Highly efficient and stable CeNiHZOY nano-oxyhydride catalyst for H2 production from ethanol at room temperature

Article abstract of DOI:10.1002/anie.201102617

The CeNiH_ZO_Y oxyhydride compound is an exceptional catalyst that totally converts ethanol at 60°C and produces H₂ in the presence of water and oxygen. The H₂ fraction of the gas-phase products is about 50% (see picture; c: conversion, p: production). The oxyhydride compound is formed by in-situ activation of CeNiO_Y with H₂ at 250°C. The presence of hydride species in the catalyst is evidenced by inelastic neutron scattering.

Full text of DOI:10.1002/anie.201102617

DOI: 10.1002/anie.201102617
Heterogeneous Catalysis
Highly Efficient and Stable CeNiHZOY Nano-Oxyhydride Catalyst for
H2 Production from Ethanol at Room Temperature**
Cyril Pirez, Mickaꢀl Capron, Hervꢁ Jobic, Franck Dumeignil, and Louise Jalowiecki-Duhamel*
Dedicated to the Fritz Haber Institute, Berlin, on the occasion of its 100th anniversary
Hydrogen and fuel cells are crucial to any clean energy policy.
At the international level, hydrogen has been proposed as a
major energy vector that could contribute to the reduction of
the global dependence toward fossil fuels and to the lowering
of greenhouse-gas emissions and atmospheric pollution.[1] At
present steam reforming of hydrocarbon compounds, that is,
natural gas, is the most commonly used and generally the
most economically competitive method for hydrogen produc-
tion. Producing hydrogen in a sustainable way from an
environmentally friendly and promising renewable source of
hydrogen is highly desired for the growing fuel-cell technol-
ogy and industrial needs. Bioethanol obtained from biomass
has been proposed as a promising renewable source of
hydrogen for these systems by simultaneously addressing the
greenhouse-effect issue.[2] In such a context, it is today a major
challenge to provide low-cost catalysts that are able to
cations, which require high hydrogen selectivity and rapid
response.
C2H5OH þ 3 H2O ! 6 H2 þ 2 CO2
C2H5OH þ 1:5 O2 ! 3 H2 þ 2 CO2
ð1Þ
ð2Þ
Here, we show that H2 is produced from ethanol in a
sustainable way by taking advantage of the chemical energy
delivered from the reaction between hydride species of the
nano-oxyhydride catalyst and O2. We have successfully
developed a new technology that saves energy because of
the exothermic reaction between hydride species of the
catalyst and O2 (chemical energy) and the exothermic
reaction between ethanol and O2 (partial oxidation). The
chemical reactions provide the energy necessary to convert
ethanol and produce H2. To this purpose we developed a
highly active, selective, stable, and cost-effective catalyst. We
report that the low-cost CeNiHZOY nano-oxyhydride catalyst
ꢀ
efficiently break the C C bond from bioethanol. Materials,
such as catalysts or electrocatalysts that are able to activate
fuels like H2, and alcohols are absolutely required for the
development of new technologies.[3]
ꢀ
efficiently split the C C bond of ethanol at room temper-
ature, which is a major advance in the field. The CeNiHZOY
nano-oxyhydride catalyst has the remarkable ability of
simultaneously activating ethanol, producing H2, and provid-
ing hydride species to sustain the chemical reaction with O2.
