Aula com Exemplos de Aplicações. Disciplina EMC5732 - Estrutura Cristalina de Solidos (/ Caracterização de Materiais 2), 2011/03, Prof. Ana Maria Maliska Curso - Engenharia de Materiais Departamento de Engenharia Mecânica Universidade Federal de Santa Catarina

1. Estrutural Cristalina de Sólidos:
Aplicações
Prof. Ana Maliska
Daphiny Po?maier, posdoc
21‐set‐2011.

2. Nucleação e cristalização da SiO2
S A X S and D LS study of silica nanoparticle formation 5385
F ig. 5. ( A ) T ime evolution of the normalized scattering intensity, a r , in solutions with 640 and 1600 ppm Si O 2 at two di ere
P(R) of scattered silica nanoparticles as a function of R and time (t = 10–55 min with time steps of 5 min) evaluated with G N O
(1600 ppm Si O 2, IS = 0.05).
( A ) F E G –SE M and (B) T E M photomicrograph of silica nanoparticles grown for 30 min in a solution with 1600 ppm Si O 2 and IS of
) C ryo-T E M photomicrograph of silica nanoparticles quenched after 1.5 h from a solution with 1600 ppm Si O 2 and IS of 0.05.
ison of particle diameters obtained from S A X S, D LS and T E M .
pm) IS T ime (h) Particle diameter (nm)
S A X Sa D LS TEM
0.02 1 5.8 4.6 ± 1.0 3.1 ± 0.4
2 6.7 4.7 ± 1.1 3.3 ± 0.4
0.11 1 7.0 — —
2 7.7 — 4.5 ± 0.7
0.22 1 7.2 5.8 ± 1.9 5.2 ± 0.9
2 8.0 8.0 ± 5.0 3.6 ± 0.5
0.05 1 6.9 8.7 ± 2.2 —
1.5 7.2b 10.1 ± 3.1 6.1 ± 1.1c
b
2 7.5 9.6 ± 1.8 —
0.11 1 7.6 9.9 ± 3.5 5.4 ± 0.5
2 7.9 A ggregation —
0.22 0.5 G rowth of silica nanoparticles in solutions with varying [Si O ] and 5.1 as0.6
F ig. 6. 7.5 8.0 ± 1.0 IS ± determined by D LS. T he arrow indicates the
2
D.J. Tobler, S.Shaw , L.G. Benning “QuanTficaTon of iniTal steps of nucleaTon and growth of silica nanoparTcles: An in‐situ SAXS and
1 7.9 A ggregation 6.7 ± 0.9
aggregation for solutions with 1600 ppm Si O 2 and IS of 0.22 (% errors are average values).
DLS study” Geochimica et Cosmochimica Acta 73 (2009) 5377–5393A ggregation
2 7.9 —
r of S A X S <3%.

3. g the next best
monds, is not the only element that is
to hardness. Boron and nitrogen also high pressure and temperature, but theThey areat the hardest natural form of carbon
beauty. first the ESRF as the densest material
A procura da melhor coisa depois dos
trong, short chemical bonds. In 1956 experiments failed. The scientists soonand are highly valued by industry for
known noticed (Dubrovinskaia et al. 2005).
sts combined boron and nitrogen to that there was a small portion of the structure Results showed that the A DNRs’ density is
after diamonds
cubic boron nitride (cBN), which has
this property. Industrial uses include cutting,
that was already surprisingly super-hard at greater than that of diamond by 0.2–0.4%
used as an alternative for synthetic drilling, grindingand is 11% less compressible. The combination
ambient conditions. The team then decided and polishing. However,
ess of diamond. Diamantes
nds. However, it only has half of the
am from the Institute for Superhard
to isolate the small particle, compress it andfew draw backs: diamonds strongly
characterise it.
there are a of the hardness of the A DNRs and its chemical
stability could make it a potential material
resist heating and as soon as they are in
The results proved that, in accordance for machining hard materials, grinding
ISTO CKPH OTO.CO M
ials in Ukraine, together with scientists with previous theoretical predictions, contact with a metal, they allywell as for use asis
and polishing, as with it. This anvils in
he University of Paris, the University of why researchers scientificpursuitlike diamond anvil cells and
crystalline carbon nitrides exhibit exceptional are in devices of substitutes
uth (G ermany) and the ESRF, managed multi-anvil presses.
compressibility behaviour. In for diamonds with a better conductivity and
addition,
mbine carbon, boron and nitrogen in despite the usual considerations, the team A nother new material that is attracting
aterial in 2001. The result, cubic BC 2 N, demonstrated that there is no need more for severe to temperature andthe super-hard
resistance the interest of industry is corrosion.
