1 CUBIC MESOPOROUS MCM-48 MATERIALS AS VERSATILE SUPPORT MATERIALS FOR CATALYTIC REACTIONS National Center for Catalysis Research, IIT Madras, Chennai,

1

CUBIC MESOPOROUS MCM-48 MATERIALS AS VERSATILE SUPPORT MATERIALS FOR

CATALYTIC REACTIONS

 National Center for Catalysis Research, IIT Madras, Chennai, IndiaMay 14, 2011

Ranjit T. Koodali

http://www.usd.edu/~rkoodali or http://people.usd.edu/~rkoodali/http://www.vimeo.com/22221632?ab

2

Quick Facts about University of South Dakota (USD)

Location: Vermillion, South Dakota USD is located on an attractive 286-acre campus in Vermillion, a community nestled along

the bluffs above the Missouri River in the southeast corner of South DakotaFounded: 1862 (the State's oldest university)

Enrollment (Fall 2010): Total Enrollment:  10,151 Undergraduate: 7,220 and Graduate: 2,931

Majors: Undergraduate: 132 programs and Graduate: 62 programsFaculty: Total Faculty: 419 and Student-Faculty Ratio: 17:1

Our Mission The University of South Dakota is the comprehensive liberal arts university offering

undergraduate, graduate and professional programs within the South Dakota System of Higher Education.

Our VisionTo be the best small, public flagship university in the nation built upon a liberal arts

foundation.

3

Chemistry at USD

Northern Plains Undergraduate Research Center (NPURC)

NPURC provides opportunities for both beginning and advanced chemistry students. Freshmen students immediately start research in their general chemistry laboratory courses, pursuing projects in water quality, nanoscience, ionic liquids, organic synthesis or related projects.

Participating MembersSD: Augustana College (Sioux Falls, SD), Mount Marty College (Yankton, SD), Sinte Gleska University (Mission, SD), and The University of South Dakota (Vermillion, SD) IA: Briar Cliff University (Sioux City, IA) , Buena Vista University (Storm Lake, IA), and Dordt College (Sioux Center, IA) ND: Fort Berthold Community College (New Town, ND) NE: Nebraska Indian Community College (Macy, NE)Goals:•Implement multi-institutional curricular reform to bring research experiences to a large number of first and second-year students. •Increase research productivity of NPURC participants

http://www.usd.edu/arts-and-sciences/chemistry/northern-plains-undergraduate-research-center/index.cfm

4

Current Projects

Nanostructured (periodic and aperiodic) mesoporous oxides for:

- Photocatalytic splitting of water into hydrogen and oxygen

- Photovoltaic applications – Dye Sensitized Solar Cells (DSSC)Mesoporous materials as chemo-selective oxidation and reduction catalysts

- Synthesis of key intermediate chemicals.Nanostructured oxides as Advanced Oxidation Photocatalysts (AOP)

- Using sunlight to degrade toxic pollutants, improve water quality, clean oil spills etc.(Photo)catalysts for destruction of pathogenic microorganisms

- Using ambient light (or sunlight) to destroy harmful bacteria, and decontaminate Biological and Chemical Warfare Agents (CWA).

5

Y. Wan and D. Zhao, Chem. Rev. 2007, 107, 2821-2860.

Mechanism of formation of periodic mesoporous materials

6

(A) p6mm, (B) Ia3d, (C) Pm3n, (D) Im3m, (E) Fd3m, (F) Fm3m.

Y. Wan and D. Zhao, Chem. Rev. 2007, 107, 2821-2860.

7

Intense research is being conducted in the area of catalysis with attention focused on developing new synthetic protocols and materials, .

Among the class of materials that have captured the imagination of scientists are periodic mesoporous materials.

These materials are characterized by relatively large specific surface areas, uniform pore sizes (that can be varied from 2 nm to as large as 50 nm) and large pore volumes (0.5 – 3.0 cm3/g).

These properties make them attractive for applications that include adsorption, catalysis, drug delivery, sensor applications, and solar energy conversion.

Among the various classes of mesoporous materials, the cubic phase, MCM-48 is thought to be an interesting material for catalytic applications.

This presentation reports efforts in the direction to utilize MCM-48 as a support to facilitate the high dispersion of active species for catalysis reactions.

Periodic Mesoporous Materials

http://personal.teknik.uu.se/teknikvetenskaper/nfm/staff/alfonso/alf-research.html

8

MCM-48 has an interpenetrating network of three dimensional pores and hence is thought to possess favorable mass transfer kinetics compared to the uni-dimensional pores that occur in MCM-41 type of materials.

