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Nickel based bimetallic catalysts supported on titania for selective hydrogenation of
cinnamaldehyde
Presented by M. G. PRAKASH
National Centre for Catalysis Research Indian Institute of Technology, Madras
Introduction Bimetallic catalysts - composed of two metal elements in either alloy or intermetallic form often develop as materials of new category with catalytic properties different from monometallic catalysts.
Generally bimetallic alloys in particular , is an import subject for a number of technological reasons some of which are (1) Catalyst Chemistry (2) Electrochemistry (3) Metal-Metal Interfaces (4) MicroelectronicFabrication etc.
The following aspect of an alloy surface should be examined ,
1)The chemical composition of an alloy surface
2)The surface structure factor
3)The electronic structure and geometric factors
Fig A hypothetical situation of (100) surfaces of an alloy XY with the fcc structure (a) Pure X (b) 50 % X , 50 % Y , ordered (C) 50 % X, 50% Y with Clustering of Y (d)75% X,25 % Y
Nieuwenhuys, The chemical physics of Solid Surface Amsterdam 1993, 6 185-22
Schematic illustration of producing crown jewels structure
X.Liu, D. Wang and Y.Li Nano Today(2012) ,7 448-466
Objectives To prepare Nickel Nano particles by using green chemistry via glucose as reducing agent, supported on P25 .
Preparation of bi-metallic Ni-Cu/TiO2, Ni-Ag/TiO2 and Ni-Au/TiO2 catalysts. Optimization of the reduction conditions for the prepared catalysts.
Studying the Physico-chemical properties of the catalyst samples using various techniques like XRD, TPR, TEM etc.
Studying the catalytic activity of the reduced catalysts using model reactions, liquid phase hydrogenation of cinnamaldehyde.
Identifying the reaction products using GC.
Establishing correlations between the activity, stability and selectivity of the catalysts and their Physico-chemical properties .
6
Reaction scheme Carbonyl group
Olefinic group
Desired productundesired rex
Desired rex
undesired rex
G = 118 KJ/molG = 80.71KJ/mol
G = 37.79 KJ/molG = 0.49KJ/mol
CAL=cinnamaldehyde, COL=cinnamyl alcohol, HCAL= hydrocinnamaldehyde,HCOL=hydrocinnamyl alcohol
Aim and scope of the work
Experimental approach
To prepare, characterize and test performance of following catalysts
1)Influence of preparation Methods (Bimetallic catalysts) • Direct Impregnation Method • Urea Deposition method• Impregnation of stabilzed Ni Nano particles (a)hydrazine hydrate (b) glucose (green chemistry)
0.03 moles of Nickel acetate + 0.03 moles of Cu or Ag or Au + 40 ml of D-glucose solution (0.1 M)
Stirred for 30 min at RT 10ml of liq.ammonia solution
Refluxed for 5 h at 80 C⁰ The solution was changed black colour
1g of TiO2 ( P25) Stirred for 2 h at 80 C⁰
Cooled , centrifuged and dried at 60 C⁰
Preparation of Bimetallic Cataslyst
M .Vaseema,N.Tripathya G. Khangbandb Y.Hahn*aRSC Adv., 2013, 3, 9698–9704
Fig .1 shows the XRD patterns of (a) Ni/P25 (b) Ni-Cu/P25 (c)Ni-Ag/P25 (d)Ni-Au/P25
Fig .2 shows the TPR profile of (a) Ni/P25 (b)Ni-Cu/P25 (c)Ni-Ag/P25 (d)Ni-Au/P25
Fig .3 shows the TEM Images are (a) Ni/P25 (b)Ni-Cu/P25 (c)Ni-Ag/P25 (d)Ni-Au/P25
Fig.4Hydrogenation of cinnamaldehyde on Ni/P25 ,Ni-Cu/P25,Ni-Ag/P25and Ni-Au/P25 conversion and selectivity. Reaction temperature 373 K ,Time 1 h ,catalyst 150 mg, cinnamaldehyde 1.2 g reactant.