mpound that is half way bet ween and expensive pressure and temperature To create new aggregated boron nitride nanocomposite
materials, scientists focus
nd and boron nitride in composition. on the periodic table. C), synthesised by the same team and
conditions to elaborate low-compressibility, (ABNN Carbon, the source Ap
am applied a pressure of 18 GPa covalent materials (Goglio et al. 2009). tested at the Swiss Norwegian Beamline at
mperatures above 2200 K, w hich
of diamonds, is not ESRF (Dubrovinskaia et that is ABNN C
The dow nside of this story, and most of the the
the only element al. 2007).
red the appearance of a ne w phase. stories linked to creating new materials, hardness. Boron and nitrogen bulk material hig
linked to is that is the first non-carbon-based also
ugh the ne w compound is not as hard their production is still at a very small scale. short chemical hardness approaching that exp
form strong, with a value of bonds. In 1956
mond, it is harder than its predecessor, In most cases, w hen scientists try to increase of single crystal and polycrystalline diamond
scientists combined boron and nitrogen to tha
Despite the fact that it was synthesised the production, the material decomposes, and A DNRs. ABNN C also has unusually high
years ago, its usepaper on diamond ishighly in and w hich means that the phases are verycubic boron nitride (cBN), which resistance, as tha
Apart from
the in jewellery, BC 2 N is still valued widely used in industry. create fragile. fracture toughness and wear has
melight (Solozhenko et al. 2001). Proof However, the creation of new hard materials an well as high thermal stability (above 1600 K in
been used as alternative for synthetic am
are the 150 and temperature, butit has had(Dubrovinskaia et densest form of carbon and researchers
high pressure citations that the first at the ESRFis progressing swiftly
– as the air), making it an exceptional the
diamonds. However, it only has half of superabrasive. to i
experiments failed. The scientists soon noticed al. 2005).
w hichthere wasinsmall portion of the structure
that were a 2008. Results showed that the A DNRs’ density is it is only a question of
generally comment that M Capellas
that was already surprisingly super-hard at hardness of in
time until new materials can be synthesised
greater than that of diamond by 0.2–0.4% diamond. cha
ambient conditions. The team then decided
ap,to isolate the small particle, compress it and
super-hard material
and is 11% less compressible. The combination
large quantities.
of the hardness of the A DNRs and its chemical A team from the Institute for Superhard
References T
nancial cost of
characterise it. developing these new stability could make it a potential material
The results proved that, in accordance for machining hard materials, grinding M aterials in Ukraine, together with scientists Lett.wit
N Dubrovinskaia et al. 2005 Appl. Phys.
alswith a mass-production rate will and polishing, as well as forinterest in
at previous theoretical predictions, Industrial use as anvils 87 083106.
mine whether they will be used in
crystalline carbon nitrides exhibit exceptional anvil University of Bayreuth University of Paris, the University of Lett.
scientific devices like diamond the cells and
A team from
from the N Dubrovinskaia et al. 2007 Appl. Phys.
cry
ry. despite the usual considerations, the team for an A notherhas material that is attracting to raiseBayreuth (G ermany) and the ESRF, managed com
compressibility behaviour. In addition, multi-anvil presses.
A potentially cheap solution new already managed the interest 90 101912.
demonstratedis the result of research the interestof industry is the super-hard
ard material that there is no need for severe
and expensive pressure and temperature
to combine carbon, boron and nitrogen in
of industry in their patented Aggregated
aggregated boron nitride nanocomposite
G Goglio et al. 2009 Diamond & Related des
by the University oflow-compressibility, the
conditions to elaborate Bordeaux and (ABNN C), synthesised by the same team andDNRs), a new material in 2001. The 627–631.cubic BC N,
Diamond Nanorods (A
one material Materials 18
result, dem
synthesised in 2005 based on bulk samples
sity of Clermont-Ferrand (France). tested at the Swiss Norwegian Beamline at
covalent materials (Goglio et al. 2009). 2
V L Solozhenko et al. 2001 Appl. Phys. Lett.
The dow nside of this story, and most of the the ESRF (Dubrovinskaia et al. 2007). ABNN C
of nanocrystalline diamond and identified
team studied creating new materials, is that is the first non-carbon-based bulk material
stories linked to a carbon nitride under
is a compound that is half way bet ween
78 1385–1387. and
their production is still at a very small scale. with a value of hardness approaching that diamond and boron nitride in composition. con

4. tor, and vice versa
splacements leading to the new
etallisation takes place due to
ygen, are insulating at room temperature, but if you put them
f the band gap that occurs with
to conducto
O2, Na e Li, Isolante‐Condutor? oxygen
of the that don’t have electrical resistance. The other way
erials lattice, which evolves into
cture withtakes place with of
ic event, the dissociation elements such as lithium or sodium.
ing to
c oxygen can transform even Many elements, such as
tities. understand why and how these events happen.