The reliable and facile synthesis of high quality mesoporous materials, particularly the cubic phase has been a challenge.

The synthesis of MCM-48 is dependent on a number of factors such as temperature, time, stirring rate, reactant ratios, type and chain length of surfactant employed, nature of solvent, and Si precursor.

We have successfully reported the synthesis of MCM-48 in as little as 30 min. at room temperature.

This synthesis is based on the modification of the Stöber synthesis to make uniform silica particles.

Cubic MCM-48 Mesoporous Materials

Boote, B., Subramanian, H., Ranjit, K.T.: Rapid and facile synthesis of siliceous MCM-48 mesoporous materials. Chem Commun. 4543–4545 (2007).

9

MCM-41 MCM-482-D, Hexagonal, p6mm 3-D, Cubic, Ia3d

Interwoven and continuous 3-D pore system

Uni-dimensional pore system

2-D versus 3-D

10

• Reproducible synthesis of Si-MCM-48 in a short time was a challenge until 2007.

• Several synthetic recipe reported previously, but they are tedious, often not reproducible, and also result in low quality cubic phase material.

• In 1999, Schumacher et al. reported a synthetic procedure for the preparation of Si-and transition metal ion containing MCM-48 in 5 – 24 h.

• We have fine tuned this recipe and have been successful in preparing Si-MCM-48 in a very short period of time (30 min.) under ambient conditions.

Synthesis Precursors Temperature/Time

TEOS/C16mimCl/NaOH Hydrothermal (100oC) / 3 days

TEOS/GEM/NaOH Hydrothermal (100oC) / 5 days

TEOS/CTAB/NaOH Hydrothermal (90oC) / 4 days

Na2SiO3/CTAB/NaOH Hydrothermal (100oC) / 2 days

Rapid and Facile Synthesis of Siliceous MCM-48 Mesoporous MaterialsB. Boote, H. Subramanian, and K.T. Ranjit, Chem. Commun. 2007, 4543-4545.

Synthesis of Si-MCM-48

11

CTAB (1.2 g) Water (50 mL)+

Alcohol + Aq. Ammonia

Homogeneous Solution

Si precursor

Calcination

Mesoporous Siliceous Material

Filtration, Washing, Drying

Gel/Precipitate - Silica

12

2 3 4 5 6

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

MCM-48-1800

MCM-48-900

MCM-48-600

MCM-48-300

MCM-48-ns

Inte

nsity

(a

rbitr

ary

nu

mb

ers)

2

Powder X-ray diffraction pattern of calcined mesoporous materials stirred at different rates for 4 h at r.t. The composition of the gel is 0.41 CTAB: 11 aq. NH3: 1.0 TEOS: 53 Ethanol: 344 H2O.

Powder X-Ray Diffraction of Si-MCM-48

13

Mesoporous Material

Surface Area (m2/g)

Pore volume (cm3/g)

Pore diameter

(Å)

Unit Cell parameter

(Å)

MCM-48-ns 1567 0.98 22.2 89.7

MCM-48-300 1339 0.96 22.2 93.2

MCM-48-300-20 1527 0.96 22.2 92.0

MCM-48-300-50 1532 0.85 22.2 93.5

MCM-48-300-110 1437 0.84 22.3 92.1

Textural Properties of MCM-48 Materials

The FIFA soccer dimensions: 100 m (min.) long by 64 m (min.) to give an area of 6400 m2.The American football field is: 120 yards (110 m) long by 53 1/3 yards (49 m) wide for an area of 5390 m2.

14

0.0 0.2 0.4 0.6 0.8 1.0200

250

300

350

400

450

500

550

600

650

700

0 50 100 150 200 250

0

1

2

3

4

5

6

7

8

dV/(l

ogd)

(cm

3 /g/Å

)

Pore Diameter (Å)

Vo

lum

e (c

m3 /g

)

Relative Pressure (P/P0)

Nitrogen IsothermQuantachrome Nova 2200e

Quantachrome CHEMBET 3000

15

Hydrothermal Stability Studies

2 3 4 5 60

1000

2000

3000

4000

5000

6000

7000

8000

MCM48-300-20-HTS-6h

Inte

nsi

ty

2 3 4 5 6

0

2000

4000

6000

8000

10000

3 4 5 6

500

1000

1500

2000

2500

321 40

0

MCM-48-300-20

420 33

2

220

MCM-48-300-20

MCM-48-300-50

MCM-48-300-110

2

Inte

nsi

ty (

arb

itra

ry n

um

be

rs)

Powder X-ray diffraction pattern of calcined mesoporous materials before hydrothermal treatment (left) and after hydrothermal treatment for 6 h (right).

