Femtosecond laser ultrafast photothermal exsolution

Exsolution,as an effective approach to constructing particle-decorated interfaces,is still challenging to yield interfacial films rather than isolated particles.Inspired by in vivo near-infrared laser photothermal therapy,using 3 mol%Y_(2)O_(3)stabilized tetragonal zirconia polycrystals(3Y-TZP)as host oxide matrix and iron-oxide(Fe3O4/γ-Fe_(2)O_(3)/α-Fe_(2)O_(3))materials as photothermal modulator and exsolution resource,femtosecond laser ultrafast exsolution approach is presented enabling to conquer this challenge.The key is to trigger photothermal annealing behavior via femtosecond laser ablation to initialize phase transition from monoclinic zirconia(m-ZrO_(2))to tetragonal zirconia(t-ZrO_(2))and induce t-ZrO_(2)columnar crystal growth.Fe-ions rapidly segregate along grain boundaries and diffuse towards the outmost surface,and become‘frozen’,highlighting the potential to use photothermal materials and ultrafast heating/quenching behaviors of femtosecond laser ablation for interfacial exsolution.Triggering interfacial iron-oxide coloring exsolution is composition and concentration dependent.Photothermal materials themselves and corresponding photothermal transition capacity play a crucial role,initializing at 2 wt%,3 wt%,and 5 wt%for Fe3O4/γ-Fe_(2)O_(3)/α-Fe_(2)O_(3)doped 3Y-TZP samples.Due to different photothermal effects,exsolution states of ablated 5 wt%Fe_(3)O_(4)/γ-Fe_(2)O_(3)/α-Fe_(2)O_(3)-doped 3Y-TZP samples are totally different,with whole coverage,exhaustion(ablated away)and partial exsolution(rich in the grain boundaries in subsurface),respectively.Femtosecond laser ultrafast photothermal exsolution is uniquely featured by up to now the deepest microscale(10μm from 5 wt%-Fe_(3)O_(4)-3Y-TZP sample)Fe-elemental deficient layer for exsolution and the whole coverage of exsolved materials rather than the formation of isolated exsolved particles by other methods.It is believed that this novel exsolution method may pave a good way to modulate interfacial properties for extensive applications in the fields of biology,optics/photonics,energy,catalysis,environment,etc.

Nanoparticle Exsolution on Perovskite Oxides:Insights into Mechanism,Characteristics and Novel Strategies

Supported nanoparticles have attracted considerable attention as a promising catalyst for achieving unique properties in numerous applications,including fuel cells,chemical conversion,and batteries.Nanocatalysts demonstrate high activity by expanding the number of active sites,but they also intensify deactivation issues,such as agglomeration and poisoning,simultaneously.Exsolution for bottomup synthesis of supported nanoparticles has emerged as a breakthrough technique to overcome limitations associated with conventional nanomaterials.Nanoparticles are uniformly exsolved from perovskite oxide supports and socketed into the oxide support by a one-step reduction process.Their uniformity and stability,resulting from the socketed structure,play a crucial role in the development of novel nanocatalysts.Recently,tremendous research efforts have been dedicated to further controlling exsolution particles.To effectively address exsolution at a more precise level,understanding the underlying mechanism is essential.This review presents a comprehensive overview of the exsolution mechanism,with a focus on its driving force,processes,properties,and synergetic strategies,as well as new pathways for optimizing nanocatalysts in diverse applications.

Exsolutions of Diopside and Magnetite in Olivine from Mantle Dunite,Luobusa Ophiolite,Tibet,China