The endothermic steam reforming of ethanol (SRE) given
by Reaction (1) requires energy input,[4] which leads to high
operation costs and to a nonadvantageous global CO2
balance. However, the required energy can be supplied by
adding some oxygen or air in the feed. This enables the
exothermic partial oxidation of ethanol (POE) given by
Reaction (2),[5] during which a portion of ethanol is burnt,
providing the energy needed to simultaneously realize the
SRE in Reaction (1).[6] Such a technology would be suitable
for onboard hydrogen production, that is, for mobile appli-
The active CeNiHZOY nano-oxyhydride catalyst is
obtained by in situ pretreatment of a CeNiOY nanocompound
with H2 at 2508C for 10 h. The CeNiHZOY catalyst (0.03 g of
the starting material) has been tested for hydrogen produc-
tion from ethanol in simultaneous presence of water and O2
(the ratio of EtOH/H2O/O2/N2 was 1:3:1.6:1.3). Figure 1
[*] Dr. C. Pirez, Dr. M. Capron, Prof. F. Dumeignil,
Dr. L. Jalowiecki-Duhamel
Universitꢀ Lille Nord de France, 59000 Lille (France)
and
CNRS UMR8181, Unitꢀ de Catalyse et Chimie du Solide, UCCS
59655 Villeneuve d’Ascq (France)
E-mail: louise.duhamel@univ-lille1.fr
Homepage: http://uccs.univ-lille1.fr
Prof. F. Dumeignil
Institut Universitaire de France, Maison des Universitꢀs
10, Boulevard Saint-Michel, 75005 Paris (France)
Dr. H. Jobic
IRCELyon Institut de Recherche sur la Catalyse
et l’Environnement de Lyon
2 avenue Albert Einstein, 69626 Villeurbanne Cedex (France)
^
Figure 1. Ethanol conversion (c, ) and distribution of gas-phase
~
~
*
*
products (p: production, H2 , CO2 , CO , CH4 , and CH3CHO &
in mol%) obtained versus time over the CeNiHZOY oxyhydride catalyst
(0.03 g) with an oven temperature at 608C. The composition of the
reaction mixture EtOH/H2O/O2/N2 is 1:3:1.6:1.3 and the measured
reaction temperature is of 2808C.
[**] This work was financially supported by the CNRS, the French
Ministry (C. Pirez grant), and the Institut Laue Langevin (ILL)
Grenoble, France.
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Communications
shows the ethanol conversion rate and the molar fraction of
H2O/EtOH ratio was kept at 3:1. Each point reported in
Figure 2 is obtained after 5 h of reaction over a fresh solid
(0.2 g) pre-treated in H2 at 2508C. For an O2/EtOH ratio
larger than 1:1, the variation of temperature (DT) is almost
constant (increase of about 1208C) at total conversion of
ethanol. It seems that there is a limitation because of the total
conversion of ethanol. As presented in Figure 1 with a much
lower catalytic mass (0.03 g) and a ratio of 1.6:1 the variation
of temperature is much higher. So the limitation is a result of
the low proportion of ethanol relative to the catalytic mass.
Without pre-treatment of the catalyst with H2 under exactly
the same conditions, we did not observe a variation of
temperature. Therefore, even if the contribution of the
exothermic partial oxidation reaction must also be consid-
ered, this contribution cannot explain the results obtained.
Moreover, to our knowledge such a phenomenon has not
been reported in the literature.
H2 calculated relatively to the gas-phase products. The results
reported at a reaction temperature of 2808C are obtained
with a much lower oven temperature of 608C. The ethanol
conversion is almost complete at a H2 production of about
45% relative to all gas-phase products. The other products are
mainly CO2 and CO (Figure 1). To our knowledge, the
obtained results are the best results reported up-to-date for a
low-cost catalyst.[4a] It must be noted that the catalytic
reaction must be initiated at 2308C. After an induction
period of a few minutes (around 5 min.), the temperature
increases and then only a small energy supply is needed to
maintain the reaction, and therefore the oven temperature is
lowered to 608C. The exothermic reaction between hydride
species of the catalyst and O2 (chemical energy) and the
exothermic reaction of ethanol and O2 is used to provide the
energy necessary to convert ethanol and produce H2. The
activity is remarkably stable after 70 h of reaction even if
some solid carbon is formed (63 mg per gram of catalyst and
hour). The stability is certainly due to the filamentous type of
carbon formed.
Compared to previous results reported by us under
conditions of SRE, the conversion is largely increased when
adding O2 to the reaction mixture. Even if a high and stable
activity (5 h) was already observed under conditions of SRE
at a conversion rates of 50% of ethanol and about 50% of H2
formed at 2508C over 0.2 g of the catalyst.[7] The high activity
of the cerium–nickel-based catalysts has already been
reported and attributed to the existence of strong interactions
between Ni and Ce species.[4a,7] In the laboratory, CeNiXOY
mixed oxides were largely studied because of the strong
interactions existing between Ni and Ce species in the solid.