16

• A rapid and facile synthesis of cubic siliceous MCM-48 mesoporous material in as little time as 30 minutes at room temperature was developed.

• The siliceous mesoporous materials have high surface areas (1300-1600 m2 g–1), large pore volumes (>0.8 cm3 g–1) and very uniform pore sizes.

• These materials exhibited modest stability under hydrothermal conditions.

• However, the pore sizes could not be tuned by changing the surfactant chain length.

17

Powder X-ray diffraction patterns of mesoporous MCM-48 materials prepared using various ratios of dodecane/CTAB. The inset shows the corresponding pore size distributions evaluated from Nitrogen adsorption studies).

Nitrogen Isotherm

18

 Mesoporous Material

Surface area

(m2/g)

Pore volume (cc/g)

Pore diameter

(Å)

d211 spacing

(Å)a0

(Å)

Wall thickness

(Å)

MCM-48 1576 0.87 22.0 35.2 86.2 8.8

MCM-48-C12-alkane-0.5 1356 1.04 26.0 38.2 93.5 11.9

MCM-48-C12-alkane-1 1413 1.17 26.2 38.7 94.8 13.4

MCM-48-C12-alkane-2 1101 1.04 25.9 38.6 94.5 12.0

MCM-48-C12-alkane-5 1077 1.17 30.7 40.7 99.7 14.2

MCM-48-C12-alkane-10 1088 1.21 36.1 45*

110.2 16.2

Textural Properties of MCM-48 Materials

19

Applications of MCM-48 mesoporous materials

20

2 3 4 5 60

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

----- Fe-MCM-48 (Si/Fe = 25)

----- Fe-MCM-48 (Si/Fe = 50)

----- Fe-MCM-48 (Si/Fe = 100)

----- Fe-MCM-48 (Si/Fe = 200)

----- Si-MCM-48

XRD of Si-MCM-48 and Fe-MCM-48

21

Baeyer-Villiger Oxidation of 2-adamantanone

Entry Catalyst Time (h)

Conversion (%)a

Yield (%)a

Turnover rate (h-1)b

1 Si-MCM-48 2 11 9.5 -

2 Fe-MCM-48 2 89 80 1.00 x 102

3 V-MCM-48 2 11 9.5 1.23 x 101

4 Fe-MCM-41 4 96 61 6a Calculated by GC-MS using the internal standard (nonane) b calculated assuming that all Fe/V ions are active sites for BVO reaction. Reaction Conditions: 2-adamantanone (2 mmol), benzaldehyde (6 mmol), nonane (0.2 mL), catalyst (0.1 g), 1,2-dichloroethane (20 mL). The system was purged continuously with O 2

at ~ 50 oC during the course of the reaction.Baeyer-Villiger oxidation of cyclic ketones over iron containing mesoporous MCM-48 silica materials,

H. Subramanian, and Ranjit T. Koodali, React. Kinet. Catal. Lett. 95, 239-245, 2008.

1 2

22

Cycle # Weight of the catalyst

Conversion (%) Yield (%)

Fresh 100 mg 89 81

1 89 mg 86 832 70 mg 89 81

Recycling studies of Fe-MCM-48

Bayer-Villiger Oxidation of Cyclic Ketones Using Fe Containing MCM-48 Cubic Mesoporous Materials, H. Subramanian, E. G. Nettleton, S.Budhi and Ranjit T. Koodali, Journal of Molecular Catalysis A: Chemical 2010, 330,

66-72. (doi:10.1016/j.molcata.2010.07.003).

23

Catalysis using Pd-MCM-48 under ligand free and aerobic conditions

Hydrogenation reactions

Chemo and regio-selective hydrogenation reactions

Catalyst 1 - Pd-MCM-48 was found to have surface area of ~ 1800 m2/g with a Pd dispersion of ~ 22% and content of 0.6%.

