Aplicações          Prof.
Maliska      Daphiny
posdoc          ...
SiO2                                   S A X S and D LS study of silica nanoparticle formatio...
g the next bestmonds, is not the only element that is  to hardness. Boron and nitrogen also                            hig...
tor, and vice versa splacements leading to the newetallisation takes place due toygen, are insulating at room temperature,...
Focus on: extreme conditionsrthCondições
terra    to its surface from the centre             Take a t...
histication. The researchers  ut have never clearly                            their work will Research light on          ...
of Kiel (Germany) and the                                       stable, to room temperature.  found a rapid synthesis of a...
Poliméricas   A Mercedes Benz Citaro London bus running on fuel cells. This kind of bus was first used ...
structure before and after the “breathing”             is produced by industry within a complex                           ...
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
[Aplicacoes] Estrutura Cristalina de Solidos
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[Aplicacoes] Estrutura Cristalina de Solidos


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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

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[Aplicacoes] Estrutura Cristalina de Solidos

  1. 1. Estrutural
 Aplicações Prof.
Maliska Daphiny
posdoc 21‐set‐2011.
  2. 2. Nucleação
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.
 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
5377–5393A ggregation 2 7.9 —r of S A X S <3%.
  3. 3. g the next bestmonds, 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
 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 isafter 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 substitutesuth (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 alsough 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 1956mond, 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 thaDespite the fact that it was synthesised the production, the material decomposes, and A DNRs. ABNN C also has unusually highyears 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 hasmelight (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 decidedap,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 Tnancial 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-hardard 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 desby 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. 4. tor, and vice versa splacements leading to the newetallisation takes place due toygen, are insulating at room temperature, but if you put themf the band gap that occurs with to conducto O2,
Isolante‐Condutor? oxygen of the that don’t have electrical resistance. The other way erials lattice, which evolves intocture 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 eood quality single crystals at these Composite diffraction image: data from the one of the phases of sodium with 90 atoms in unit cell. utexplains 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 lighterwsified 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) discoveredand 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
pressao/temperaturasmall region of highscientists have only recently determined the emes transparent, using Raman phases are reached in a very therefore high pressure, and density M Capellas “Sodiumy 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 onering 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 actuallyodium 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. 5. Focus on: extreme conditionsrthCondições
terra to its surface from the centre Take a trip The Earth is still an enigma. The Earth’s layersN 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
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
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
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. 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
 ,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- acteriaolecular crystallography unveils (US), SCK. bacteria
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. 7. of Kiel (Germany) and the stable, to room temperature. found a rapid synthesis of an Because the researchers discovered thathis well studied material.2 O 8 had been thought to be Síntese
 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 mayall temperatures and, unlike requiring MoO4 tetrahedra inon: time-resolved studies Focus yellow. it had not been possible to no longer be necessary.follow the synthesisrectly from the constituent ow. John Evans, leader of the team, from Durham University, comments thatmaterial as it happenshers noticed in their lab that “the use of extremely rapid quantitativeable to form the supposedly powder diffraction at the ESRF was crucialbic 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 Capellase team used the ID11 beamlineall synthesis of the new material. This camera was symmetry forces them to contract equally insitu 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 synthesisraction. 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. 8. Células
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 thehe 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 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 waterprimary 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 theeady 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 fuelon 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 measuredues 0.5 and 5 A locomotion. The variable working conditions, the water in a running fuel-cell membrane for instance because of the request ofmembrane layer by layer from the H 2 in real-life conditions. For this experiment, rapid increase of power supply during thelectrode, 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.
 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:
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.


 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
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. 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

 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
futuro ng gases: a key for a greener futureore 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 theheul 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 imagineing 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,unityes 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 andhydrides, 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.mides physical properties.” Scientists aim for unstable by a physisorption process and not a redox 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 stable but of hydrogen as a A activeH ), in cars still some of 2 is Hamon et al. 2009 J. Am. Chem. Soc. L produced by industry within a complex 131ngofto 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 ESRFnewsdue 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 versusolyte 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 theirn 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. alcohols) entering the materials open their component that provokes breathing and applications using non-toxic biodegradable 48 6659–6663. good selectivity and easy regeneration, offer a ted cavities. This makes the structures grow, 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