Table.1. Hydrogenation of cinnamaldehyde on Ni and Ni based bimetallic catalysts on TiO2 supports at different temperatures
No Catalysts CAL Conv. % Selectivity (%)
HCAL COL HCOL others
1Ni/ P25-100º C Ni/ P25-120º CNi/ P25-140º C
60.091.098.0
63.031.029.0
31.061.027.3
5.06.943.6
1.01.10.1
2
Ni-Cu/P25-60ºCNi-Cu/P25-80ºCNi-Cu/P25-100ºCNi-Cu/P25-120ºC
62.076.389.298.0
14.313.612.511.0
64.546.035.119.0
2038.552.370
1.20.90.11.5
3
Ni-Ag/P25-60ºCNi-Ag/P25-80ºCNi-Ag/P25-100ºCNi-Ag/P25-120ºC
64.076.090.598.0
14.512.710.99.0
60.944.435.918.0
17.540.242.576.0
7.13.70.71.0
4
Ni-Au/P25-60ºCNi-Au/P25-80ºCNi-Au/P25-100ºCNi-Au/P25-120ºC
60.077.092.6598.0
14.113.112.711.0
70.8647.3727.312.2
13.136.349.679.0
1.943.230.40.8
15
Mixture of reactant and products
Reactant
Calibration of GC
COLHCAL
HCOL
C=O bond activation by electropositive Fe on Pt surface
Concept of Lewis sites
Ref: Richard, J. Ockelford, A. Giroir-Fendler, and P. Gallezot, Catal.Lett., 3,53 (1989).
Conculsion
oNi-Au/P25,Ni-Cu/P25 & Ni-Ag/P25 bimetallic systems are showing more activity and selectivity, but when compared to monometallic Ni/P25.
oThe strong interaction between Ni and Cu or Ag or Au was demonstrated to the main reason for the enhanced catalytic activity of catalysts.
oThe Electronic structure of the surface Ni atoms was modified upon the addition of Cu or Ag or Au ,so reducibility of nickel increased.
oImproved the activity can be also ascribed to the high dispersion of Cu or Ag or Au on nickel nanoparticles of the bimetallic catalysts.
Summary
HYDRGENOLYSIS OF BIO-MASS DERIVED POLYOLS TO VALUE
ADDED CHEMICALS
R.Vijaya Shanthi,S.SivasankerNational Centre for Catalysis Research,
I I T – M, Chennai.
One of the most attractive routes of biomass utilization is its direct conversion to valuable organic compounds which gets more and more attention an ever .
An effective process for the biomass utilization is hydrogenolysis of polyalcohols derived from biomass.
Hydrogenolysis has a great potential in the conversion of biomass-derived polyols, such as sugars or sugar alcohols.
Introduction
We had earlier reported studies on Ni, Pt and Ru supported on the basic support, NaY for sorbitol hydrogenolysis. (Topics in Catalysis (2012) 55:897–907.)
As a part of our investigations on the influence of the support on the performance of supported metal catalysts we have now carried out hydrogenolysis of glucose & glycerol over unconventional support, viz.
Present work
Hydroxyapatite
Materials based on Ca10(PO4)6(OH)2 (hydroxyapatite, HAP) have attracted tremendous interest because of high stability at high temperatures and least soluble in aqueous medium which will be very useful for reactions involving aqueous medium .
Taking into account environmental and economical considerations, the handling of hydroxyapatite used as a catalyst presents many advantages such as to easier separation,recovery from the reaction mixture and thus, enhanced recycling possibilities, which are now well established in fine organic synthesis.
HAP has recently received much attention in view of its potential usefulness as adsorbent and most importantly as catalyst in solid/gas reactions.
The various products obtainable by hydrogenolysis of glucose
Crystalline structure of hydroxyapatite
stirred at room temperature
Filtered, dried for 12 h at 120 °C
Calcined in air at 600 °C for 4 h
Reduced in H2 for 4 h at 400 °C (prior to use)
6%Ni/HAP;1%Pt/HAP;1%Ru/HAP
refluxed for 4 h
7.927g of (NH4)2HPO4 in 250ml solution( at a pH>12 (60–70 ml NH4OH) )+ 23.63 g of Ca(NO3)2 .4H2O
in 150ml solution
Impregnation method-(Ni -6 wt.%;Pt-1 wt.%;Ru-1 wt.%)
HAP
dried for 12 h at 120 °C
Calcined in air at 600 °C for 4 h
Synthesis of HAP & preparation of catalysts
Support
Catalyst
Characterization of HAP & the catalysts
XRD patterns Physicochemical property
TEM images - The crystals are rod-like in shape & the particles are ofapproximately 20–40 nm in diameter with 40–60 nm in length.