24

Catalyst 1 - Pd-MCM-48 was found to have surface area of ~ 1800 m2/g with a Pd dispersion of ~ 22%, content of 0.6% and crystallite sizes of < 2 and 4-7 nm.Catalyst 2 - Pd-MCM-48 was found to have surface area of ~ 637 m2/g with a Pd dispersion of ~ 22%, content of 0.6%, and average crystallite size of 12 nm.

Pd-MCM-48: A novel recyclable heterogeneous catalyst for chemo- and regioselective hydrogenation of olefins and coupling reactions, S. Banerjee, V. Balasanthiran, R. T. Koodali and G. A. Sereda, Organic and Biomolecular

Chemistry 2010, 8, 4316-4321

25

The local environment of Ti species is an important factor that influences photocatalytic activity and selectivity for reactions such as decomposition of NO and photocatalytic reduction of CO2 with H2O.

It is a challenge to synthesize titanium containing cubic mesoporous materials at room temperature since the hydrolysis and condensation rates of the titanium alkoxide and the silica alkoxide precursor vary vastly.

We were successful in the synthesis of Ti-MCM-48 through very careful control of experimental parameters.

The coordination state of Ti in MCM-48 matrix was successfully controlled by addition of the titanium precursor at different stages during the formation of MCM-48 gel.

Titania Supported MCM-48 Mesoporous Materials

X-ray diffraction patterns of Ti-MCM-48 of Ti-MCM-48 with Si/Ti of 200 synthesized by four different procedures.

26

Titania Supported MCM-48 Mesoporous Materials

Rapid and Facile Synthesis of Ti-MCM-48 Mesoporous Material and the Photocatalytic Performance for Hydrogen Evolution, Dan Zhao, Sridhar Budhi, Adrian Rodriguez, and Ranjit T. Koodali, Int. J. Hydrogen Energy 2010, 35,

5276-5283. (doi:10.1016/j.ijhydene.2010.03.087).

27

Titania Supported MCM-48 Mesoporous Materials

The photocatalytic mechanism of transition metals dispersed on silica supports is different from bulk semiconductors.

The isolated metal oxide chromophores are excited by UV (or visible light) with appropriate energy and form charge-transfer excited state [Mn+-O-]*.

The hydrogen evolution rates show a good correspondence with the absorption intensities of the LMCT between O2- and tetrahedrally coordinated Ti4+ (not shown).

Thus, it is proposed that the amount of tetrahedrally coordinated Ti-oxide species is the most important factor determining the photocatalytic activity of Ti-MCM-48 for hydrogen evolution.

28

WO3-MCM-48 Mesoporous Materials

Material Si/Wa (mol)

Si/Wb (mol)

Surface areac (m2g-1)

Pore Volumed (cm3 g-1)

Pore diametere

(Å)

Unit cell parameterf

(Å)

W-MCM-48-200 200 1220 1230 1.01 19.8 78.9

W-MCM-48-100 100 516 1092 0.92 20.0 80.4W-MCM-48-50 50 177 1131 0.99 24.2 82.0W-MCM-48-25 25 81 970 0.99 24.3 83.8W-MCM-48-10 10 45 925 1.04 24.3 83.1

a molar ratio in the gel. b molar ratio in the product measured by ICP. c Determined by applying Brunauer–Emmett–Teller (BET) equation to a relative pressure (P/P0) range of 0.05–0.35 in the adsorption isotherm. d Calculated from the amount of

N2 adsorbed at the highest relative pressure of 0.99. e Calculated from the Barrett–Joyner–Halenda (BJH) equation using

the desorption isotherm. f Calculated using the formula a = √6d, where d represents the d211 reflection.

Textural properties of WO3-MCM-48 materials

29

WO3-MCM-48 Mesoporous MaterialsTextural properties of WO3-MCM-48 materials

0.0 0.2 0.4 0.6 0.8 1.0

150

200

250

300

350

400

450

500

550

600

650

700

a b c

Vol

ume

(cm

3 g-1)

Relative pressure (P/P0)

10 100 1000

0

1

2

3

4

5

6

7

8

a b c

dV

(lo

gd

) (c

m3 g

-1)

Pore Diameter (Å)

Left: Nitrogen adsorption-desorption isotherms of (a) siliceous MCM-48, (b) W-MCM-48-100, and (c) W-MCM-48-25. Right: Pore size distribution of (a) siliceous MCM-48, (b) W-MCM-48-100, and (c) W-MCM-48-25.

30

WO3-MCM-48 Mesoporous MaterialsUV-Vis Diffuse Reflectance (DR) Spectra of WO3-MCM-48 materials

200 300 400 500 600 700

0.0

0.5

1.0

1.5

2.0

f

e

d

cb

a

A

bso

rba

nce

(a

.u.)

