Reusable NickelReusable Nickel--Based Based

Materials for Small Materials for Small

Scale Ammonia StorageScale Ammonia StoragePatrick J. DesrochersPatrick J. Desrochers

Dept. of Chemistry, University of Central Arkansas, Conway, AR 72035patrickd@uca.edu

AFV, Minneapolis, MN Sep 2008

• Global energy gases—ammonia in context

• Tp*NiX(s) binding of ammonia

• Advantages of the organic anchorage

• Tp*NiBH4: ammine-borane hybrid

yearreproduced from S. Dunn International Journal of Hydrogen Energy 2002, v. 27, p 235.

Gases

LiquidsIncreasinglySustainableEconomic GrowthDecentralized less capital-intensivetechnologies

Non-SustainableEconomic GrowthCentralized capital-intensivetechnologies

Solids

Global transition to energy gases Global transition to energy gases

Ammonia

1850 1900 1950 2000 2050 2100 2150

0

20

40

60

80

100

Oil and naturalgas liquids

Methane

Hydrogen

Wood and hay

Methane

Coaland Nuclear

PetroleumOil

OilandHydro

“City Gas”Hydrogen

Whale oil

perc

enta

ge o

f to

tal m

ark

et

1997

Actual Consumption

H:C 0.5:1coal 2:1oil 4:1NG �:1NH3,H

The Chronicle of Higher Education Oct 10, 2003.

Thepromise of a hydrogeneconomy

Gasoline 48

Methane 56

Lithium 42

Hydrogen 143

Fuel ∆Hocomb,kJ/g

Thechallenge of a hydrogeneconomy

• amides M(NH2)n

• boranes BH3NH3

• ammines M(NH3)nXm

storage

The Chronicle of Higher Education Oct 10, 2003.

Orimo, S.; Nakamori, Y.; Eliseo, J. R.; Z�ttel, A.;Jensen, C. M. Chem. Rev. 2007, 107, 4111.

Amides Amides

• Mixed amide/hydrideimproved desorption T

• Variable compositions provide tunable control

• T(H2) formation < T(NH3)

Mg(NH2)2 + nLiH Mg3N2 + LixNHy + nH2

N O F NeB C

He

P S Cl ArAl Si

AmmineAmmine--boraneborane

ethane(g)

C C

H

HH

H

H

HC C

H

HH

H

H

H

N O F NeB C

He

P S Cl ArAl Si

AmmineAmmine--boraneborane

ammine-borane(s)

B N

H

HH

H

H

HB N

H

HH

H

H

H+

-

+

-

THFNaBH4 + NH4Cl H2 + BH3NH3 + NaCl

Ramachandran, P. V.; Gagare, P. D. Inorg. Chem. 2007, 46, 7810-7817.

Mg(BH4)2(NH3)2(s)

Soloveichik, G.; Her, J. –H.; Stephens, P. W.; Gao, Y.; Rijssenbeek, J.; Andrus, M.; Zhao, J. -C.Inorg. Chem. 2008, 47, 4290-4298.

original report: Konoplev, V. N.; Silina, T. A. Zh. Neorg. Khim. 1985, 30 (5), 1125.

m.p. 94 oC

Mg

NH3

NH3

H

BH H

H

H

BH H

H

AmmineAmmine--boraneborane hybrids hybrids

• N-H…H and B-H…H parameters comparable to BH3NH3(s)• endothermic H2/NH3 release vs BH3NH3(s)

“Metal Derivatives of Ammonia-borane: Potential hydrogen storage materials”

Diyabalanage, H. V. K.; Shrestha, R. L.; Semelsberger, T. A.; Scott, B. L.; Burrell, A. K. 236th ACS Natl. Mtg, Philadelphia, August 2008: FUEL 56.

AmmineAmmine--boraneborane hybrids hybrids

M(NH2BH3)n (M = Ca, Mg, Ti, Sc; n = 1-6)

• variable thermal properties• H2 without foaming• thermal stability improvement • controlled H2 release

Fuel DivisionInorganic Division

Carl Bosch

(shared with Friedrich Bergius)

1931Fritz Haber

1918

HaberHaber--Bosch: Nobel worthy chemistry Bosch: Nobel worthy chemistry

motivated by national security interests

motivated by national security interests

Ammines Ammines

Sørensen, R. Z.; Hummelshøj, J. S.; Klerke, A.; Reves, J. B.; Vegge, T.; Nørskov, J. K.Christensen, C. H. J. Am. Chem. Soc. 2008, 130, 8660–8668.Christensen, C. H.; Sørensen, R. Z.; Johannessen, T. ; Quaade, U. J.; Honkala, K.; Elmøe, T. D.; Køhler, R.; Nørskov, J. K. J. Mater. Chem., 2005, 15, 4106 – 4108.