Catalyst SBET
(m2/g)
Pvtot
(cm3/g)
Av. pore
dia.(Å)
Metal dispersion (%) [crystallite
size, nm]
HAP (Ca:P-1.58) 45 0.42 374
Ru(1%)-HAP - - - 26 [2.2]
Pt(1%)-HAP - - - 15 [11.4]
Ni(6%)-HAP - - - 2.5 10.4]
6%Ni- H
AP
12%Ni- H
AP
6%Cu- HAP
12%Cu- HAP
1%Pt- H
AP
1%Ru- HAP
0
10
20
30
40
50
60
70
80
90
100 CONV. SEL. (PD+EG)
Wt
(%)
180 190 200 210 2200
10
20
30
40
50
60
70
80
90
100
Temperature C
Con
vers
ion
/sel
ecti
vity
(W
t%)
Conversion 1,2-PD EG
Conditions: 15% glycerol in water; press.: 60 bar; time: 6 h; stirring speed: 300rpm; G= glycerol; PD = 1,2-propanediol & EG = ethylene glycol; A-absence of base; B-presence of base
Effect of temperature – 12%Ni/HAPEffect of catalysts
Fresh I Cycle II Cycle III Cycle0
10
20
30
40
50
60
70
80
90
100
Con
vers
ion
/sel
ecti
vity
(W
t%)
CONV. SEL. (PD+EG)A
Fresh I Cycle II Cycle III Cycle0
10
20
30
40
50
60
70
80
90
100
B
Con
vers
ion
/sel
ecti
vity
(W
t%)
CONV. SEL. (PD+EG)
A
Recyclability – 12%Ni/HAP
0
10
20
30
40
50
60
70
80
90
100
0
10
20
30
40
50
60
70
80
90
100
CONV. SEL. (PD+EG)
Wt
(%)
A
0
10
20
30
40
50
60
70
80
90
100
B CONV. SEL. (PD+EG)
Wt
(%)
Effect of solvent– 12%Ni/HAP
The presence of base enhances the conversion & selectivity
Catalyst Glucose Conv.
(%)
Product Selectivity (wt%)
S Dihydric alcohols
G Others
1,2 PD EG
Ru/Hap 80 26 20 18 16
Ru/Hap+ Ca(OH)2 86 22 22 20 14
Pt(1%)-HAP 74 34 18 20 12
Pt/Hap+ Ca(OH)2 80 31 21 20 14
Ni/Hap 96 18 18 24 26
Ni/Hap+ Ca(OH)2 98 10 16 26 28Conditions: 15% glucose in water; cat.: 0.2 g; temp.: 140 °C; press.: 60 bar; time: 6 h; stirring
speed: 1000 rpm; S = Sorbitol; G= glycerol; PD = 1,2-propanediol & EG = ethylene glycol; trihydric(except glycerol) and higher alcohols; monohydric alcohols and :others
(methanol,ethanol&butanol); Ca(OH)2 , 0.25g.
Order of activity: (A) Ni/Hap > Ru/Hap > Pt/Hap (in absence of Ca(OH2). (B) Ni/Hap > Ru/Hap > Pt/Hap (in presence of Ca(OH2).
Effect of reaction parameters – 6%Ni/HAP
120 130 140 150 1600
10
20
30
40
50
60
70
80
90
100
Temperature C
Con
vers
ion/
sele
ctiv
ity
(Wt%
)
Conversion Glycerol 1,2-PD EG
Temperature
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.450
10
20
30
40
50
60
70
80
90
100
Conversion Glycerol 1,2-PD EG HA
Catalyst amount (g)
Con
vers
ion
/sel
ecti
vity
(W
t%)
Catalyst amount
Effect of run duration – 6%Ni/HAP
0
10
20
30
40
50
60
70
80
90
100
6%Ni- H
AP
1%Pt- H
AP
1%Ru- HAP
0
10
20
30
40
50
60
70
80
90
100 CONV. SEL. (PD+EG)
Wt
(%)
Yield (PD+EG)
Temp - 140 °C; Catalyst - 0.2g Run duration – 6 h
Optimum conditions
Effect of catalysts
0 1 2 3 4 5 6 7 8 9 10 11 120
10
20
30
40
50
60
70
80
90
100
Conversion Glycerol 1,2-PD EG
Con
vers
ion
/sel
ecti
vity
(W
t%)
Time (h)
B
0 1 2 3 4 5 6 7 8 9 10 11 12 130
10
20
30
40
50
60
70
80
90
100
Conversion Glycerol 1,2-PD EG
Con
vers
ion
/sel
ecti
vity
(W
t%)
Time (h)
A
Recyclability – 6%Ni/HAP
Fresh I Cycle II Cycle III Cycle0
10
20
30
40
50
60
70
80
90
100
C
on
ver
sio
n/s
elec
tivit
y (
Wt%
)
Conversion Glycerol 1,2-PD+EG
A
Fresh I Cycle II Cycle III Cycle0
10
20
30
40
50
60
70
80
90
100
C
on
ver
sion
/sel
ecti
vit
y (
Wt%
)
Conversion Glycerol 1,2-PD+EG
B
(A) in the absence of Ca (OH)2and (B) in the presence of Ca(OH)2
Conditions: Temp., 140 °C; pressure, 60 bars; run duration, 6 h; catalyst, 0.2g; sorbitol, 15 g; water, 85 g; Ca(OH)2 , 0.25g.