under pressure you get materia
e 250 GPa, theoreticians predict
L LUNDEG A ARD
ons to an atomic metal. “This is
enge for ID27, providing that the
,
o
round, which is a more exotic e
ood quality single crystals at these Composite diffraction image: data from the one of the phases of sodium with 90 atoms in unit cell.
ut
explains Mohamed Mezouar, the
Scientists are slowly managing
t
arge of the beamline. phases are reached in a very small region of
“Sodium
pressure–temperature domain, in the vicinity
s of the sodium’s melting curve minimum.
meffect from oxygen under Slight changes in pressure or temperature set
y
s place when metals, such as and lithium Oxygen is the third most abundant which are very
off new transitions, some of element
thium, become compressed. in the universe by mass,had never been observed in any
complex and after hydrogen and
long to the group of lighter
wsified as “simple metals”,
are actually other element before. One of these structures
helium. More than 20% than 500 atoms in the air cell.
contains more
of the volume of unit
they have simple crystal and
uctures. However, under
o
insulating when consists of oxygen. Despite its predominance,on
The team carried out their experiments
its behaviourID27 using single-crystal diffraction. They
under pressure is still not clear to
adopt different physical states.
o separate teams (Ma et al. under pressure” identified the lattice parameters and the
researchers. Above of pressure of 96phases. The
a
number atoms of all seven
GPa (about
a quarter of the pressure inside light on theoretical
results for sodium shed the Earth’s
t
tsuoka et al. 2009) discovered
and lithium are actually
e under ordinary conditions sodium adoptsoxygen has shown a metallic phase,other
core), a models that predict bizarre states for but
se Composite diffraction image: data from the one of the phases of sodium with 90 atoms in unit cell.
en under pressure and that straightforward crystal structure, but under materials, such as hydrogen.
Na ‐ 7 fases! ‐ pressao/temperaturasmall region of highscientists have only recently determined the
e
mes transparent, using Raman phases are reached in a very therefore
high pressure, and density M Capellas
“Sodium
y and the Advanced Photon
pressure–temperature domain, in the vicinity
of the metal, things change. For starters,
of the sodium’s melting curve minimum.
changes in its crystalline structure.
cago (US) (Ma et al. 2009). the melting temperature of sodium is lower from the Commissariat à l’Energie
Slight changes in pressure or temperature set
A team References
and lithium on
ering experimental work
off new transitions, some of which are very
complex andpressure (118 GPa) any E Gregoryanz et al. 2008 Science 320 1054.
at high had never been observed in than atAtomique (France), the University of O ttawa
ambient
are actually
odium under high pressure other element before. One of these structures
contains more thanToday, a team from the University
conditions. 500 atoms in the unit cell. Y Ma et al. 2009 Nature 458 182–185.
(Canada) and the ESRF, clarified a standing
insulating when ID27 Edinburgh (Gregoryanz et
t the ESRF on the beamline ofThe team carried out their experiments on al. 2008) and T Matsuoka et al. 2009 Nature 458 186–189.
years ago. It was known that
using single-crystal diffraction. They
debate on the Weck et al. 2009the 102 255503.
identified the lattice parameters seven different crystalline
the ESRF found that and the G transition of PRL element from
.
under pressure” number of atoms of all seven phases. The

5. Focus on: extreme conditions
rthCondições Extremas – centro da terra
to its surface from the centre
Take a trip
The Earth is still an enigma.
The Earth’s layers
N ASA G O DDARD SPA CE FLIG HT CENTER (N ASA- GSF C)
But the ESRF is helping to
Layer Distance from surface (km) Pressure (GPa)
Crust 0–35 <1
demystify our Temperature (ºC)
planet, its
200–600
Upper mantle 35–660 composition and inner activity.
1–25 600–1600
Lower mantle 660–2890 25–136 1600–4000
Outer core 2890–5150 136–330 believe that4400–6100 by
Geologists Earth was struck
a planet the size of Mars about 4.5 billion
Inner core 5150–6360 330–360 The impact 6100K (±500K)
years ago. led to the formation
of our satellite, the M oon and melted most
of the planet’s rocks, creating its core, as
the metallic iron bet ween the rocks sank
subsequently infer what the conditions must and anisotropy of magnesium- and iron-
towards the centre. Therefore, iron is of major
Fe (35%) + Ni + S, Si, C, O
be deep in the Earth.
