WYKŁAD III & IV

WYKŁAD III & IV

Magazynowanie wodoru. Kataliza niskotemperaturowego wydzielania wodoru.

A. Dlaczego wodór?

B. Trochę historii.

C. Stan obecny zagadnienia.

D. Przyszłość.

E. Najważniejsze problemy i wyzwania. Zalety magazynowania w fazie stałej.

F. Jak może pomóc teoria?

(i) Właściwości fizyczne i chemiczne wodoru.

(ii) Kontrola temperatury rozkładu wodorków binarnych. Przewidywania modelu.

(iii) Rozszerzenie na wodorki ternarne.

(iv) Kataliza heterogeniczna; synteza mechanochemiczna i klasyczna.

G. Dowiedz się więcej.

“I believe that one day hydrogen and oxygen, which together form water, will be used either alone or together as an inexhaustible source of heat and light”

(Jules Verne, The mysterious island, 1874)

THE DREAM

Why hydrogen?

Combustion of fossil fuels & other:

- Coal

- Petrol /mineral oil/  gas(oline) - Methane /natural gas/

- Recycled tires, etc.

Renewable energies:

- Solar energy - Wind energy

- Geothermal energy - Hydroenergy

Nuclear energy:

- Nuclear reactor - “Cold fusion”

Greenhouse gas (CO

)

Other pollutants (SO

, NO

etc.) Big politics

Oil plots, oil wars, etc.

Limited amount Limited geopolitics

Landscape preservation issues

Radioactive pollutants

“Atomic bomb” risk

- Hydrogen is the lightest of the elements with an atomic weight of 1.

- Liquid hydrogen has a very small density of 0.07.

- The advantage is that H stores approximately 2.6 times the energy per unit mass as gasoline.

- The disadvantage is that it needs about 4 times the volume for a given amount of energy.

a 15 gallon automobile gasoline tank contains 90 pounds of gasoline; the corresponding H tank would be 60 gallons, of weight of only 34 pounds

Pros and Cons

- When hydrogen is burned in air the main product is water (some nitrogen compounds may also be produced and may have to be controlled

- Should greenhouse warming turn out to be an important problem, the key advantage of hydrogen is that carbon dioxide is not produced when

hydrogen is burned.

Why storage in the solid state?

L. Schlapbach, A. Züttel, Nature 414, 353 (2001).

Other ways:

- physisorption (glass, sponges etc.) - liquid (price, volume, T<250 K tanks)

- compression (price, volume, permeability of containers, pressure now up to 800 bar)

Gaseous & liquid fuels vs solid fuels

?

1937 1986

2001

C CH

CH

other

nuclear, hydroelectric, wind, solar, biomass, geothermal

1999 USA

30.0 15.2

51.0 3.2

79.6 4.7 15.0

ENERGY

CO

EMISSION

OUTPUT RATE

/pounds CO₂ per 1 kWh

2.12 1.92 1.31 0.00

1998 USA

41.7

C CH

CH

20.8 36.4

other

TOTAL CO

EMISSION

31.3 15.9 23.8 16.0 13.0

C 68% ^{H 32%}

DIRTY AND CLEAN ENERGY

CONTRIB. TO THE TOTAL

ENERGY GENERATION

Hubbert’s Law

 GLOBAL ENERGY CRISIS

AROUND 2010…2050

$$$ Value

 Based on statistical data, and on prognosis of LH price, H is to take 5% of global oil market in 2010

 Global oil market is $ 700 bln/year

 H is to take $ 35 bln/year

 Tanks with MHS are thought to take $ 5 bln/year

 Invention may be sold or licensed for $ 1 bln/year

USA

Freedom /$ 150 mln incl.

$ 40 mln government share/

(fuel cells $ 340 mln!)