The presence of base enhances the conversion & selectivity marginally
The influences of temperature, catalyst loading and reusability on sorbitol conversion and selectivity were investigated with 6%Ni/HAP catalyst. The influence of the addition of the base Ca(OH)2 on conversion and product yields is also influenced the conversion and selectivity of both glycerol & glucose.
The influence of the support on Hydrogenolysis of glycerol & glucose was investigated over HAP metal supported catalysts.
The loading of the metals was: Ni, 6%; Cu, 6 %; Ru 1 %; and Pt, 1 %. Ni/HAP & Ni/Hap were found to be the most active and selective (for glycols) amongst all the catalysts.
Conclusion
Mechanism of the hydrogenolysis of sorbitol in the presence of a base
A general observation is that the reaction proceeds better in a basic medium, typically, in the presence of Ca(OH)2.
Photocatalytic reduction of Carbon dioxidePhotocatalytic reduction of Carbon dioxide over Strontium titanate surfacesover Strontium titanate surfaces
V. Jeyalakshmi, K. R. Krishnamurthy & B. ViswanathanNCCR, IIT Madras
Utilization of COUtilization of CO2 2 - A global endeavor- A global endeavor
Global demand for energy to set to increase by 50 % by 2030
Fossil fuels continue to be the major source of energy
Increase in CO2 emission levels- a matter of concern
Increase in earth’s average surface temp. - 0.6K in the last century
Green house effect, changes in weather patterns
COCO22 management - A challenging task management - A challenging task
Utilization of COUtilization of CO2 2 - A global endeavor- A global endeavor
Processes for COProcesses for CO22 conversion conversion
Chemical
Photo-chemical
Bio-chemical
Photo bio-chemical
Radio-chemical
Electro-chemical
Photo electro-chemical
Photo bio-electrochemical (MA Scibioh & B.ViswanathanProc.Ind.Natl. Sci.Acad.70A,407,2004)
.
Photo catalytic reduction that utilizes solar energy which has
tremendous potential
Photo catalytic reduction of COPhoto catalytic reduction of CO22 with H with H22OO
Process & catalyst Splitting of water to yield hydrogen Reductive conversion of CO2 to hydrocarbonsBoth steps proceeding via photo catalysis. Bi-functional catalyst design to include components that are
active for both functionalities suitable for activation with the most abundant visible light
Challenges for practical applicationChallenges for practical applicationMaximization of hydrocarbons formation Maximization of hydrocarbons formation Selectivity towards narrow range hydrocarbons
Choice of catalysts- Guiding principlesChoice of catalysts- Guiding principles
Valence band top energy level to be suitable for splitting of water Conduction band bottom energy level to be more negative with
respect to reduction potential of CO2
VB & CB potentials for selected semi-conductors relative to the energy levels for CO2 redox couples in water(T.Inoue, A.Fujishima,S.Konishi & K.Honda, Nature,277,637,1979)
38
SrTiO3, Sr3Ti2O7 & Sr4Ti3O10
Kudo et al. Chem. Soc. Rev., 38(2009) 253
SrTiO3, as one of the most promising photocatalysts, is now used in various practical applications.
In these materials , slabs of SrTiO3 are cut parallel to
the idealised cubic perovskite (100) planes and stacked
together , each slab being slightly displaced from the process.
COCO2 2 Photo reduction on Strontium titanate surfacePhoto reduction on Strontium titanate surface
The large band gap sizes of early transition-metal oxides (>3.0eV) restrict The large band gap sizes of early transition-metal oxides (>3.0eV) restrict their photocatalytic activities to ultraviolet wavelengths.their photocatalytic activities to ultraviolet wavelengths.