At the ESRF, a team from the Institut de
containing silicate perovskites on ID24 and
interest in the scientific community. Despite
ID27. It also investigated post-perovskite
it being physically impossible to access the
Minéralogie et de Physique des Milieux of the Earth’s core, high-pressure experiments at
same material, which occurs when
synchrotron sources can provide major clues
Condensés at the University of Paris studied pressure increases in the and other materials
lower mantle. The
the sound velocity in solid iron alloyed with Fe‐FeS = Fe3S (1000 K)
about the role that iron
idea was to the core.
play in determine whether the phase
light elements using high-resolution inelastic transitions in perovskite are at the origin
The Earth’s core is divided into t wo zones:
the outer core, which is liquid, and the inner
X-ray scattering on ID28 (Badro et al. 2007). It of seismic discontinuities in the zone. The
core, which is solid. The main component of
ruled out sulphur as a possible light element
in the core and proposed that the inner core
Fel ‐ 2.8%Si + 5.3%O2
post-perovskite transition could alsothe
the core is iron, which is crystallised in provide
information about the know this because the
inner core. Scientists temperature variations
is made of iron, silicon (2.3% w t) and traces of the speed of sound the time of ESRFnews going
D’’ layer. At through the core (the velocity
at which seismic waves travel across it) and the
of oxygen. If extrapolated to the liquid state, to press, a very promising paperthose seen in
density of the core are similar to
addressing
the team suggests that the outer core could these questionspressures the temperatures. On
iron at high was in and submission process
silicate‐perovskites ‐> post‐perovskites
contain 2.8% w t silicon and 5.3% w t oxygen.
Silicon and oxygen can be partly dissolved in
(A ndraultof that, iron is sufficiently abundant in the
top et al. 2009).
It is crucial to make upperovskites with iron,
universe
to study for approximately 35% of
the mass of the planet present in the core.
iron, so the total amount of light elements in even if itHowever, iron is not alone in the core. The
is technically more complicated,
the inner core would be 2.5% w t, and 8% w t because iron is a transition element that can
core should contain ~10 % w t of nickel and,
in the outer core. change its importantly, seismology shows that
more electronic structure under pressure
both parts of the core are too light to be pure,
M ore recently, the team studied silicon and, as a consequence, the way that could
dense iron–nickel alloy. The outer core
the
bearing iron–nickel alloys and compared them Earth’s interior% w t of lighter elements, while
have 6–10 behaves. Researchers from
with pure iron. The results, which have been the UniversitycoreBayreuth carried outThe
the inner of would contain 2–3% w t. nuclear
submitted for publication, show a model for resonance experimentspotentially mix with iron
candidates that could
on ID18 and ID27,
are sulphur, silicon, carbon and oxygen.
the contribution of silicon and nickel to the as well as at the Advanced Photon Source,
Earth’s inner core. on lower-mantle perovskites. The goal was
The case of sulphur
to measure the spin-state transitionsthe iron
It is quite likely that sulphur is present in of
deepest sector of the Earth because meteorites
On the boundaries between the core and in the perovskite. Surprisingly, they found a
contain this element abundantly. A team from
the mantle: the weird D’’ layer stable the University of Paris and the University of the
intermediate spin state throughout
The core still has many surprises in store, lower mantle (McCammoniset al. 2008).
Clermont-Ferrand (France) studying how

6. histication. The researchers
ut have never clearly their work will Research light on
Scientific and shed
ied histone-binding of
d their role. Now, an
nal team of scientists
potential problems in sperm
Organization, the University of
California (US), the University
Proteína ligada à evolução do esperma,
,that there maythat it binds most
finding be a
reason for the presence
ngly on goldhistone with t wo
to a grain
developmentOntario and the
of Western and are now looking
University of Saskatchewan
at the (both Canada), this protein plays in
role that Martin-Luther-
acteria
olecular crystallography unveils (US), SCK.
bacteria para formar ouro
of thatparticular kind (in this
a the metal-
“A number of years ago
ered
human Nebraska-Lincoln University
male infertility.
Universität (Germany),
of
nked groups) and, image of1aµm metalliduranssperm the APS (US) and
, acetyl to the evolution of CEN (Belgium),
acterium
durans occurred on gold A TEM
contrary
C. the ESRF (France).
xpectations, usesultrathinone containingReference the first direct evidence
m t wo sites in Australia. just section a This is
place on ID23-1 and ID23-2.
ISTO CKPH OTO.CO M
einSouth Wales and dogold nanoparticle (in the middle).orinièrefewto a arerare and precious
domain to
re 3500 km apart, in
y.
New
so. J“smallcould only obtaincycling of actively involved
We
M in Brdtbacteria al. 2009 Nature 461
that a
crystals of
thebound
et
664–668. at the
he key experiments took which pushes the Petosa, metals, such as gold. These results
doubly tagged ligand,” explains
Queensland, so when gold toxicity, Carlo researcher
the same organism on bacterium to induce oxidative open the door to the production
Institut de Biologie Structurale
in Grenoble and member of the
m both sites we thought
s stress and metal resistance team. “ W hat’s more, the crystals “The discovery of a
of biosensors:
ere onto something. clusters as well as an as yet initially appeared to be unusable operon means that
gold-specific
because they were highly
wonder why these uncharacterised gold-specific we can now start to develop gold-
ESRF gets good ofHowever,to
Bacterium helps to fo
m disordered internally.
