 10 g/L for drinking water

Current

(mA)

Initial concentration

g/L

Final concentration

g/L

20 1082

200

210

13

30 1082

200

156

6

The concentration of arsenic decreased drastically up to 12 h. Concentration profile of arsenic in

galvanostatic condition – 30mA

ELECTROLYTIC REMOVAL OF ARSENIC FROM WATER

70

Electrochemical degradation of phenol is faster in NaCl as supporting electrolyte.

Formation of 4-chlorophenol intermediate enhances the decomposition rate of phenol in NaCl medium.

IR studies show that in the alkaline medium a strong coating of phenolic compounds (polymer) on the electrode surface.

Passive coating may be responsible for the slower degradation in the alkaline medium.

Compartmentalized electrolytic cell - efficient for arsenic removal from water.

SUMMARY

71

CONCLUSIONS

Photocatalytic activity of CdS for hydrogen generation depends on particle size, surface area, crystalline phase and morphology of the system

Photocatalytic activity of TiO2 can be achieved in visible region by substitution of hetero atom (N and/or S) in TiO2 lattice

Hydrogen and Oxygen can be generated at lower applied voltages using compartmentalized electrolytic cell

Water decontamination can also be achieved by employing compartmentalized electrolytic cell

72

Prof. R. P.Viswanath

Prof. B. Viswanathan

Prof. G. Sundararajan

Prof. R. Dhamodharan Dr. G. Ranga RaoProf. A. Ramesh (ME)Prof. T. Panda (CE)

Prof. T.K.Varadarajan, Prof. M.S.Subramanian and Prof. N.Balasubramanian

Dr. C.S.Gopinath – NCL pune

CGBS, SAIF – IIT Madras

Department of Metallurgical and Materials Engineering

UGC and DST

All My Friends

ACKNOWLEDGEMENT

PHOTOCATALYTIC AND ELECTROCHEMICAL PROCESSES FOR GENERATION OF HYDROGEN AND DECONTAMINATION OF WATER M. Sathish CYD01014 20-7-06.

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