Wavelength (nm)

6 5 4 3 2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

3.7 eV

3.4V

[K*E

]1/2 (

eV1/

2 )

E (eV)

Diffuse reflectance spectra of (a) WO3, (b) W-MCM-48-200, (c) W-MCM-48-100, (d) W-MCM-48-50, (e) W-MCM-48-25,

and (f) W-MCM-48-10. The insert shows the plots of transformed Kubelka-Munk function versus the light energy.

31

WO3-MCM-48 Mesoporous MaterialsESR of WO3-MCM-48 materials

3200 3400 3600 3800 4000 4200 44004.0

4.5

5.0

5.5

g = 1.776

g = 1.845

gII = 1.695

b

a

Inte

nsity

Magnetic Field (G)

ESR spectra of siliceous (a) MCM-48 and (b) W-MCM-48-10. The spectra were recorded at 5 K after illuminating the samples under UV irradiation at 77 K for 30 minutes.

The samples were EPR silent prior to photoirradiation.

A strong signal near g = 2.003 due to the formation of V centers in silica was observed for both siliceous MCM-48 and W-MCM-48-10 after photoirradiation.

W-MCM-48-10 shows another EPR axially asymmetric resonance signal with g‖‖ = 1.695 and g┴ = 1.776. This signal corresponds to W(V) in tungsten-oxo species.

The small signal at g = 1.846 is due to polytungstate impurity in the sample.

In this study, the resonance of photogenerated hole trapped at lattice oxygen was submerged by the strong signals from V-centers .

Synthesis, Structural Characterization and Photocatalytic Performance of Mesoporous W-MCM-48 by Dan Zhao, Adrian Rodriguez, Nada M. Dimitrijevic, Tijana Rajh and Ranjit T. Koodali, Journal of Physical Chemistry C: Surfaces, Interfaces, and Catalysis 2010, 114, 15278-15734. (10.1021/jp105190v).

32

Solar hydrogen production

Photocatalyst H2 evolution

WO3 0 µmol/h/gW

TiO2 13 μmol/h/gTi

WO3-MCM-48 6015 µmol/h/gW

TiO2-MCM-48 1275 µmol/h/gTi

Crystalline WO3 W, Ti-oxide species

-1.0

0

1.0

2.0

3.0

4.0

H+/H2

O2/H2O

WO3

2.7 eV 3.4 eV3.7 eV

VB

CB

TiO2

33

Summary

Siliceous mesoporous materials can be easily synthesized at room temperature using a modified Stöber method. The synthesis method is amenable for incorporation of transition metal ions and metal nanoparticles in the cubic matrix.

Fe, Ti, and W containing cubic mesoporous materials (Fe, Ti- and W-MCM-48) could be successfully synthesized at room temperature.

Powder XRD, TEM, and nitrogen adsorption isotherms demonstrate that the incorporation of transition metal ions and/or Fe, Ti and W-oxide species do not destroy the ordered mesoporous structure of MCM-48.

Raman spectroscopic and powder XRD studies indicate that the Ti and W-MCM-48 materials show good dispersion of the oxide species in the mesoporous silica matrix.

The metal oxide species that are highly dispersed in MCM-48 matrix possess suitable band gap and sufficient reduction potential for the photocatalytic reduction of H2O to generate H2 and are highly active for catalytic reactions (Heck coupling and Baeyer-Villiger oxidation).

34

Undergraduate Students1. Alberts, Blake D. (B.S. - Chemistry – 2010 – Summa Cum Laude, Sanford School of Medicine Alumni Student Scholar, undergraduate research -

summer and fall 2007, currently M.D. at Columbia University, NY).2. Becker, John (B.S.-Chemistry 2011 undergraduate research, summer 2010).3. Bloch, Tyler (B.S. – Chemistry 2014, anticipated).4. Boote, Brett (NSF-REU Summer 2006 student from Northwestern College, Orange City, IA).5. Fleming, Daniel (B.S. - Chemistry – 2010 research - fall 2008, spring 2009, and summer 2009).6. Freeman, Katie L. (Joint student with Prof. Miles D. Koppang, B.S. - Chemistry - 2008 - University Scholar, Summa Cum Laude, 2008 NCAA