s live in this particular gene cluster in order to defend specific biosensors, which will help
exposing the edges a crystal
ent. The results of this marks from studyX-rays explorers to find new gold
a grazing beam of
its cellular integrity. This leads to thinnest tips gave a mineral revealed
that the Society
The American Physical It i
Australian scientists have found
nt to their involvement active biochemically mediated well-ordered deposits. To achieve this we need
REITH ET AL, PN AS 5–9 O CTOBER 2009
diffraction that the bacterium Cupriavidus
has recently completed the study pattern. te
July 2010 for reconstruction improvements facilitate the
ve detoxification of gold reduction of gold complexes to Internationalfurther characterise the gold-
nano-particulate, metallic data
“Access to Major to
Using the microfocused beam at
metallidurans catalyses the
X-ray and Neutron Scattering collect biomineralisation of gold
ID23-2, we could enough
s leading(the only cell in our body that swims) racing to get to the egg. gold,from a single crystaloperon on a genomic as
specific to solve
th
Sperm to formation
to
the same port. The renewed
ominerals”, explains alignment of the sample and the Facilities”, which explores by transforming toxic gold
which may contribute to thetheaccess to light as proteomic level. If funding
how scientists’ structure.” well compounds to their metallic form
of
su
that act code to direct
of the research nuggets. sources has been believe that active cellular mechanism.
The researchers
h, leader as achromatin structure. grow th of gold extra levelneutron their work willfor this research is granted I believe
the discovery of an and of using
24 will comprise t wo stations,
changes in
eng at the University to the
Different proteins bind of A FM-tip with respect to the X-ray
sophistication. The researchers not only in the US but light onResearchers reported the
evolving shed
studied histone-binding of internationally. The final in sperm produce a on gold
For this study scientists potential problems we presence of bacteria functioning
also that can
sc
Ad
hich will be commissioned beam. It enables the accurate
Brdt, finding that it binds report
most development and are now looking
tags, the combination of which combined synchrotron has been posted onbiosensor within have never clearly surfaces but 3–5 years,”
Australia). the code. Until now,
deciphers strongly to a histone withthe APS website at role w.aps. protein plays in their role. Now, an
t wo at the w w that this
Sc
elucidated Or
eriments showed these
scientists thought that tags of a particular kind (in this
org/programs/international/
concludes Reith.
techniques at the ESRF and human male infertility. international team of scientists
2011. Current planning is positioning of a pre-chosen
Ca
tallidurans rapidly or more the Advanced Photon Source
proteins bind using one case, acetyl groups) and, resources/facilities.cfm. It
contrary has found that there may be a of
e modular “domains”, with each to expectations, uses justpositions theReference leader in
one ESRF as the Un
tes toxic gold complexes (APS), and molecular microbialorinière etReference 461 reason on goldpresence biological for the
reopen the first branch of
domain docking to just one tag.
nanostructure in the focal beam
protein domain to do so. synchrotron J M
ution prepared in reports techniques to understand the
However, this new study The key experiments took decade.
facilities for the next Nature bacteria
al. 2009 of these
664–668. F Reith et al. 2009 PN AS.
grain
surfaces. “A number of years ago
(b
Un
e renewed beamline in the user groupsspot that can currently be as small
his process promotes biomineralisation in bacteria. 32 facilities and
across the globe
For the study,
resistant bacterium
doi:10.1073/pnas.0904583106.
we discovered that the metal-
1 µm
of
CE

7. of Kiel (Germany) and the stable, to room temperature.
found a rapid synthesis of an Because the researchers discovered that
his well studied material.
2 O 8 had been thought to be
Síntese de Materiais “NTE” this NTE material can be synthesised in this
way, it means that lengthy precursor routes
ght: viewed from the three fold axis. ZrO6 octahedra is shown in green, careful thermal transformations may
all temperatures and, unlike requiring MoO4 tetrahedra inon: time-resolved studies
Focus yellow.
it had not been possible to no longer be necessary.
follow the synthesis
rectly from the constituent
ow.
John Evans, leader of the team, from
Durham University, comments that
material as it happens
hers noticed in their lab that “the use of extremely rapid quantitative
able to form the supposedly powder diffraction at the ESRF was crucial
bic phase by firing the to unravelling this chemistry and similar
at NTE materials expand anisotropically, thetechniques could X-rays of the significant insight in
desM osthigh temperatures high flux and high-energy provide
few secondscubic crystal structure the beamline, areas of materials synthesis”.
othera unique real-time insight into the
followed by rapid them with and the FRELO N camera provided
(differently in all dimensions). However, for
materials with a
M Capellas
e team used the ID11 beamlineall synthesis of the new material. This camera was
symmetry forces them to contract equally in
situ minimise – isotropicsuch as micro-cracking short timescales over which the different
dimensions
to
experiments contraction. This helps particularly important due to the extremely
problems
to monitor the
Two
as cycling. Reference
e metal oxides views of ZrMo O from different angles. Right: viewed from the three fold axis. ZrO octahedra is shown in green, MoO tetrahedra in yellow.
during repeated thermalthey reacted phases appeared.