Ca(NH3)8Cl2 9.8 0.116Mn(NH3)6Cl2 8.0 0.112Mg(NH3)6Cl2 9.2 0.115Ni(NH3)6Cl2 7.8 0.119

mass% H kg H/L

M

H3N

H3N NH3

NH3

H3N

NH3

X

X

incre

asin

g T

des

• ρpellet 95 – 99% of crystalline• nanopores facilitate NH3 transport• heat transport controls NH3 loss

• Global energy gases—ammonia in context

• Tp*NiX(s) binding of ammonia

• Advantages of the organic anchorage

• Tp*NiBH4: ammine-borane hybrid

X

Cl - 490Br - 500I - 520

Tp*Tp*NiXNiX and ammonia and ammonia

λmax (nm)

NN

NNB

NN

H

Ni

X

Desrochers, P. J.; Telser, J.; Zvyagin, S. A.;Ozarowski, A.; Krzystek, J.; Vicic, D. A.Inorg. Chem. 2006, 45, 8930-8941.

Form of bound ammonia independent of X Form of bound ammonia independent of X

light absorptionmaxima

380 nm570

similar to Ni(NH3)6X2NN

NNB

NN

H

Ni

X

Form of bound ammonia independent of X Form of bound ammonia independent of X

NN

NNB

NN

H

Ni

X

NN

NNB

N

N

H

Ni NH3

NH3

NH3

+ -X

NN

NNB

N

N

H

Ni NH3

NH3

NH3

Form of bound ammonia independent of X Form of bound ammonia independent of X

+ -X

300 400 500 600 700 800 900

wavelength (nm)

Cl

Br

I

0

0.1

0.2

0.3

0.4

300 400 500 600 700 800 900

wavelength (nm)

Largest optical absorption change with iodideLargest optical absorption change with iodide

Tp*NiI

NH3 form

absorb

ance

Tp*Ni(NH3)3I(s) Tp*NiI(s) + 3NH3(g)

9.6 %

11.5 %

theory

Tp*Ni(NH3)3X(s) Tp*NiX(s) + 3NH3(g)

Cl

I

Quantitative ammonia uptake/release by Tp*Quantitative ammonia uptake/release by Tp*NiXNiX

0

2

4

6

8

10

12

280 300 320 340 360 380

temperature (K)

perc

en

t m

ass l

oss

1 K/min

0

10

20

30

40

50

300 350 400 450 500 550 600 650

temperature (K)

perc

en

t m

ass l

oss

Compare to [Ni(NHCompare to [Ni(NH33))66]Cl]Cl22

44.0 %

[Ni(NH3)3Cl2]

NiCl2

5 K/min

NH3

NH3

Halide typically along 3-fold axis of metal-ammines.Hwang, I. –C.; Drews, T.; Seppelt, K. J. Am. Chem. Soc. 2000, 122, 8486.Scheibel, P.; Prandl, W.; Papoular, R.; Paulus, W. Acta Cryst 1996 A52, 189.

3 fold symmetry

Halogen control may follow three fold axisHalogen control may follow three fold axis

NH3

NN

NN

B

NN

H

Ni

X

NH3

3 fold symmetry

Halogen control may follow three fold axisHalogen control may follow three fold axis

NH3

NH3

NN

NN

B

NN

H

Ni

X

NH3

NH3

NH3 NH3

NH3

NH3

NH3

NH3

NH3

crystalline Tp*NiX[Tp*Ni(NH3)3+][X-] ?

Directional expansion with ammonia uptake Directional expansion with ammonia uptake

Tp*NiCl

Tp*NiBr

2θ

λ = 1.541 �

IsostructuralIsostructural solids solids

powder patterns simulated using Mercury v1.4.1 CCDC

Tp*Ni(NH3)3X(s) Tp*NiX(s) + 3NH3(g)

∆H – T∆S = -RTlnK

Energetics of ammonia loss Energetics of ammonia loss

enthalpy (∆H): Ni-NH3 bond strengthNi-X bond strengthLattice alterations

entropy (∆S): mostly 3NH3(g)3(192 J/K) = 576 J/K

for Cl form ∆H = 190 kJ/mol

PNH3 ~ 0.1 bar @ 300 K

∆S ~ 576 J/K

Affinity for nitrogen substrates Affinity for nitrogen substrates

TpRCoI + 3NCMeTpRCo(NCMe)3+I�

Reinaud, O. M.; Rheingold, A. L.; Theopold, K. H. Inorg. Chem. 1994, 33, 2306-2308.TpR = TpiPrMe (in chloroform solution)

K = 45 (-22 oC)4x104 ( 27)

enthalpy (∆H = 87 kJ): Co-NCMe bond strengthCo-I bond strength

entropy (∆S = 377 J/K): mostly 3NCMe3(151 J/K) = 453 J/K

NN

NNB

NN

H

Ni NCCH3

iPr

iPr

iPr

iPr

iPr

iPr

NCCH3

NCCH3

OTf

Uehara, K.; Hikichi, S.; Akita, M. J. Chem. Soc., Dalton Trans. 2002, 3529.