Redox processes between Ce4+, Ce3+, Ni0, and Ni2+ were
shown. The active Ni species are characteristically and easily
reduced and reoxidized because of their close interaction with
Ce species, for which particular active sites have been
proposed.[8]
Addition of O2 leads to an increase in the conversion of
ethanol while the percentage of formed H2 remains almost
constant up to an O2/EtOH ratio of 1.2:1 (Figure 2). For
higher O2/EtOH ratios, the formation of H2 slightly decreases.
The relative quantities of acetaldehyde, CO, and methane
decrease when the O2 concentration is increased (Figure 3).
Figure 3. Product distribution (P) obtained over CeNiHZOY in a EtOH/
H2O/O2 reaction mixture with an oven temperature fixed at 2008C.
~
*
CH3CHO (&), CH4 ( ), and CO ( ) in the gas phase (mol%). The
The ethanol conversion and hydrogen production have
been studied versus the O2/EtOH ratio, that is, the O2
concentration, because the ethanol concentration was kept
constant. An increase in temperature when the O2 concen-
tration was increased has also been measured (Figure 2).
Therefore, the oven temperature was fixed at 2008C and the
ratio of H2O/EtOH is kept at 3:1.
This is also the case for acetone (not reported) formed in
small quantities (2.5%) only at an O2/EtOH ratio of 0.5:1. As
expected, the CO2 quantity (not reported) increases from 30
to 60% at the highest O2 concentration. An O2/EtOH ratio of
about 1.2:1 leads to a high ethanol conversion with the highest
yield of H2 but some acetaldehyde is still obtained. At an O2/
EtOH ratio of 1.6:1 a high yield of H2 is obtained without
formation of acetaldehyde, which is a good compromise.
Dehydrogenation of ethanol produces acetaldehyde and
H2 [Reaction (3)], whereas decomposition of ethanol (and/or
acetaldehyde) produces methane, carbon monoxide, and
hydrogen [Reaction (4)].
C2H5OH ! C2H4O þ H2
ð3Þ
ð4Þ
C2H5OH ! CH4 þ CO þ H2
~
^
Figure 2. Ethanol conversion (c; ) and H2 production (p; ) over
CeNiHZOY (0.2 g) in a mixture of EtOH/H2O/O2. The ratio of H2O/
EtOH is kept at 3:1. The oven temperature is fixed at 2008C and the
The diffraction patterns obtained from the calcined
CeNiOY catalyst (before pretreatment with H2) suggests the
variation of temperature (DT) is measured ( ).
*
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Angew. Chem. Int. Ed. 2011, 50, 10193 –10197

presence of two phases, a ceria-like phase (JCPDS file: 34-
0394) and a crystallized NiO phase (JCPDS file: 4-0835;
Table 1).
cerium–nickel system, in addition to the route described
above, the homolytic dissociation of H2 on Ni0 has also been
considered, and different hydrogen species can coexist.[8a]
However, the in situ XRD analysis of H2 does not evidence
Ni0 species at a temperature of 2508C for 10 h and even at
2608C for 10 h (Figure 5). On the studied compound, metallic
Ni is observed by XRD for a treatment with H2 at 3008C.
Table 1: Surface area and crystallites size.
Catalyst
Ni
[wt%]
SA[a]
d (CeO2)[b]
[nm]
d (NiO)[b]
[nm]
[m2 gꢀ1
]
CeNiOY
20
94
5
10
[a] BET specific surface area. [b] Deduced from XRD.