Non metal doping (N doping) Metal doping (Fe doping) (a) the charge carrier recombination time is largely influenced by the presence of iron cations, (b) presence of iron induces a batho-chromic effect, and (c) iron doped photocatalyst is efficient in several important photocatalytic reduction and oxidation reaction
STO:N, Fe. Will exhibit high photocatalytic activities under vis illumination, which is due to the decrease in the oxygen vacancies
because co doping maintains the charge balance.
Modified Strontium titanate catalystsModified Strontium titanate catalysts
Synthesis of SrTiO3 Polymerized complex method gives fine and well-crystalline powders with
a high surface area at relatively low calcination temperature and short
calcination time compared with a conventional solid state method.
Kudo et al. Chem. Soc. Rev., 38(2009) 253–278
Ethylene glycol : Methanol(1:2).
0.5mole of Citric acid + 3mole of Sr(NO3)2 + 2mole of Urea/Thiourea or 3% Fe2O3 added to the mixture .
The solution was stirred at 130°C for 20 hrs.
The resulting polymerized complex gel was pyrolyzed at 350 °C
N,S/Sr3Ti2O7 or Fe2O3/Sr3Ti2O7
2 mole of C16H36O4Ti was added.
Precursor was calcined at 900°C for 2 h.
Methanol, Ethylene glycol , citric acid should be in the molar ratio of 1:2:0.5.
H.Jeong et al. International Journal of Hydrogen Energy 31 (2006)1142 – 1146
Preparation of Strontium titanate
XRD pattern for SrTiOXRD pattern for SrTiO33
The shift indicates that a part of Iron at least is homogeneously doped into the SrTiO3 lattice. Ionic radii of six-coordinated Fe3+ (0.62A˚) are almost the same
as Ti4+ ion (0.61A˚).
XRD pattern for SrXRD pattern for Sr33TiTi22OO77
The shift indicates that a part of Iron at least is homogeneously doped into the Sr3Ti2O7 lattice. Ionic radii of six-coordinated Fe3+ (0.62A˚) are almost the same
as Ti4+ ion (0.61A˚).
XRD pattern for SrXRD pattern for Sr44TiTi33OO1010
The shift indicates that a part of Iron at least is homogeneously doped into the Sr4Ti3O10 lattice. Ionic radii of six-coordinated Fe3+ (0.62A˚) are almost the same
as Ti4+ ion (0.61A˚).
Catalyst Crystalline size (nm)
Band gap (nm)
SrTiO3 28.9 3.05
Fe/NS/SrTiO3 33 3
Sr3Ti2O7 46 3.14
Fe/NS/Sr3Ti2O7 39 2.4
Sr4Ti3O10 52.7 3.12
Fe/NS/Sr4Ti3O10 46.7 2.9
DR spectra for the catalystsDR spectra for the catalysts
Photo luminescence spectraPhoto luminescence spectra of the catalystsof the catalysts
Co doping increases exciton life time.
SEM ImageSEM Image
SrTiO3 Sr3Ti2O7 Sr4Ti3O10
Fe NS SrTiO3 Fe NS Sr3Ti2O7Fe NS Sr4Ti3O10
Reactor volume - 650 mlReaction medium - 400 ml of 0.2 N aqueous NaOH.Temperature- 298KCatalyst loaded - 0.4g. Dispersed in the medium with continuous agitation-400 rpmCO2 was bubbled for 30 min.
pH of the medium- Reduced to 8.0 after saturation with CO2 from the initial value 13.0 Reaction medium was irradiated through a 5cm dia. quartz window.Light source-High pressure Hg lamp-UV-Vis radiation -300-700 nm
77W powerThe products were analyzed using Perkin Elmer Clarus 500 Gas chromatograph - Poroplot Q, 30 m, at 150ºC with FID for analysis of hydrocarbons and Mol.Sieve 5A column for H2 & O2 analysisGas (0.2 ml) and liquid (1 µl) phase samples were withdrawn every two hours from the reactor and injected into the GC.
Reaction & AnalysisReaction & Analysis
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
• Reactor volume - 650 ml, Reaction medium - 400 ml of 0.2 N NaOH .• Catalyst loaded - 0.4g . CO2 was bubbled for 30 min.