The exsolutious of diopside and magnetite occur as intergrowth and orient within olivine from the mantle dunite, Luobusa ophiolite, Tibet. The dunite is very fresh with a mineral assemblage of olivine （〉95%） ＋ chromite （1%-4%） ＋ diopside （〈1%）. Two types of olivine are found in thin sections： one （Fo = 94） is coarse-grained, elongated with development of kink bands, wavy extinction and irregular margins; and the other （Fo = 96） is fine-grained and poly-angied. Some of the olivine grains contain minor Ca, Cr and Ni. Besides the exsolutions in olivine, three micron-size inclusions are also discovered. Analyzed through energy dispersive system （EDS） with unitary analytical method, the average compositions of the inclusions are： Na20, 3.12%-3.84%; MgO, 19.51%-23.79%; Al2O3, 9.33%-11.31%; SiO2, 44.89%-46.29%; CaO, 11.46%-12.90%; Cr2O3, 0.74%-2.29%; FeO, 4.26%- 5.27%, which is quite similar to those of amphibole. Diopside is anhedral f＇dling between olivines, or as micro-inclusions oriented in olivines. Chromite appears euhedral distributed between olivines, sometimes with apparent compositional zone. From core to rim of the chromite, Fe content increases and Cr decreases; and A! and Mg drop greatly on the rim. There is always incomplete magnetite zone around the chromite. Compared with the nodular chromite in the same section, the euhedral chromite has higher Fe3O4 and lower MgCr2O4 and MgAI2O4 end member contents, which means it formed under higher oxygen fugacity environment. With a geothermometer estimation, the equilibrium crystalline temperature is 820℃-960℃ for olivine and nodular chromite, 630℃-770℃ for olivine and euhedral chromite, and 350℃-550℃ for olivine and exsoluted magnetite, showing that the exsolutions occurred late at low temperature. Thus we propose that previously depleted mantle harzburgite reacted with the melt containing Na, Al and Ca, and produced an olivine solid solution added with Na^＋, Al^3＋, Ca^2＋, Fe^3＋, Cr^3＋. With temperature decreasing, the olivine solid solution decomposed; and Fe^3＋, Cr^3＋ diffused into magnetite and Ca^2＋ and Na^＋ into clinopyroxene, both of which formed intergrowth textures. A few Fe^3＋ and Cr^3＋ entered interstitial chromite. Through later tectonism, the peridotite recrystallized and formed deformational coarse grained olivine, fine grained and poly-angled olivine, and euhedral grained chromite. Due to the fast cooling rate of the rock or rapid tectonic emplacement, the exsolution textures in olivine and compositional zones of chromite are preserved.

The solution and exsolution characteristics of natural gas components in water at high temperature and pressure and their geological meaning

The processes of solution in, and exsolution from, formation water influence the component content of natural gas by contrasting the relative contents of components before the natural gas dissolves in water and those after exsolving from water under different conditions of high temperatures and pressures. Compared with the composition of original natural gas, the relative content of methane and nitrogen increased after the natural gas dissolved in water. The increase of nitrogen content exceeds that of methane, but the content of ethane, propane, pentane etc reduced. At the same temperature and with pressure increasing the content of methane increased and that of heavier hydrocarbons reduced. At the same pressure the content of methane increased quickly from 90~C to 120~C, and the content of heavier hydrocarbons reduced. But at even higher temperatures, the increase of methane slowed down and the content of heavier hydrocarbons increased slightly. At the same temperature and different pressures, heavier hydrocarbons reduced much more with increasing carbon atom number, while with temperature increasing the content difference of heavier hydrocarbons reduced. Therefore, the influence of the solution and exsolution should be considered in the study of the migration and accumulation mechanism of natural gas.

The Discovery of Phlogopite Exsolution Lamellae in Garnets of Eclogite Inclusions, Liaoning Province

In No. 50 kimberlite pipe of Fuxian County, Liaoning Province, an eclogite inclusion(nodule), which is extremely rare in kimberlites, was discovered and phlogopite exsolutionlamellae were found in garnets of the inclusion. Microscopic, TEM and energy spectral observa-tions and studies confirmed that these lamellae are phlogopite. They are colourless and acicularin section, generally 0.5-5μm in width and 10-100μm in length. Nevertheless, fine lamellae,0.05-0.1μm wide and 1-2μm long, are also well developed. Along [111] of the garnet, three setsof phlogopite lamellae show oriented arrangement approximately at angles of 60°-70°, indi-cating that these lamellae might be the product of exsolution from garnet as a result ofpressure-release when eclogite ascended from the relatively deep level to the relatively shallowlevel of the mantle. Tiny acicular exsolution minerals (or inclusions) are commonly found ingarnet and pyroxene in eclogite inclusions of kimberlites all over the world and it has been re-ported that the identified exsolution minerals include pyroxene and rutile. This is the first timethat phlogopite exsolution lamillae were found in eclogite inclusions in the world.