In previous studies, we reported that some small NiO
nanoparticles (around 2 nm)[8d] coexist with larger NiO
nanoparticles (10 nm) observed by XRD (Table 1).[8a] There-
fore, the CeNiOY catalyst, which possesses a specific surface
area of 94 m2gꢀ1, corresponds to a nanocompound of CeO2
particles about 5 nm in diameter and NiO nanoparticles of
different sizes. CeO2 can be modified by the insertion of Ni
species but it has been shown that for this specific Ni content
(CeNiOY), the solid solution is obtained in low proportion.[8a]
To activate Ni species belonging to small NiO nanoparticles
(and/or in solid solution), the required temperature for
pretreatment with H2 corresponds to the first temperature-
programmed reduction (TPR) peak (Figure 4).[7a] It has been
shown that a higher temperature for pretreatment with H2
leads to a decrease in the conversion of ethanol at low
temperature under conditions of SRE.[7b]
Figure 5. XRD patterns of CeNiOY obtained during in situ reduction in
H2 at a) 2508C, b) 2508C for 10 h, c) 2608C, and d) 2608C for 10 h.
*
Peaks assigned to CeO2 (+) and NiO ( ).
The insertion of hydride species into the solid is well
shown by inelastic neutron scattering (INS).[10] The treatment
with H2 generates an increase in the level of the INS spectrum
as well as the emergence of new peaks associated to vibration
bands of hydrogen (Figure 6). The level of the spectrum is
Figure 4. Temperature-programmed reduction of CeNiOY in H2.
Figure 6. INS spectrum of CeNiHZOY (red solid line) treated in H2 at
2508C after subtraction of the the CeNiOY spectrum, and INS
spectrum of CeNiHZOY after oxidation and subtraction of the CeNiOY
spectrum (dashed line).
The pretreatment with H2 at 2508C leads to the formation
of an oxyhydride compound. As a matter of fact, chemical
titration of the hydrogen species stored in the solid has shown
previously that CeNiXOY mixed oxides store high quantities of
hydrogen, and among the studied series, the CeNi1OY com-
pound has been found to store the highest quantity of reactive
hydrogen.[8b,c] To explain the process of hydrogen storage it
has been proposed that hydrogen can be heterolytically
dissociated at an anionic vacancy and a O2ꢀ species of the
catalyst [Reaction (5)]
proportional to the hydrogen content. The INS spectrum of
CeNiOY (treated in vacuum at 2008C) evidences some
hydrogen species with vibration bands at about 250, 400,
and 630 cmꢀ1, which are already present in the calcined
compound.[11] As a matter of fact, this mixed oxide contains
hydroxy groups before treatment with H2.
Two new intense and large bands at about 460 and
870 cmꢀ1 are observed on the catalyst treated with H2 because
of the insertion of different hydrogen species. To observe
more precisely the hydrogen species created by treatment
ð5Þ
O
2ꢀMnþ& þ H2 ! OHꢀMnþHꢀ
with &: anionic vacancy and Mn+: cation. It has been reported
that metallic nickel adsorbs hydrogen;[9] therefore, for the
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Communications
with H2 for activation, the INS spectrum of CeNiOY in
proposed for heterolytic dissociation of H2 [Reaction (5)], an
active site involving an anionic vacancy and an O2ꢀ species of
the solid can be envisaged for the heterolytic dissociation of
ethanol [Reaction (7)].
Figure 6 has been subtracted from that of CeNiHZOY (treated
in H2 at 2508C). The hydride species related to the peak at
about 460 cmꢀ1 appear clearly after treatment with H2 at
2508C. The large band at 870 cmꢀ1 was assigned to hydrogen
species interacting with metallic nickel Ni0 species.[11] Even if
Ni0 species are not observed by XRD, some small particles
can exist, which are not visible by XRD because of the limit of
detection. However, the concentration of the hydrogen
species related to the band at 870 cm-1 decreases when the
Ni loading is decreased, and it disappears when the Ni/Ce
ratio is 0.5:1 (Figure 7), which is in agreement with the
existence of a high proportion of solid solution of cerium and
nickel in this compound.[8a]
ð7Þ
O
2ꢀMnþ& þ C2H5OH ! OHꢀMnþHꢀ þ C2H4O
Such a site has already been modeled, as shown in
Scheme 1, by an ensemble of two cations in close interaction.
Three coordinatively unsaturated sites (3 CUS, 3M) are a
Figure 7. INS spectrum of CeNi0.5HZOY treated in H2 at 2508C after
subtraction of the CeNi0.5OY spectrum.