EUROPE

Fuchsia, Hystory, Hymosses /$ 10 mln/

JAPAN

Protium /$ ???

mln/

WE-NET /$ 4

mln p.a./

Some history

16th century – F. B. Paracelsus (Swiss…) first described an air which bursts forth like the wind 1671 – Robert Boyle published a paper in which he described the reaction between iron filings and dilute acids which results in the evolution of gas

1766 – Henry Cavendish discovers “inflammable gas from metals” (Lavoisier gives the name for it in 1783)

1783 – J. A. C. Charles suggests using hydrogen in balloons

Nov.25, 1793 – the first balloon is sent up from British soil

1807 – Dalton’s theory of atoms is published;

was the symbol used for hydrogen

May 6, 1937 – the Hindenburg tragedy Jan. 28, 1986 – the Challenger space shuttle catastrophe

1980’s – numerous explosions in the diborane factories

1839 – William Robert Grove invents fuel cell 1960’s – NASA searches for energy supplies for the spacecraft

1998–2000 Ballard Power Systems introduces 205 kW fuel cells being used in six buses in the U.S. (Chicago) and Canada (Vancouver)

May 1999 – the first public liquid–hydrogen filling station has been opened in at Munich Airport

Feb. 2001 – Eur. Comm. funds the FUCHSIA Project Feb. 2001 – a six-month tour of a fleet of ten BMW 750hL liquid hydrogen powered sedans around the globe starts in oil–producing Dubai (UAE)

Aug. 2001 – the first solar-powered hydrogen production and fueling station in the Los Angeles area opened by American Honda Motor Co.

2003 – Toyota Motor Co. is poised to be the first to offer a pure-hydrogen fuel cell vehicle to a limited public 2010/2020 – mass production of the fuel cell-powered vehicles is expected

CLEAN HYDROGEN ECONOMY FOR THE FUTURE

Hydrogen production H

(gas)

• CH₄ + 2 H₂O  CO₂ + 4 H₂

• C–H bond activation

• photoelectrochemical generation (electrolysis of water), green energy

H

(compressed) H

(liquid) H (solid chemicals) Hydrogen storage

Hydrogen combustion

• high–pressure cryogenic

tanks

• chemical reactions

H

/O

Fuel cell (Hybrid) engine

Zero–emission vehicle

Effects for the planet of the increased water

circulation = ???

Budowa Ogniwa Paliwowego (Fuel Cell).

Energia chemiczna  Energia elektryczna

małe straty cieplne, duża wydajność w por. z cyklem Carnota

ANODA /Pt Nafion® KATODA /Pt

Rodzaje ogniw paliwowych H

/O

:

- Alkaliczne (150–200

C) – wymagają użycia bardzo czystego H

i O

- Na kwas fosforowy (150–200

C) – głównie średnie do dużych aplikacji stacjonarnych

- Na stały tlenek (1000

C) – ogniwa ekstremalnie wysokotemperaturowe, tolerują względnie zanieczyszczone paliwa wodorowe

- Z membraną wymieniającą proton (Proton Exchange Membrane) lub

polimerowo–elektrolitową (Polymer Electyrolyte) Fuel Cell (60–100

C) – najbardziej rozwinięty rodzaj ogniw, największa ilość energii na jednostkę objętości ogniwa, najprawdopodobniej jedyny kandydat do zasilania

środków transportu przyszłości

- Na stopiony węglan (650

C) – ogniwa wysokotemperaturowe, mogące używać bezpośrednio paliwa kopalnego, lub nawet CO

- Protonowo–ceramiczne (700

C) – używa bezpośrednio paliw kopalnych - Bezpośrednie ogniwa metanolowe (50–100

C) – przyszłość w małych zastosowaniach moblinych

- Zn/powietrze – niski koszt, względna nieodwracalność, użycie w armii

Stacjonarne FC

Przenosne FC

Laptop FC Cell.Ph. FC

Transport/bus FC

Anchorage /Alaska/

Car of the future: BMW 750 hL presented during EURO 2000

• Yesterday: BMW 750 hL (München 2000)

6 fuel-cell busses (Chicago & Vancouver 1999-2001)

• Today: the first commercial Honda & Toyota (Japan & California 2002/3)

• Tomorrow: cheap fuel cells, cheaper H₂ (US & Canada 2010)

Who does not pick up this subject NOW, most

probably would not have chance to work on it at all.

