PHOTOCATALYTIC AND ELECTROCHEMICAL PROCESSES FOR GENERATION OF HYDROGEN AND DECONTAMINATION OF WATER...
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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
10M. Sathish, B. Viswanathan, R. P. Viswanath Int. J. Hydrogen Energy, 31 (2006) 891
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
12M. Sathish, B. Viswanathan, R. P. Viswanath Int. J. Hydrogen Energy, 31 (2006) 891
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.
15M. Sathish, B. Viswanathan, R. P. Viswanath Int. J. Hydrogen Energy, 31 (2006) 891
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
31M. Sathish, B. Viswanathan and R. P. Viswanath. Int. J. Nanoscience, 6 (2007) 137
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
32M. Sathish, B. Viswanathan and R. P. Viswanath. Int. J. Nanoscience, 6 (2007) 137
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