Scheme 1. Mechanism and active-site modeling for ethanol transfor-
mation over CeNiHZOY nano-oxyhydride. (Nin+: Ni2+ or Nid+ and Cen’+
:
Ce4+ or Ce3+
)
The same phenomenon (exothermicity) is observed in the
absence of hydrogen species corresponding to the band at
870 cmꢀ1. When the oxyhydride is re-oxidized at ambient
temperature in air, the reaction is exothermic and the peak
related to hydride species disappears, whereas an intense
large band at 630 cmꢀ1 appears, which is assigned to the
formation of hydroxy groups (Figure 6). This finding is in
good agreement with the existence of highly reactive hydride
species leading in the presence of O2 to the formation of
hydroxy groups [Reaction (6)]. When the solid is pumped
several times, these hydroxy groups can be eliminated (water)
and the spectrum obtained is the same as the one observed for
the calcined CeNiOY solid.
prerequisite for alkadiene hydrogenation activity, and differ-
X
Y
ꢀ
ent ensembles
M
M’ (where X and Y are the numbers of
unsaturations (anionic vacancies) on each cation) have been
proposed to be the active sites, each elementary ensemble
being associated with a particular reaction.[8b,c] Depending on
the unsaturation degree of this active site, conversion of
3
ethanol can lead to different products. In Scheme 1 the Ni–
1Ce site leads to the formation of H2, CO, and CH4. At a
lower number of anionic vacancies on the site, acetaldehyde
and H2 can be obtained by heterolytic abstraction of hydro-
3
ꢀ
gen. At a higher number of anionic vacancies on the site ( Ni
3Ce) obtained after treatment with H2 at 2508C, ethanol can
be converted to H2, CO, and carbon. As a matter of fact, H2
production from CH4 has been proposed for this kind of
catalyst.[8d] This finding is in agreement with the observed
increase of O vacancies induced by doping ceria with Ni[4a,8a,12]
even if the existence of a hydride species has not been
envisaged.[4a]
Hꢀ þ 1=2 O2 ! OHꢀ
ð6Þ
The ethanol dehydrogenation step requires the abstrac-
tion of hydrogen species from an alcohol, which is the rate-
determining step. Therefore, the ability of the solid to accept
hydrogen is an important factor. The measured variation of
temperature can be mainly attributed to the reaction between
hydride species of the solid with O2 (exothermic) and the
variation of temperature depends on the concentration of
hydrogen stored in the solid in the form of hydrides. This
phenomenon allows the decrease of the oven temperature. A
part of hydride species formed from ethanol react with O2,
providing chemical energy, which maintains the catalytic
reaction. The reaction is sustainable because hydride species
are replaced and provided by ethanol. Finally, as it has been
In conclusion, we have successfully developed a new route
for hydrogen production that saves energy by smartly
combining chemical reactions which take advantage of the
reactivity of hydride species stored in active CeNiHZOY nano-
oxyhydride catalysts. We believe that our discoveries may be
general and can be applied to many other processes. Our
findings will motivate further fundamental theoretical and
experimental studies and will lead to new exciting develop-
ments.
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Angew. Chem. Int. Ed. 2011, 50, 10193 –10197

Experimental Section
[1] a) V. A. Goltsov, T. N. Veziroglu, L. F. Goltsova, Int. J. Hydrogen
Energy 2006, 31, 153 – 159; b) A. Midilli, M. Ay, I. Dincer, M. A.
Rosen, Renewable Sustainable Energy Rev. 2005, 9, 273 – 287.
[2] a) A. Haryanto, S. Fernando, N. Murali, S. Adhikari, Energy
Fuels 2005, 19, 2098 – 2106; b) M. Ni, D. Y. C. Leung, M. K. H.
Leung, Int. J. Hydrogen Energy 2007, 32, 3238 – 3247.
[3] a) A. Kowal, M. Li, M. Shao, K. Sasaki, M. B. Vukmirovic, J.
Zhang, N. S. Marinkovic, P. Liu, A. I. Frenkel, R. R. Adzic, Nat.