COMMANDEMENTS OF HYDROGEN STORAGE

(i) High storage capacity: minimum 6.5 wt % abundance of hydrogen and at least 65 g/l of hydrogen available from the material;

(ii) T

= 60–120

C;

(iii) Reversibility of the thermal absorption / desorption cycle:

low temperature of hydrogen desorption and low pressure of hydrogen absorption (a plateau pressure of the order of few bars at room temperature), or an ease of nonthermal

transformation between substrates and products of decomposition;

(iv) Low cost;

(v) A nontoxic, nonexplosive, inert etc., storage medium.

EXAMPLES OF CHEMICAL HYDROGEN STORES

1. PdH_0.6: 0.6 wt%, excellent reversibility, $ 1000/oz, >$1mln/1kg H 2. NaH: 4.2 wt%, good reversibility, T_dec > 425 ^oC

3. NaAlH₄ & TiO₂: 5.5 wt%, T_dec > 125 ^oC, reversibility OK 4. MgH₂: 7.6 wt%, T_dec > 330 ^oC, poor reversibility

5. “Li₃Be₂H₇“: 8.7 wt %, T_dec > 300 ^oC, toxicity, cost

6. NaBH₄/H₂O_(l): 9.2 wt%, expensive Ru catalyst, no reversibility 7. AlH₃: 10.0 wt %, very cheap Al, T_dec > 150 ^oC, no reversibility 8. H₂O_(l): 11.1 wt%, liquid, thermal decomposition difficult

9. MeOH_(l): 12.5 wt%, toxic liquid, activation difficult 10. LiH: 12.6 wt%, T_dec > 700 ^oC

11. NH_3(l): 17.6 wt%, large N – H bond activation barrier

11. BeH₂: 18.2 wt%, extremely toxic, T_dec > 250 ^oC, no reversibility 12. CH₄: 25.0 wt%, gas, thermal activation very difficult

13. Carbon nanotubes: ??? Wt%, ???

Compare to Mg₂NiH₄: 3.6 wt% (ii, iii, iv, v)

(ii,iii, v) (iii, iv, v) (ii, iii, iv, v)

(i, iv, v) (i, iii) (i, ii, iv, v)

(i, iv, v) (i, iii, iv, v)

(i, iv) (i, iv, v)

(i, iv) (i) (i, iv) (i, ii, iii, v?)

0 20 40 60 80 100 120 140 160

0 5 10 15 20 25

gravimetric H content [wt%]

volumetric H density [g/l]

MAIN CHEMICAL PLAYGROUND

Problems with setting of the position of H in the periodic table of chemical elements

H as H⁺:

• H’s I_P is similar to that for Cl.

• “Dimension”

of proton is very

different depending on the

solvating agent;

spectrum of energies of H bond is very broad.

H as H⁰.

• It is a gaseous nonmetal. Has never been metallized in the solid state.

• H radical has enormous tendency for pairing.

Bonding energy is 436 kJ/mole, and it is slightly smaller than those of O₂ or P₂.

Difference of properties for three available oxidation

states of H is the largest among all chemical elements at their typical oxidation states

(derivative of energy upon charge is large).

H as H^–:

• Creates metal hydrides (H as hydride anion) much easier than other Group 1 elements.

• Dimension of H^– is very

susceptible to the polarization properties of the metal, and most often it is in between of

those for Cl^– and F^–.

H

EVOLUTION REACTION PATHWAY

Reaction path for evolving H₂ from a H–containing

material. Elongation of the M–H bonds occur along R_M–H coordinate, and the pairing of two H atoms in a H₂

molecule proceeds along the R_H–H coordinate. The actual reaction coordinate is a combination of these two.

WHICH REDOX EQUILIBRIUM TO PLAY?