The most famous cubic NTE material The reaction took place extremely quickly
2 8 6 4
atures, using the(ZrW 2 O 8), which
is zirconium tungstate technique at elevated temperatures with ZrM o 2 O 8 J. Am. Chem. Soc.
J E Readman et al. 2009
Scientists follow the synthesis
raction. They benefited from
contracts over a temperature range of
0.3–1050 K. However, at about 450 K, it
doi:10.1021/ja907648z.
formation occurring within seconds at
~1360–1400 K. Reaction occurs via the
of an NTE material as it happens
suffers a transition from an ordered structure
to a disordered one, and above 0.2 GPa of
melting of M o O 3 , the formation of trigonal
ZrM o 2 O 8 and then the formation of cubic
pressure it becomes significantly denser and
A team of European
loses NTE properties. These transitions could
ZrM o 2 O 8 . The reaction is complete within
a few NTEinmaterialsand the material can be flux and high-energy X-rays of the
M ost seconds expand anisotropically,
(differently all dimensions). However, for
the high
beamline, and the FRELO N camera provided
9
limit the industrial uses for this material. has,
scientists and the ESRF quenchedafromcrystal structure the conditions, a unique real-time insight into the
materials with cubic the reaction them with
Researchers from Durham University (UK), where it –appears contract thermodynamically new material.the extremelywas
symmetry forces them to to be equally in all synthesis of the This camera
for the first time, enabled dimensions isotropic contraction. This helps particularly important due to

8. Células Combusoveis Poliméricas
A Mercedes Benz Citaro London bus running on fuel cells. This kind of bus was first used in 2004
in the English capital. Several cities around the world already use fuel cells in their buses.
Take a look inside a fuel cell
solid polymer distributor The fuel cell uses hydrogen and oxygen to
electrolyte plate create electricity. The reaction occurs in
H2 a structure consisting of two electrodes
cathode (the anode and the cathode) separated by
anode the electrolyte membrane, which lets the
ions through. The electrodes activate the
H+ hydrogen oxidation as well as the oxygen
O2 (air)
reduction.
– current In the case of a proton-exchange
collector
study, one can conclude that this membrane, the hydrogen at the anode is
C O M M U N IC ATI O N
H 2O MEA dissociated into protons and electrons. At the
he correlation between evenelectricity
+ minimal
cathode, the oxygen, electrons and protons
the hydration degree, as can heatseen in
be recombine to form water.
red circles in Figure 3.
study consisted of a vertical scan of the
through an external circuit, and in this way
executed collecting the diffraction thickness. The researchers took a sequence
provide the electric power. To effectively of diffraction patterns that showed the water
primary X-ray beam with a transversal be changes induced by changes of the working
transport protons, the membrane needs to
100 mm (horizontal).
humidified. However, an excess of water may conditions. In this way, the variations in the
eady conditions (after about the consequent degree of water could be correlated with the
produce cathode flooding and 2 h, at the
of decreaseA), the cell performances. accom-
100 m of stratigraphy was cell voltage.
Several groups are studying membranes The team also carried out spacially
position at which the primary beam resolved experiments to determine the water
like Nafion at the ESRF to monitor in situ
rface changes that itcatalyst at the anode
the with the Pt goes through during the distribution along the membrane thickness.
vely vertically shifted, in steps of the aging
oxidation and reduction processes, 7 mm, This helped the scientists to elucidate in
atof its nanostructure, or its hydration degree
the cathode side was reached, with detail the complex water dynamics occurring
as a function of the operative electrochemical in the active component of a running fuel
on at each step. Since the membrane
parameters. The scientists use beamlines such cell. Valerio Rossi Albertini, a member of the
chas ID02, ID13, ID15 andthe water content
sampling allowed BM26. team, explains that: “the water dynamics
k of Recently, a team from the Istituto di
21 different ‘‘slices’’. The main in the membrane of a fuel cell is one of the
patterns of theMateria in Rome, University
Struttura della collected sequence are main aspects in the use of such devices for
˚ 1 (see the insert of Fig.
of Camerino (Italy), and the ESRF measured
ues 0.5 and 5 A locomotion. The variable working conditions,
the water in a running fuel-cell membrane for instance because of the request of
membrane layer by layer from the H 2
in real-life conditions. For this experiment, rapid increase of power supply during the
lectrode, the trend can be qualitatively
they used the high-energy beamline ID15B acceleration of a vehicle, may produce
heand determined the overall presence of water
initial patterns of the sequence, dysfunctions and electrochemical instabilities
C. C. de Araujo, K. D. Kreuer, M. Schuster, G. Portale, H. Mendil‐Jakani, G. Gebel and J. Maier ”Poly(p‐phenylene sulfone)s with high ion exchange
and the hydration degree the H layer of the Figureto water overproduction. Conversely, an distribution in the PEM in
the membrane close to in each 2 anode, due 4. Space-resolved study of the water
steady conditions: water the supplyingthe membrane as a function of the
insufficient hydration of content of gases
capacity: ionomers with unique microstructural and transport features” Phys. Chem. Chem. Phys., 2009, 11, 3305‐3312.