Mater. 2009, 8, 325 – 330; b) F. Frusteri, S. Freni, V. Chiodo, S.
Donato, G. Bonura, S. Cavallaro, Int. J. Hydrogen Energy 2006,
31, 15, 2193 – 2199; c) C. Resini, M. C. H. Delgado, S. Presto,
L. J. Alemany, P. Riani, R. Marazza, G. Ramis, G. Busca, Int. J.
Hydrogen Energy 2008, 33, 3728 – 3735; d) C. Lamy, S. Rous-
seau, E. M. Belgsir, C. Coutanceau, J.-M. Leger, Electrochim.
Acta 2004, 49, 3901 – 3908; e) E. Antolini, J. Power Sources 2007,
170, 1 – 12.
[4] a) G. Zhou, L. Barrio, S. Agnoli, S. D. Senanayake, J. Evans, A.
Kubacka, M. Estrella, J. C. Hanson, A. Martꢀnez-Arias, M.
Fernꢁndez-Garcꢀa, J. A. Rodriguez, Angew. Chem. 2010, 122,
9874 – 9878; Angew. Chem. Int. Ed. 2010, 49, 9680 – 9684; b) C.
Resini, T. Montanari, L. Barattini, G. Ramis, G. Busca, S. Presto,
P. Riani, R. Marazza, M. Sisani, F. Marmottini, U. Costantino,
Appl. Catal. A 2009, 355, 83 – 93.
The CeNiOY nanocompound was prepared by coprecipitation of the
corresponding hydroxides from mixtures of cerium and nickel nitrates
(0.5m) using triethylamine as a precipitating agent. After filtration,
the solid was dried at 1008C and calcined in air at 5008C for 4 h. The
loading was measured by microanalysis and the specific surface area
(SA) by the Brunauer–Emmett–Teller (BET) method (Table 1).
XRD analysis was carried out with a D 5000 Siemens diffrac-
tometer. The crystallites size was calculated, using the Halder–
Vagner–Langford equation, from the most intense reflections
observed for the NiO and CeO2 crystallographic structures.
TPR was performed on a Micromeritics Autochem 2920 analyzer,
and the hydrogen consumption was measured using a thermal
conductivity detector (TCD): 0.05 g of the sample were treated in a
H2 (5%)/Ar (95%) gas mixture (2 Lhꢀ1). The temperature was
increased to 8008C at a heating rate of 108Cminꢀ1
.
Inelastic neutron scattering (INS) experiments were performed
using the IN1 BeF spectrometer at the Institut Laue Langevin,
Grenoble. The solid (36 g) was placed in a stainless steel container
and the treatment with H2 (10 h) was performed using gas of high
purity. INS experiments were carried out at 10 K using a Cu (200)
monochromator for energy transfers between 80 and 380 cmꢀ1 and a
Cu (220) monochromator for energy transfers between 380 and
3000 cmꢀ1. The scattering cross-section is much greater for hydrogen
(80 barns) than for other elements (5 barns), therefore, INS empha-
sizes motions of hydrogen species.
[5] a) J. R. Salge, G. A. Deluga, L. D. Schmidt, J. Catal. 2005, 235, 1,
69 – 78; b) S. N. Hsu, J. L. Bi, W. F. Wang, C. T. Yeh, C. B. Wang,
Int. J. Hydrogen Energy 2008, 33, 2, 693 – 699.
The catalytic performances were measured at atmospheric
pressure with a quartz fixed-bed reactor (inner diameter 4 mm)
fitted in a programmable oven, in the temperature range of 60–5008C.
The catalyst was previously treated in situ with H2 at 2508C for 10 h to
form the oxyhydride. The water/ethanol mixture (molar ratio 3:1) was
pumped and vaporized in a preheating chamber. The O2/ethanol
molar ratio was varied between 0.5:1 up to 2.5:1. The ethanol/water/
O2/N2 gas stream (total flow: 60 mLminꢀ1) was then fed to the reactor.