E /eV +13.60

0.0

0.75

+1 0 1

n

Fig.2. The dependence of the electronic energy of the Hⁿ species on the oxidation state of hydrogen, n. The hardness (the derivative of energy on the electron density) is schematically shown as dotted lines. Note that the hardness of Hⁿ species strongly decreases in the direction:

H^I+ > H⁰ > H^I–.

H^I/H₂ or H⁺¹/H₂

I_P /kJ mol^–1

E_A /kJ mol^–1

I_P /kJ mol^–1

E_A /kJ mol^–1

H

1312 H

72.8 H

1312 H

72.8 Li

520.2 Li

59.6 F

1681 F

328 Na

495.8 Na

52.8 Cl

1251.2 Cl 349 K

418.8

K 48.4

Br 1139.9

Br 324.6 Rb

403.0

Rb 46.9

I 1008.4

I 295.2 Cs

375.7

Cs 45.5

At 920

At 270.1

H^– H⁰

H⁺

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 1

H

2 He 2 3

Li 4 Be

5 B

6 C

7 N

8 O

9 F

10 Ne 3 11

Na

12 Mg

13 Al

14 Si

15 P

16 S

17 Cl

18 Ar 4 19

K

20 Ca

21 Sc

22 Ti

23 V

24 Cr

25 Mn

26 Fe

27 Co

28 Ni

29 Cu

30 Zn

31 Ga

32 Ge

33 As

34 Se

35 Br

36 Kr 5 37

Rb

38 Sr

39 Y

40 Zr

41 Nb

42 Mo

43 Tc

44 Ru

45 Rh

46 Pd

47 Ag

48 Cd

49 In

50 Sn

51 Sb

52 Te

53 I

54 Xe 6 55

Cs

56 Ba

71 Lu

72 Hf

73 Ta

74 W

75 Re

76 Os

77 Ir

78 Pt

79 Au

80 Hg

81 Tl

82 Pb

83 Bi

84 Po

85 At

86 Rn 7 87

Fr 88

Ra 103

Lr 104 Rf 105

Db 106

Sg 107

Bh 108

Hs 109

Mt 110

Uun 111

Uuu 112

Uub 113

Uut 114

Uuq 115

Uup 116

Uuh 117

Uus 118 Uuo 57

La

58 Ce

59 Pr

60 Nd

61 Pm

62 Sm

63 Eu

64 Gd

65 Tb

66 Dy

67 Ho

68 Er

69 Tm

70 Yb 89

Ac

90 Th

91 Pa

92 U

93 Np

94 Pu

95 Am

96 Cm

97 Bk

98 Cf

99 Es

100 Fm

101 Md

102 Nb 7

N

Niemetal 3

Li Metal 5

B

Niemetal zmetalizowany pod wysokim p 85

At Brak prób, teoretycznie w zasięgu metalizacji 1

H

Zmetalizowany tylko w fazie ciekłej

ATTEMPTS OF H METALLIZATION

H

• It should be easy to play the H

/H

equilibrium;

• It is much more difficult to play the H

/H

one;

• It is quite difficult to play the 2H

/H

equilibrium;

• It is the most difficult to play the (H

,H

)/H

one.

Which species are to be involved in the charging/recharging process of the Hydrogene Storage Material?

H^–1  H₀ + e^ (H⁰ = +0.75 eV) (1a)

H⁺¹ + e^ H⁰ (H⁰ = –13.60 eV) (1b)

2 H⁰  H₂ (H⁰ = –4.52 eV) (1c)

H⁺¹ + H^1 H₂ (H⁰ = –17.37 eV) (1d)

Standard enthalpies of formation Hf0 [kJ/mol] of binary hydrides of the main group elements.