Catalyst Products formed after 20hrs of irradiation (μmol/g) Conversion (%)CH4 C2H4 C2H6 CH3OH C2H4
OC2H5
OHC3H6
OC3H6 Total CO2
consumed
SrTiO3 0.42 0.3 0.14 212 0 89.2 0 0 391.8 0.55
Fe/NS/SrTiO3 0.5 0.6 0 498.9 0 66.4 0 0.2 567.8 0.79
Sr3Ti2O7 0.5 0.2 0.2 248.8 7.6 53.4 0 0.2 373 0.5
Fe/N,S/Sr3Ti2O7 0.1 5.4 0.2 561 1.6 284 25 0.9 1221.7 1.7
Sr4Ti3O10 0.22 0.8 0.2 222.3 0 129. 0 0.8 485.4 0.68
Fe/NS/Sr4Ti3O10 0.28 0 0.2 409.6 1.8 123.6 0 0 661.1 0.93
Photo reduction of COPhoto reduction of CO22- Cumulative - Cumulative
conversionconversion
Activity pattern for COActivity pattern for CO22 photo photo reductionreduction
SrTiO3, Sr3Ti2O7 ,Sr4Ti3O10 & modified samples were prepared by polymerised complex method.
Layered strutured shows impured photocatalytic activity compared to neat perovskite SrTiO3, which is probably due to separation of active site and increased the exciton life time.
SrTiO3 codoped with nitrogen and Iron exhibited the high photocatalytic activity due to the decrease of the oxygen vacancies, which may act as electron-hole pair recombination centers, because codoping with Fe3+ and N3- ions maintained the charge balance.
SummarySummary
Thank you!Thank you!
pH dependent carbonate ions in solution
After bubbling carbon dioxide the most likely species present in the reaction medium is HCO3
-
OH- ions act as hole scavengers, form OH radicals, and reduce the electron-hole recombination rate. Increase in lifetime of photo electrons would facilitate the reduction of CO2.(I-H
Tseng et al.,Appl.Catal.B Env.37,37,2002)
Alkaline medium increases the solubility of CO2.
Role of alkaline (NaOH) reaction Role of alkaline (NaOH) reaction mediummedium
Criteria for selection of SC photo-catalysts1. The SC should have narrow band gap to absorb as much light as possible.2. The bottom of the conduction band must be more negative than the
reduction potential of water to produce hydrogen and the top of the valence band must be more positive than the oxidation potential of water to evolve oxygen.
3. Efficient charge separation and fast charge transport simultaneously avoiding the bulk and surface recombination are essential to migrate the photo-generated charge carriers to the surface reaction sites.
4. Kinetically feasible surface chemical reactions must take place between the charge carriers and water or other molecules and the backward chemical reaction should be capable being suppressed.
Outcome Develop SC specific bulk and surface propeties and energy band structures to satisfy these demands
Xinchen Wang, Kazuhiko Maeda, Arne Thomas, Kazuhiro Takanabe, Gang Xin, Johan M. Carlsson, Kazunari Domen & Markus Antoniett : A metal-free polymeric photocatalyst for hydrogen production from water under visible light, Nature Materials 8, 76 - 80 (2009)
a, Schematic diagram of a perfect graphitic carbon nitride sheet constructed from melem units. b, Experimental XRD pattern of the polymeric carbon nitride, revealing a graphitic structure with an inter planar stacking distance of aromatic units of 0.326 nm. c, Ultraviolet–visible diffuse reflectance spectrum of the polymeric carbon nitride. Inset: Photograph of the photo-catalyst.
a, Density-functional-theory band structure for polymeric melon calculated along the chain (Gamma–X direction) and perpendicular to the chain (Y–Gamma direction). The position of the reduction level for H+ to H2 is indicated by the dashed blue line and the oxidation potential of H2O to O2 is indicated by the red dashed line just above the valence band. b, The Kohn–Sham orbitals for the valence band of polymeric melon. c, The corresponding conduction band. The carbon atoms are grey, nitrogen atoms are blue and the hydrogen atoms are white. The isodensity surfaces are drawn for a charge density of 0.01qe Å-3.
A typical time course of H2 production from water containing 10 vol% triethanolamine as an electron donor under visible light (of wavelength longer than 420 nm) by (i) unmodified g-C3N4 and (ii) 3.0 wt% Pt-deposited g-C3N4 photocatalyst. The reaction was continued for 72 h, with evacuation every 24 h (dashed line). Unmodified g-C3N4 also photocatalysed steady H2 production from aqueous methanol solution (10 vol %)
Steady rate of H2 production from water containing 10 vol% methanol as an electron donor by 0.5 wt% Pt-deposited g-C3N4 photo-catalyst as a function of wavelength of the incident light. Ultraviolet–visible absorption spectrum of the g-C3N4 catalyst is also shown for comparison.