The catalyst (0.2 g) was diluted in SiC and sandwiched between four
layers of SiC. Almost the same effect has been obtained without
dilution. The gases at the outlet of the reactor were analyzed on-line
by gas chromatography using flame ionization (FID) and thermal
conductivity detectors. The reaction data were collected as a function
of time and reported after 5 h at each temperature. Solid carbon was
formed as reported.
The reactants must be introduced in a specific order and O2 must
be introduced at last to avoid re-oxidation of the oxyhydride. When
the reactants were introduced in the reactor, the reactor temperature
significantly varied, depending on the ability of the oxyhydride
catalyst to react with O2. Introducing the mixture of EtOH/H2O/O2
into the reactor at 2008C (or 2308C, 0.03 g) resulted in an increase in
temperature. The heating of the reactor was lowered as soon as the
catalytic reaction started and the variation of temperature was
measured.
[6] a) G. A. Deluga, J. R. Salge, L. D. Schmidt, X. E. Verykios,
Science 2004, 303, 993 – 997; b) S. Velu, N. Satoh, C. S. Gopinath,
K. Suzuki, Catal. Lett. 2002, 82, 1 – 2, 145 – 152; c) H. Chen, H.
Yu, F. Peng, H. Wang, J. Yang, M. Pan, J. Catal. 2010, 269, 281 –
290; d) O. Akdim, W. Cai, V. Fierro, H. Provendier, A. van Veen,
W. Shen, C. Mirodatos, Top. Catal. 2008, 51, 22 – 38; e) S. M.
De Lima, I. O. da Cruz, G. Jacobs, B. H. Davis, L. V. Mattos, F. B.
Noronha, J. Catal. 2008, 257, 356 – 368; f) J. Kugai, V. Subramani,
C. Song, M. H. Engelhard, Y. H. Chin, J. Catal. 2006, 238, 430 –
440; g) W. J. Cai, F. G. Wang, E. S. Zhan, A. C. Van Veen, C.
Mirodatos, W. J. Shen, J. Catal. 2008, 257, 96 – 107.
[7] a) L. Jalowiecki-Duhamel, C. Pirez, M. Capron, F. Dumeignil, E.
Payen, Int. J. Hydrogen Energy 2010, 35, 12741 – 12750; b) L.
Jalowiecki-Duhamel, C. Pirez, M. Capron, F. Dumeignil, E.
Payen, Catal. Today 2010, 157, 456 – 461.
[8] a) C. Lamonier, A. Ponchel, A. D’Huysser, L. Jalowiecki-
Duhamel, Catal. Today 1999, 50, 247 – 259; b) L. Jalowiecki-
Duhamel, Int. J. Hydrogen Energy 2006, 31, 191 – 195; c) L.
Jalowiecki-Duhamel, J. Carpentier, A. Ponchel, Int. J. Hydrogen
Energy 2007, 32, 2439 – 2444; d) L Jalowiecki-Duhamel, H.
Zarrou, A. D’Huysser, Int. J. Hydrogen Energy 2008, 33, 5527 –
5534.
[9] S. Kacimi, D. Duprez, J. A. Dalmon, J. Chim. Phys. Biol. 1997,
94, 535 – 552.
[10] H. Jobic, Handbook of Heterogeneous Catalysis, 2nd ed. (Eds. G.
Ertl, H. Knçzinger, F. Schꢂth, J. Weitkamp), Wiley-VCH 2008,
971.
[11] L. Jalowiecki-Duhamel, S. Debeusscher, H. Jobic, E. Payen, Int.
J. Nuclear Hydrogen Production and Applications 2009, 2, 148 –
158.
Received: April 15, 2011
Revised: July 14, 2011
Published online: August 24, 2011
[12] L. Barrio, A. Kubacka, G. Zhou, M. Estrella, A. Martinez-Arias,
J. C. Hanson, M. Fernꢁndez-Garcia, J. A. Rodriguez, J. Phys.
Chem. C 2010, 114, 12689 – 12697.
Keywords: ethanol · heterogeneous catalysis · hydrogen ·
metal oxides · sustainable chemistry
.
Angew. Chem. Int. Ed. 2011, 50, 10193 –10197
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org 10197