MH MH₂ MH₃ MH₄ MH₃ MH₂ MH

Li -116.3

Be -18.9

B^[1]

+36.4

C -74.6

N -45.9

O -285.8

F -273.3 Na

-56.5

Mg -75.2

Al -46.0 +92^[1,2]

Si +34.3

P +5.4

S -20.6

Cl -92.3 K

-57.7

Ca -181.5

Ga

???^[3]

+118^[1,2]

Ge +90.8

As +66.4

Se +29.7

Br -30.3 Rb

-52.3

Sr -180.3

In

???^[3]

+175^[1,2]

Sn +162.8

Sb +145.1

Te +99.6

I +26.5 Cs

-54.2

Ba -177.0

Tl^#

???^[3]

+245^[1,2]

Pb +181.1^[2]

+251.5^[4]

Bi +230.6^[4]

Po +188.6^[4]

At +104.8^[4]

[1] Molecular dimer, M₂H₆.

[2] Theoretical value.

[3] Value for solid hydride is not known. This hydride certainly decomposes below 0 ^oC, and a H_f⁰ value (standard conditions) cannot be measured.

[4] Extrapolated from experimental values.

M

+ n H

 M + n/2 H

Chemical rationale behind the metal/hydrogen avoided crossing curve.

Size, electric charge, orbital energy, hardness, and standard redox potential.

–12.18 -0.14

1.34 BeH₂

–10.10 -0.24

1.73 MgH₂

–8.61 -0.34

2.15 CaH₂

–7.98 -0.38

2.33 SrH₂

–12.18 -0.14

1.34 BeH₂

–10.10 -0.24

1.73 MgH₂

–8.61 -0.34

2.15 CaH₂

–7.98 -0.38

2.33 SrH₂

molecule R₀/Å q(H)/e HOMO/eV

250 –1.97

0.59 Be

327 –2.36

0.86 Mg

600 –2.84

1.14 Ca

675 –2.89

1.32 Sr

250 –1.97

0.59 Be

327 –2.36

0.86 Mg

600 –2.84

1.14 Ca

675 –2.89

1.32 Sr

atom R_cat/Å E⁰/V T_dec /^oC

Ga⁺ > Ga⁰ > Ga^–

[GaH₂][BH₄] < [GaH₃]₂ < LiGaH₄ –35 ^oC, –15 ^oC, 50 ^oC

Electronegativity vs the total charge & substituents

B⁰ > B [BH₃]₂ < LiBH₄ +40 ^oC, +275 ^oC

Zn⁺² > ZnI¹⁺

[ZnH₂] < [ZnHI]

+90 ^oC, +110 ^oC Ga⁺³ > GaCl²⁺ > GaCl₂¹⁺

[GaH₃]₂ < [GaClH₂]₂ < [GaCl₂H]₂ –15 ^oC, –15 ^oC, +50 ^oC [AlH₃] < Li[Al₂H₇^–] < LiAlH₄

150 ^oC, 160 ^oC, 165

MgH₂ < Sr₂[MgH₆] < Ba₂[MgH₆] 327, 377, > 427 ^oC [InH₃] < InH₄^–

???, –30 ^oC

Zn⁺² > Zn^–2 [ZnH₂] < K₂[ZnH₄]

+90 ^oC, +407 ^oC

As⁺⁵ > AsPh₄¹⁺

[AsH₅] < [AsPh₄H]

???, obtained Na₂[BeH₄] > [BeH₂] > Be[BH₄]₂

+380 ^oC, +250 ^oC, +25 ^oC [GaH][BH₄]₂ < [GaH₂][BH₄] < [GaH₃]₂ < LiGaH₄

–73 ^oC, –35 ^oC, –15 ^oC, +50 ^oC

[Bi⁵⁺] > [BiCl₄¹⁺]

unknown, [BiCl₄¹⁺][H^1–] known as H¹⁺Bi^IIICl₄

-200 -100 0 100 200 300 400 500 600 700 800

-3.5 -2.5 -1.5 -0.5 0.5 1.5 E⁰ / V

Tdec / o C

H₂/2H^ H^0/H^

Na⁺ Li⁺

Er³⁺

Ca²⁺

Be²⁺, Pu³⁺

Mg²⁺

Zn²⁺

Al³⁺

V²⁺

Ga³⁺

Sn⁴⁺

Hg²⁺

Sb³⁺

Ba²⁺, Sr²⁺

Y³⁺

U³⁺

B³⁺P³⁺

Cd²⁺

BaRuH₉ &

Cs₃RuH₁₀ vs RuH₇

Mg₂FeH₆ vs FeH₂

M₂PtH₆ vs PtH₄

…

[M^IIIH₄^1–], M=Cr, Eu, Yb [CdH₄^2–]

????????