membrane with the highest precision ever.
increase of the main-peak height (at
To observe the overall amount of water vertical scan,releaseanode to cathode,current
or the heat from due to the proton and reverse. The diffraction patterns
aindecrease of the team carried out the
the membrane, the intensity in corresponding to may two scanning sequences (from the H 2 to the O 2
in the membrane the result in its drying.
V. Rossi AlberTni, B. Paci, F.Nobili, R. Marassi, M. Di Michiel “Time/Space‐Resolved Studies of the Nafion Membrane HydraTon Profile in a
er the experiment by irradiatingthe trend is
the first five patterns, a Nafion 117 electrode and developedare ID15 can help the insert.
The method reverse) at reported in in
Running Fuel Cell” Advanced Materials Volume 21, Issue 5, pages 578–583, February 2, 2009.
itymembrane, main 140 µm thick, with an X-ray understanding and describing such complex
of the about peak progressively
ope. The scanning sequence was to its
beam with a cross-section equivalent
then tion) dynamics.”(horizontal), which allowed the hydration degree
water
100 mm

9. structure before and after the “breathing” is produced by industry within a complex
process, using X-ray powder diffraction. mixture of CO 2 , CH 4 , CO, H 2S, CH 4 ..., one has
Armazenando gases e energia,
Today the team is working on the use of to capture CO 2 with a high selectivity versus
M OFs for their separation properties (gases, the other components. M OFs, with their
liquids) as well as to develop biomedical tunable pore size, large sorption capacities,
energy applications using non-toxic biodegradable good selectivity and easy regeneration, offer a
for a greener future
iron M OFs. nice alternative to zeolites or amines.
projetando as baterias de Li do futuro
ng gases: a key for a greener future
ore
Industrial applications on hydrogen
storage are already under way. Researchers
from the company BASF showed recently
that, compared with pressurising an empty
Experiments at the ESRF allowed the
team to study the breathing of the solid
upon adsorption. By combining diffraction
with Raman spectroscopy and computer
has
lop container with hydrogen, if the M OFs are simulations, they evaluated the “breathing”
gen added they increasingly take up higher pattern of the MILs. They found that the
he
ul tool amounts of hydrogen with less pressure. coadsorption of CO 2 and CH 4 leads to a
eld. to design and build different structures that similar breathing pattern of MIL-53 (Cr) as
ISTO CKPH OTO.CO M
INSTITUT L AVOISIER
ydrogen
could take up molecules of a different size. Sequestration of toxic gases with pure CO 2 .
nergy They have developed a variety of MILs (for
gen is
le, it
f any
CO 2 and CH 4 are t wo types of gases that For the future, scientists find potential in the
t does
Material Institut Lavoisier), including the are currently damaging our planet, so their flexibility of some MILs: “ One could imagine
ing the lithium-ion
ges, its
the
metal terephthalate MIL-101 back in 2005, elimination would be another step towards a benefiting from the flexibility by applying
ture
he
a structure with very large internal pores cleaner environment. CH 4 is not adsorbed by a mechanical pressure to make the MIL-53
gas
ot of (a diameter of 3.4 nm) and surface area M OFs as well as CO 2 , but, on the other hand, solid close its pores and desorb gas mixtures,
unity
es of the future
store
y by
(5900 m 2 g –1). This MIL is still studied today and both of these gases are adsorbed at room for an easier regeneration without the need
it into
tested for the purification of hydrogen using temperature, unlike hydrogen. for thermal or vacuum treatments,” explains
s to
uent
uture
mixtures of greenhouse gases (CO 2 and CH 4). A team led by the University of Aix- Christian Serre of the Institut Lavoisier.
M ore recently, together with ayears later, the team joined forces with
Two group at the A nother promising way of storing hydrogen,
r the gas hydrogen-release temperatures as well.
more
Metal-organic frameworks Left: hydrogen, a simple element that has given hopeCapellas
M arseille in collaboration with the team M to scientists in the quest for a more
tions.
be
University of A arhus (Denmark), they prepared as well as capturing gases such as CO , is the
the University ofOFs aremetal-organicto publish its results
and characterised novel anion-substituted
2
Rennes frameworks (M OF).
so-called
environmentallyLavoisier,world. Above: The MIL-53 is a very flexible metal-organic framework.
from the Institut friendly together with
ISTO CKPH OTO.CO M
IFP, the University of Caen, of the structure (large pore form); on the right, the structure
On the left, the dried form the University
ydrogen modifications of these materials. M extended crystalline net works
ds or
fied, and on new (BH ) by a frameworks:open pores
hybrid made of metal/oxide groups heldMIL-88 A , B, C
The joint team also prepared novel materials
by cation substitution, e.g. LiZn by organic linkers, with large,
together
References
(narrow pore form)the ESRF (all in France),
after adsorption of various guests,Arnbjerg et al. 2009 Chem. Mater. 21
L M such as carbon dioxide or water.