Time courses of O2 production from water containing 0.01 M silver nitrate as an electron acceptor under visible light (of wavelength longer than 420 nm) by 3.0 wt% RuO2-loaded g-C3N4. La2O3 (0.2 g) was used as a buffer (pH 8–9).
Thermal stability 873 K chemical stability acid base and organic solvents, Eg ~ 2.7 eV band positions suitable for water reduction and oxidation. Shining star of photo-catalysis
Synthesis of C3N4
Thermal condensation of nitrogen rich precursors such as cyanamide, dicyandiamide, melamineTexture modification, elemental doping, copolymerization
To: Viswanathan B
Perspectives and outlook1. Amenable for modification
2. Medium band gap with HOMO and LUMO positions for electron transfer with powerful chemical potential
3. Artificial photosynthesis, oxygenation, reduction, base catalysis, aromatic, double and triple bond activation.
4. Metal free, thermal, chemical stability, tunable electronic structure, abundant, cheap
5. Rates are still low role of covalence in reversible bonds formed or split
6. Enzyme like functionality possible
7. Structure and catalytic activity correlation?
8. Increasing the domain size and improvement of electrochemical properties due to incomplete poly condensation
9. Only a few reactions have been addressed - substrate specific reactions will be the future challenge
8
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Academy-Research-Industry.Academy-Research-Industry.
T H E M A N D A T ET H E M A N D A T E
Actively build human capacities and expertise manpower in the area of Catalysis through structured educational programs at various levelsUndertake advanced research in frontier areas of basic sciences relating to Catalysis: ◙ New materials ◙ Energy Conversion
Processes◙ Surface Science ◙ Theoretical Science
Solicit support from industries for applied research in cutting-edge technology areasEmerge as a knowledge center & store house of relevant information to user industries towards reliable problem solving, testing & training Initiate collaborative research programs with universities, national and international institutes and laboratories
NCCRNCCR
NCCNCCRR
Clear focusClear focusSurface scienceSurface scienceNew materialsNew materialsEnergy conversion Energy conversion processesprocessesTheoretical approachesTheoretical approaches
Ordered meso porous materialsReduction of carbon dioxide in combination with
water splitting to yield fuels and chemicalsSplitting of water for hydrogen generationFixing of nitrogen as ammonia. Alternate routes for hydrogen generationNew materials for hydrogen storageDesign and fabrication of alternate noble metal
based electrodes for fuel cell -Synthesis of new materials
Biomass conversion to platform chemicals Surface analysis at atomic and molecular level
by electron spectroscopyTheoretical studies for catalyst development –
employing DFT and other modern theories for condensed matter applications.
Research programmes in frontier areas
NCCR has successfully achieved NCCR has successfully achieved the goal/ mandates the goal/ mandates
Research Scholars Orientation programs-14Research Scholars Orientation programs-14M Tech Degree Course in Catalysis Technology-4M Tech Degree Course in Catalysis Technology-4Ph. D Degree Course- 5/25Ph. D Degree Course- 5/25Advanced research facilities in CatalysisAdvanced research facilities in CatalysisResearch programmes in frontier areasResearch programmes in frontier areasCollaborations with International and National Collaborations with International and National Universities/Institutes Universities/Institutes Establishing vibrant academia-industry Establishing vibrant academia-industry partnership- 12 industry sponsored research partnership- 12 industry sponsored research projectsprojectsCharting out a road map for futureCharting out a road map for future
NCCR-Research Contributions
Publications in journalsPublications in journals 228228
Presentations in Seminars/SymposiaPresentations in Seminars/Symposia 248248
PatentsPatents 18 18
Books/ChaptersBooks/Chapters 29 29
CatalysisCatalysisNearly two centuries old; continues to be an ever-green
branch of science, exciting & vibrantTremendous impact on society & science
Four Nobel prizes in Catalysis in the last decade-Asymmetric catalysis, Olefins MetathesisSurface chemistry, Pd catalyzed Cross-couplings
> 30 journals explicitly devoted to Catalysis besides
ACS & RSC journals New journals started in 2011-ACS- Catalysis ; RSC-Catalysis –Science & Technology
Undergoing a renaissance-science & technologyShift in focus- from chemical processes to Energy & Environment- major concerns of modern society
Set to emerge as a source for sustainable Set to emerge as a source for sustainable solutionssolutions
The approach ……..The approach ……..Basic functionalities to be built in : Activity, Selectivity,
Life, Regenerability, Thermal & Mechanical stabilitySelection of catalytic components that generate the
functionalities for a specific process- Empirical → Rational
Architectural approach in effective integration of the components.