[HgH₄^2–] [PtH₆] M₂Pd⁰H₂ M=Li,

Na, & Sr₂Pd⁰H₄ (1.674–1.676 Å) M₂Pd^IIH₄ M=K, Rb, Cs (1.625–

1.64 Å )

M₂Pt^IIH₄ M=Na, K, Rb, Cs

(MH)₂Pt^IIH₄ M=Sr, Ba

M₂Pt^IVH₆ M=K, Rb, Cs

d¹⁰ = Au¹⁺ [AuCl₂^–] d⁸ = Au³⁺ [AuCl₄^–] d⁶ = Au⁵⁺ [AuF₆^–]

Predictions of the T

vs E

relationship for binary hydrides

T

= –31.396 x

– 41.078 x

– 75.231 x – 7.3957

R

= 0.9777

Hydride Redox pair E⁰ /V T_dec /^oC Hydride Redox pair E⁰ /V T_dec /^oC ScH₃^[1] Sc^III/Sc⁰ 2.03 239 WH₆^[1,2] WO₃/W₂O₅ 0.029 -5

ThH₄^[1,3] Th^IV/Th⁰ 1.83 185 TiH₄^[1] TiO₂/Ti^III +0.1 -15

HfH₄^[1] Hf^IV/Hf⁰ 1.70 156 SH₆^[4] HSO₄^/H₂SO₃ +0.16 -21 ZrH₄^[1] Zr^IV/Zr⁰ 1.55 127 NpH₄ Np^IV/Np^III +0.18 -22 PaH₄^[5] Pa^IV/Pa^III 1.46 113 UH₆^[1] UO₂²⁺/U^IV +0.27 -31 YbH₃ Yb^III/Yb^II 1.05 63 BiH₃ Bi^III/Bi⁰ +0.317 -36^[6]

TaH₅^[2] Ta^V/Ta⁰ 0.81 43 PoH₂ Po^II/Po⁰ +0.37 -42 UH₄^[1] U^IV/U^III -0.52 25 UH₅^[1] UO₂⁺/U^IV +0.38 -44 TiH₃^[1] Ti^III/Ti^II 0.37 16 SH₄^[4] H₂SO₃/S⁰ +0.50 -59 EuH₃^[1] Eu^III/Eu^II 0.35 15 AsH₅ H₃AsO₄/HAsO₂ +0.560 -68 InH₃^[1] In^III/In⁰ 0.338 15 TeH₄ Te^IV/Te⁰ +0.57 -69 PH₅^[2] H₃PO₄/H₃PO₃ 0.276 11 SbH₅ Sb₂O₅/SbO⁺ +0.605 -75 VH₃ V^III/V^II 0.255 10 MoH₆^[1] H₂MoO₄/MoO₂ +0.646 -82 WH₄^[1] WO₂/W⁰ 0.119 1 NpH₅ NpO₂⁺/Np^IV +0.66 -84 PaH₅ PaO(OH)₂⁺/Pa^IV 0.1 0 AtH HAtO/At⁰ +0.7 -91 NbH₅^[2] Nb₂O₅/Nb^II 0.1 0 TlH₃ Tl^III/Tl⁰ +0.72 -95

[1] Species isolated in the noble gas matrixes.

[2] Organophosphine–stabilized hydrides have been obtained.

[3] Mixed–valence hydrides exist (Th₄H₁₅, Yb₃H₈, Eu₃H₇).