Postgraduate Fellow - Women's Soccer, currently M.D. at Carver School of Medicine, University of Iowa). 7. Gillespie, Andrea (B.S. - Chemistry – 2010 – undergraduate research fall 2009 and spring 2010).8. Gonshorowski, Andi (B.S. – Chemistry – 2011 – Cum Laude, undergraduate research summer 2009, spring 2010, and summer 2010)9. Grady, Anne M. (B.S. – Chemistry 2010 – Magna Cum Laude, University Scholar), currently M.D. at Sanford School of Medicine, The

University of South Dakota).10. Haeder, Paul R. (B.S. – Mathematics - 2007 - University Scholar, Cum Laude, currently M.D. at Sanford School of Medicine, The University of

South Dakota).11. Jacobson, Andrew (B.S. – Chemistry – 2011, undergraduate research spring 2011).12. Leibfarth, Frank A. (B.A. - Chemistry, Physics - 2008 - University Scholar, Summa Cum Laude, 2006 Goldwater Scholar, 2007 All-USA College

Academic First Team, and National Science Foundation - Graduate Research Fellowship Program, and NDSEG-2010, currently Ph.D. at University of California - Santa Barbara).

13. Nettleton, Elizabeth G. (B.S. - Chemistry - 2008, University Scholar, Summa Cum Laude, and 2007 Goldwater Scholar, and NDSEG-2009 currently Ph.D. at University of Texas – Austin).

14. Parker, Nicole M. (B.S. - Chemistry - 2007 - Cum Laude)15. Patrick, Catherine (B.S. – Chemistry 2010 – Magna Cum Laude, University Scholar, currently M.S. – Purdue University, 2010 NASA Aeronautics

Scholarship Program and 2010 National Science Foundation - Graduate Research Fellowship Program).16. Rodriguez, Adrian (B.S. – Chemistry anticipated 2013).17. Rydell, Rachel R. (B.S. - Chemistry - 2006 - Cum Laude currently P.A. – The Sanford School of Medicine at the University of South Dakota).18. St. Pierre, Jordan J. (B.S. - Chemistry - 2010 - University Scholar)19. Turgeon, Anthony (undergraduate research scholarship – spring 2006)20. Turner, Mark D. (B.S. – Chemistry – 2010 - Magna Cum Laude research scholarship – spring 2009)21. Weber, Amanda S. (B.S. - Chemistry - 2009 University Scholar Cum Laude, National Science Foundation - Graduate Research Fellowship

Program , currently Ph.D. at University of California – Irvine).22. Zeleke, Samerawit (B.S. - Chemistry - 2008 undergraduate research scholarship – spring 2008).

35

Graduate and Post-Doctoral StudentsPost-Doctoral Research Associates

Past1.Zhao, Dan - Faculty, Dept. of Chem. Eng. Ningbo Univ. Of Technol.Current1. Parayil, Sreenivasan  GRADUATE STUDENTS Current 1.Thiruppathi, Eagappanath (India, M.S.)2.Kibombo, Harrison (Uganda, Ph.D.)3.Mahoney, Luther (United States of America, Ph.D.)4.Peng, Rui (People Republic of China, Ph.D.)5.Rasalingam, Shivatharsiny (Sri Lanka, Ph.D.) Past 1. Budhi, S. (M.S.-2010) - Ph.D. at Iowa State University2. Balasanthiran, V. (M.S.-2010) - Ph.D. at Ohio State University3. Raghupathi, K. R. (M.S.-2009) - Ph.D. at U. Massachusetts -Amherst4. Sadhu, S. (M.S. - 2008) - Ph.D. at South Dakota State University5. Wu, C.-M. (M.S. - 2008) -    Ph.D. at University of Iowa6. Subramanian, H. (M.S. - 2008) -    Ph.D. at Cornell University7. Psota, R. J. (M.A. - 2007) -    Novatech Inc., Grand Islands, NE

36

Acknowledgments

Department of Chemistry, University of South Dakota (USD).

Office of Research & Sponsored Programs (ORSP), USD – Research Excellence Award, 2010.

University of South Dakota (USD). National Science Foundation (CHE-0532242, CHE-

0552687, CHE-0619190, CHE-0722632, CHE-0840507, DGE-090368, EPS-0554609, and EPS-0903804) and Department of Energy (DE-EE0000270, DE-AC02-06CH11357, and DE-FG02-08ER64624).

State of South Dakota (Center for the Research and Development of Light-Activated Materials, 2004-2009).

37

THANK YOU