2 4 5
ms are reaction of LiBH and ZnCl . The idea was to that make them ideal for storing gases. Their
introduce a less electropositive metal (Zn) in the pore size and shape canthese new structures
and D. The peculiarity of of M ontpellier and
4 2
be easily tuned
certain structure of the borohydride. “ We discovered a by changing either the organic ligands or
on
new compounds,that they could sustain a reversible huge
is which store large amounts of have other applications, such as sensors in
much unexpected structural chemistry of these the metallic clusters. They can potentially
recently studied MIL-53 (Cr) for the 5772–5782.
without breaking bonds and retaining the It is necessary to separate the t wo gases
rogen
increasealreadyvolume. It these materialsprocesses. The 85% of
in in catalysis and ranged from separation of mixtures of CO 2 and CH 4 at T Devic et al. 2010 J. Am. Chem. Soc. 132
etrol, hydrogen and release it at low temperatures of nanotechnology, and they are already used
orage some 80–100 °C,” explains Yaroslav Filinchuk, ion-exchange
ee of BM1. He continues: “ We have advantages of in comparison
crystallinity of the materials. The reverse as part of the capture, transportation and
hydrides, show interesting structural, chemical and to an unprecedented 230% . Such
e
their size up density and the hydrogen storage is governed
proven that the novel modified borohydrides with the hydrides are that they have a low
ambient temperatures. MIL-53 (Cr) changes 1127–1136.
process was achieved by heating the solvated sequestration of CO 2 . For this it is required
materials, as a large the hydrogen in
they can release expansion in crystallineto study
reaction. Scientists come to the ESRF materials had its pore size and shape in response to Y Filinchuk et al. 2008 Angew. Chem. Int. Ed.
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alanates
mild conditions, whereas if they are too stable, crystalline structures of different M OFs using form, which ended in the material closing to obtain a pure CO 2 (>95%) prior to its
not been observedID31 and BM1,diffraction on beamlines
ESRF to they require a lot of heat to release it.
of reality, for example in Japan and Germany,
ferent Hydrogen-fuelled buses are already a such as
before. This reversible
mostly X-ray powder
although they have
adsorption of molecules such asporosity.
pores with almost no accessible
CO 2 and 47 529–532. in former gas or oil reservoirs
storage, either
ter, fuel generalisapplicationtime away, despitenew regular user group ESRF, isdomain,to the function
“breathing”the also nused microdiffraction theID13.and
action is the in this at team from
similar HThe scientists came to the ESRF to study the
2 O, going from a narrow-pore to a large- or other geological areas of interest.57 732–738.
Y Filinchuk et al. 2009 Acta Mater. As CO
1. A
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is Hamon et al. 2009 J. Am. Chem. Soc.
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ngofto fact that the of lungs in humans: Lavoisier in Versailles (France). size when
they they have managed
grow in pore form.before and after the “breathing”
However, apolar molecules like
4 2
ts automobile industry is starting to the Institut
igh
ryday
associate itself with academic research. As if it was a M eccano, structure
inhaling and go back to their original size CH 4 don’tusing X-rayhave any diffraction.
process, normally powder effect. The 17490–17499.
mixture of CO 2 , CH 4 , CO, H 2S, CH 4 ..., one has
d as M arch 2010 ESRFnews
due to when exhaling. The lungs only expand, breathingthe team is working onFthe the of
Today behaviour of the M O in use P L Llewellyn et al. 2006 Angew. Chem. Int. Ed.
to capture CO 2 with a high selectivity versus
olyte however, by approximately 40% . 17/2/10 14:18:08
presence of gasseparationis not yet clear to
M OFs for their mixtures properties (gases, 45 7751–7754.
the other components. M OFs, with their
n Various solvents (normally water, but also scientists, especially develop biomedical a
liquids) as well as to w hen they contain tunable poreksize, large sorption capacities, Ed.
D Ravnsb æ et al. 2009 Angew. Chem. Int.
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Lithium batteries are widely used in mobile communication devices, such as PDAsone that doesn’t, like CO 2 and CH 4 .
anotherOFs.
iron M or smartphones. nice alternative to zeolites or315 1828–1831.
C Serre et al. 2007 Science amines.
hen Industrial applications on hydrogen Experiments at the ESRF allowed the