[4] Theoretical predictions of kinetic stability exist.

[5] Mentioned as a reactant in one study.

[6] Recently isolated at –55 ^oC; fast decomposes at –40 ^oC.

T

vs H

for some binary and ternary hydrides

R² = 0.974

R² = 0.996 -150

-100 -50 0 50 100 150 200 250 300 350

-150 -50 50 150

delta H_dec Tdec

binary Group 13 hydrides

ternary Al hydrides predictions of E0 for In, Tl

Aspects of catalysis in hydrogen storage

Energy

Reaction coordinate MH_x

M + x/2 H₂

A)

B)

C) D)

Reaction path for H₂ evolving from different MHS.

A) Thermodyn. unstable MHS with low activation barrier and low T_dec; stores H irreversibly;

B) Thermodyn. stable MHS with high activation barrier and high T_dec; stores H reversibly;

C) Thermodyn. slightly stable MHS with intermediate T_dec; stores H irreversibly;

D) target : catalytically–

enhanced thermodyn.

slightly stable MHS with low T_dec; stores hydrogen reversibly.

Vertical arrows symbolize activation barrier for the

decomposition process.

Experimental pathway

Hydrogen Store Catalyst

Target: doped MHS

Mechanochemical synthesis (high-energy ball-milling)

Wet (classical) synthesis

T

=? (TGA) H

reabsorption (PCI) Lifetime=? (PCI)

thermodynamics kinetics

Price=?

Goal fulfilled

Efficient Low–temperature

Reversible Terrorist–proof Solid Hydrogen

Store

--- CH₄: Gas, T_melt = –183 ^oC, T_dec = +680 ^oC

NH₄⁺BH₄^–: Solid, T_dec = –40 ^oC

--- Cyclohexane is thermally stable liquid

[GaH₂NH₂]₃ decomposes at +150 ^oC to GaN and H₂ ---

Benzene C₆H₆: H_f°gas = +82.93 kJ mol^–1

Borazine N₃B₃H₆: H_f°gas = –510.03 kJ mol^–1 ---

Electronegativity perturbation vs the H…H coupling equilibrium

Conclusions

1. One should preferably play the H

/H

equilibrium (metal hydrides) 2. Use light weight hydrides of strongly electropositive elements

(thermodynamically reversible) as a main hydrogen store.

3. Play on the electronegativity of a metal center by use of various ligands (including additional hydride ligands).

4. Use compounds of more electronegative metals as catalyst of H

evolution. Tune T

.

5. Provide that catalyst is not irreversibly reduced by hydrogen store, and by corresponding metal product.

6. Attempt play on the (H

,H

)/H

equilibrium if price of hydrogen store is very low (irreversibility does not matter) and if environment pollution is small. Forget the plasma induced H

reabsorption.

7. Try to solve the problem asap.

Hydrogen storage in carbon: graphite, fullerenes, nanotubes.

Modification: inorganic nanotubes

Non–reproducible claims of:

i) Up to 13 wt % H in single wall nanotubes (Nature 1997, 386, 377; Science 1999, 286, 1127, Carbon 1999, 37, 1649)

ii) Up to 20 wt % H in alkali metal–doped nanotubes (Science 1999, 285, 91).

Problems:

i) Lack of homogenity

ii) Low active material content

iii) High price of C nanotubes (CNT)

iv) Simple graphitic sheets & doped graphite:

low H storage efficiency

v) Fullerenes: irreversible storage C₆₀H₄₄.

4 wt % H at 9 bar in ‘collapsed BN_NTs (J. Amer. Chem. Soc. 2002, 124,

14550).

(Photo)electrolysis of water

bateria słoneczna

h

elektryczność H

O

H

O

inne

odnawialne E

H

O h

TiO₂:C – 10 times better

efficiency of photoelectrolytic splitting of water than pure TiO₂ (Nature, 2002)

Utsira (Norway) 2003 Similar projects:

i) windy islands of northern

Scotland,

ii) sunny costs of Florida,

iii) and geothermal energy (Iceland – model hydrogen energy-based EU society!)