Metals with high affinity for nitrogen substrates Metals with high affinity for nitrogen substrates

Stabilize anchored-nickel in a pliable environment.

Co Ni Cu

PdRh Ag

Zn

Cd

Fe

Ru

PtIr Au HgOs

Metals with high affinity for nitrogen substrates Metals with high affinity for nitrogen substrates

cobalt nickel copper zinc

• numerous transition elements with NH3 affinity• could combine storage, decomp. catalyst• variable magnetic and optical properties

• Global energy gases—ammonia in context

• Tp*NiX(s) binding of ammonia

• Advantages of the organic anchorage

• Tp*NiBH4: ammine-borane hybrid

• bulk solid: distinct ammonia uptake

• phys-isorbed:1) silica thin-layer

bulk powder2) cellulose fiber

• chemically attached: tunable ancillary ligandreduce nickel leaching

Solid supports for Tp*Solid supports for Tp*NiXNiX

Si

Si

O

Si

Si

O

Si

O

O

H

OO

O O

Si O

N N

N N

B N NH Ni

NH3

NH3

NH3

-

- -+-+

+

Silica supports for Tp*Silica supports for Tp*NiXNiX

silica

O

H

N N

N N

B N NH Ni

NH3

NH3

NH3

HC

cellulose

CH2 O

H

Cellulose supports for Tp*Cellulose supports for Tp*NiXNiX

--- -

+

++

N

N

NNB

NN

H

Ni

X

Cl Br I

Tp*NiBr on silica

Optical Monitoring of Ammonia Uptake Optical Monitoring of Ammonia Uptake

NH3 flow

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180

time (sec)

% i

nti

al

Ab

s

64% NH3

36147

NH3 at 12 mL/min, 25 oCsensor reset: 80 oC, 3 min, pure N2

Ammonia uptake by Tp*Ammonia uptake by Tp*NiNiII

0

0.1

0.2

0.3

0.4

300 400 500 600 700 800 900

wavelength (nm)

Largest optical absorption change with iodideLargest optical absorption change with iodide

Tp*NiI

NH3 form

absorb

ance

Tp*Ni(NH3)3I(s) Tp*NiI(s) + 3NH3(g)

N N

N N

C N NCH2Ni

NH3

NH3

NH3

po

lysty

ren

e

Potential covalent supports for Tp*Potential covalent supports for Tp*NiXNiX

• Global energy gases—ammonia in context

• Tp*NiX(s) binding of ammonia

• Advantages of the organic anchorage

• Tp*NiBH4: ammine-borane hybrid

AmmineAmmine--boraneborane and and NiNiPtPt

Cheng, F.; Ma, H.; Li, Y.; Chen, J. Inorg. Chem. 2007, 46, 788-794.

small % Pt in Ni catalyzes rapidhydrolysis

NH3BH3 + H2O NH4+ + BO2

- + 3H2

NiPt

A stable borohydride A stable borohydride

Tp* anchorage tempers reducing power of H-rich substrates

• inert to hot water

• stable in air

0

20

40

60

80

100

0 50 100 150 200 250time (sec)

% B

H4-

rem

ain

ing

1098

7.46

pH

Davis, R. E.; Bromels, E.; Kibby, C. L. J. Am. Chem. Soc. 1962, 84, 885.

Contrasts hydrolysis of MBH4

Desrochers, P. J.; LeLievre, S.; Johnson, R. J.; Lamb, B. T.; Phelps, A. L.; Cordes, A. W.;Gu, W.; Cramer, S. P. Inorg. Chem. 2003, 42, 7945.

N

N

N

N

B

N

N

H

Ni

HH H

B

H

FE

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

covalent anchorage

FE

Ni Ni Ni Ni

covalent anchorage

FE

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

covalent anchorage

FE

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

Ni

HHH

H

B

covalent anchorage

NH3H3NNH3 NH3H3N

NH3 NH3H3NNH3 NH3H3N

NH3

Mg(NH3)6Cl2Mg(NH3)6(BH4)2

● Tp*NiX(s) binds ammoniareversible, quantitative 3NH3:1NiX-dependent uptake, release; 3-fold axis controlcolorimetric, magnetic signals, sensor potential

● Organic anchorage advantageslowers ammonia release Tsynthetically modifiable for specialized applications

● Tp*NiBH4 stable H-rich substrateimplications for ammonia-only reactionspotential NH3BH3 interactions

Acknowledgements:Kristin Thorvilson, Chris Sutton, Josh Brown

Prof. R. Tarkka (UCA)

Prof. A. Biris (UA, Little Rock)Ms. E. Dervishi (UA, Little Rock)

$$ Petroleum Research Fund (Am. Chem. Soc.),Natl. Sci. Foundation, UCA Research Council