Scientific basis for selection & integration-theoretical & experimental validation - - Significant progress
Concept of active centreConcept of active centre
The basis for catalyst designThe basis for catalyst design
Design of Design of CatalystsCatalysts
Supported metal catalysts-guiding principles Pt metal-Bulk Crystal-Crystal planes- Surface structure--active sites
Bonding/Reactivity of reactants on terrace/step/kink sites is determined by the co-ordination numbers/co-ordinative unsaturation
For cyclic hydrocarbon reactant C-H bond activation – step sites- Dehydrogenated product C-C- bond activation - kink sites- Ring opening
Active phase composition-Structure-Size-ShapeActive phase composition-Structure-Size-ShapeSurface structure-SelectivitySurface structure-Selectivity
Active sites on the Active sites on the surfacesurface
Topics in Catalysis (2010) 53:832–847
The resurgenceAdvent of nano science & technologyRole of size and shape of nano particles
Size-Activity ; Shape –SelectivityRange of catalyst preparation techniques
Colloidal synthesis, self-assembly, use of dendrimersSynthesis & characterization of New materials
Ordered mesoporous materials, MOF, CNT, GraphenesAdvanced theoretical-computational methodsSurface sensitive analytical techniques-molecular/atomic
levelCombinatorial catalysis
High throughput catalyst evaluation & preparation
Rational approach to design of catalystsRational approach to design of catalysts
Novel catalyst architecturesNovel catalyst architectures
Enabling techniques & Enabling techniques & toolstools
Design of active Design of active centrescentres
Well defined morphology Size & Shape control Exposure of specific planes Analytical techniques
AdsorptionActivationSurface reactionsDesorption
Activity Selectivity Stability
Process
Surface reactivity Performance
Mechanistic pathways
Surface structure
Preparation methods
Theoretical studies
Energetics of Reactant-surface
interactions
Modern approachesModern approaches
Sustainable processes and products Sustainable processes and products through Catalysis- Challengesthrough Catalysis- Challenges
Energy-Environment-Renewable feed-stocks-Energy-Environment-Renewable feed-stocks-Design, Synthesis and Application of New materialsDesign, Synthesis and Application of New materials
NCCR- Future activitiesNCCR- Future activities
Emphasis on•Educational activities•Training and manpower development•New areas of research-basic & applied•Strengthen research facilities•Expand research collaborations
NCCR-Plan for Next 5 YearsNCCR-Plan for Next 5 Years
Road aheadTo spread its wings over several emerging and new frontiers in the science of catalysis. To carve out its own place within IIT Madras as a vibrant entity with significant contributions in contemporary topics in Catalysis.
Focus for the next five years Intensifying Academic Research leading to publications in high impact journals.Aggressively pursuing Industry supported or industry oriented projects that would lead to Patent Disclosures covering cutting-edge product development/process technologies. Strengthening Academic activities related to: • Research for imparting knowledge and training to young researchers.• Resource generation in terms books, e-books and databases.
Expanding and strengthening international collaboration with other Catalysis Research Centres across the globe and provide a platform for Indian Scientists a uniform play ground to compete internationally.
To tread along the growth path & strive for recognition at global level
NCCR on Global HorizonNCCR on Global Horizon
Catalysis has emerged as a leading branch of science in the last two decades and expected to grow further Amply reflected with the initiation of specialized journals by RSC, ACS Catalysis will continue to flourish and blossom into a branch of science attracting fundamental knowledge creation and helping to achieve sustainable living in this universe.
Energy-Environment- Life style & EconomyEnergy-Environment- Life style & Economy The economic and environmental benefits of Catalysis have been established beyond doubt and will continue to be the centre stage of knowledge generation in the decades to come. India has in the past evolved path-breaking methodologies for a sustainable society in this world, could take lead and become one of the torch bearers in modern science. NCCR would play a major role in the realization of India’s potential in this branch of science and emerges as the knowledge centre.
NCCR on a Growth Path
NCCR has the potential to emerge as a:
• Knowledge storehouse not only for this country but to the entire world
• International centre for creation of skilled and competent human resources
• Centre where not only research in cutting edge technologies will be developed but also a nucleus for generating newer directions for research and practice in industry.
Above all, a Centre of excellence in an academic and applied area like Catalysis will be directly reflecting in the economy of the country.The Centre will have a leading role and contribute towards the advancement of science & technology in the years to come
On this day, 27th July 2014, let us all re-dedicate ourselves to the task of building a strong and vibrant NCCR
Thank you !