Activation of C–H, C–C, H–H and NN bonds.

: ^M

[L] + H–CH

 M

[L](CH

)(H

), same for H–C

H

Oxidative & non–oxidative C–H bond activation:

M

[L]( : ^H

) + H–CH=CH

 M

[L](C

H

), M=Ru,Rh,Ta etc.

similar scheme for the C–C and H–H bonds

vide: agostic interactions

C=O & CO bond activation:

O=C=O  –O–(C=O)–

|CO|  –(C=O)–

Review on C–H activation:

Nature 417

(2002) 507–514

homolytic activation

heterolytic activation

Complexes of molecular H–H.

Complexes of molecular NN.

Find out more – Be up to date!

Hubbert’s peak & energy consumption:

• http://www.hubbertpeak.com/midpoint.htm

• http://www.trenton.edu/~energy/altfuel/Hydrogen.htm

• http://www.oilcrisis.com/laherrere/opec95.htm

• http://www.eia.doe.gov/oiaf/ieo/index.html

• http://www.energy.gov/dataandprices/index.html

• http://www.cato.org/pubs/pas/pa-280.html Hydrogen production & storage:

• http://www.eren.doe.gov/hydrogen/basics.html

• http://www.eren.doe.gov/RE/hydrogen.html

• http://www.ornl.gov/ORNL/Energy_Eff/power-h2.html

• http://www.clean-air.org/ahafaq.html

• http://www.etde.org/html/hyd/hydhome.html

• http://starfire.ne.uiuc.edu/~ne201/1995/archer/hydro.html

• http://refining.dis.anl.gov/oit/toc/h2proc_8.html

• http://www.hydrogen.org/Wissen/NHF97.htm#4. Hydrogen Storage

• http://naftp.nrcce.wvu.edu/techinfo/altfuels/H2/Hydrogen.html

• http://ceh.sric.sri.com/Public/Reports/743.5000/

• http://home.powertech.no/magneh/meyer/hydrogen.htm

• http://www.e-sources.com/hydrogen/storage.html

• http://www.h2eco.org/

Press & news:

• http://www.hfcletter.com/

• http://www.h2fc.com/defaultNS4.html

• http://www.cnn.com/2000/NATURE/09/15/hydrogen.car/

• http://www.csmonitor.com/2002/0131/p13s01-stss.html

• http://www.chemweb.com/alchem/articles/1023977425407.html

Scientific programs:

• http://www.ca.sandia.gov/CRF/03_hydrogen.html

• http://www.nrel.gov/nrel_research.html

• http://www.bham.ac.uk/FUCHSIA/home.htm

• http://www.spacefuture.com/archive/liquid_hydrogen_industry_a_key_for_space_tourism.shtml

• http://www.eren.doe.gov/

• http://www.bbsrc.ac.uk/science/initiatives/supergen.html

• http://www-ew.ike.uni-stuttgart.de/ewproject/ewktr821e.htm Companies:

• http://www.jmcusa.com/mh1.html

• http://www.ergenics.com/

• http://www.ovonic.com/

• http://www.shell.com/home/Framework?siteId=hydrogen-en

• http://www.genesis.rutgers.edu/Partners/millenium.html

• http://www.azhydrogen.com/mg_25.html

• http://www.ballard.com/

• http://www.multishop.pp.ru/dmoz/Science/Technology/Energy/Hydrogen

• http://www.uscar.org/pngv/

• http://www.herahydrogen.com/flash.html

• http://www.ballard.com/tD.asp?pgid=32&dbid=0 Fuel cells:

• http://inventors.about.com/library/weekly/aa090299.htm?once=true&

• http://rhlx01.rz.fht-esslingen.de/projects/alt_energy/storage/fuelcell/fuelcell.html Conferences:

• http://www.grc.uri.edu/programs/2001/hydrmet.htm

Find out more – cd.