Raman Spectrum Study on Quartz Exsolution in Omphacite of Eclogite and Its Tectonic Significances

The studies on ultra microstructure characteristics of quartz exsolution in eclogite and coesite in UHP eclogite of several localities are done with the appliance of laser Raman spectroscopy and U stage. Research results show that the phase transformation of coesite quartz in garnet and/or omphacite is a continuous process. Topological relationship is present between quartz exsolution in omphacite and its host mineral which shows orientations of two long axes of quartz exsolution parallel to (100) and (-101) of omphacite. At present, some scholars suggest that the quartz exsolution in omphacite of eclogite is the evidence of UHP metamorphism. However, temperature and pressure condition and the exsolution mechanism of oriented needlelike quartz in omphacite still remain unclear. Therefore, further study should be enhanced on experimental research on exsolution mechanism of super silicate clinopyroxene, which could provide experimental quantitative constraint on quartz exsolution as UHP indicator.

Silver Exsolution-Enhanced Electrical Properties of Lanthanum-Based Perovskites

The effect of silver(Ag)exsolution on the electrical conductivity of strontium-doped lanthanum manganite(La1-x-ySrxAgyMnO3-δ,LSAM)and ferrite(La1-x-ySrxAgyFeO3-δ,LSAF)perovskites was investigated.The single-phase Ag-doped materials formed at 800℃ using modified Pechini method and revealed thermal stability in oxidizing atmosphere up to sintering temperature of the materials at 1,200℃.The exsolution of the metallic Ag nanoparticles was performed at 420-500℃ in reducing atmosphere of 5%H2/N2.Scanning electron microcopy results exhibited the metallic Ag phase nanoparticles on the surface of the oxide backbone with a good contact of Ag to the surface of the perovskite after exsolution.The electrical conductivity of the materials was investigated in the temperature range of 50-900℃ in air and isothermally in 5%H2/N2 at 420 and 500℃ by means of four probe DC measurement method,and reached 80-230 S·cm^-1 for undoped and Ag-doped LSF and LSM.The electrical conductivity results showed improving conductivity in Ag-doped single-phase and Ag nanoparticle decorated perovskites after Ag exsolution.The results revealed the dependence of electrical conductivity on the atmosphere,temperature and Ag exsolution time.

The first observation of Ni nanoparticle exsolution from YSZ and its application for dry reforming of methane

Ni nanocatalysts produced through exsolution have shown strong resistance to particle sintering and carbon coking in a beneficial dry reforming of methane(DRM)reaction utilizing greenhouse gases such as CH_(4)and CO_(2).However,most of the existing oxide supports for exsolution have been limited to perovskite oxide,while studies on fluorite support have been rarely conducted due to the limited solubility despite its excellent redox stability.Here we demonstrate that 3 mol%Ni can be successfully dissolved into the yttria-stabilized zirconia(YSZ)lattice and be further exsolved to the surface in a reducing atmosphere.The YSZ decorated with exsolved Ni nanoparticles shows enhanced catalytic activity for DRM reaction compared to the conventional cermet type of bulk Ni-YSZ.Moreover,the catalytic activity is extremely stable for about 300 h without significant degradation.Overall results suggest that the YSZ-based fluorite structure can be utilized as one of the support oxides for exsolution.

Enhancing layered perovskite ferrites with ultra-high-density nanoparticles via cobalt doping for ceramic fuel cell anode

Nanoparticles anchored on the perovskite surface have gained considerable attention for their wide-ranging applications in heterogeneous catalysis and energy conversion due to their robust and integrated structural configuration.Herein,we employ controlled Co doping to effectively enhance the nanoparticle exsolution process in layered perovskite ferrites materials.CoFe alloy nanoparticles with ultra-high-density are exsolved on the(PrBa)_(0.95)(Fe_(0.8)Co_(0.1)Nb_(0.1))2O_(5+δ)(PBFCN_(0.1))surface under reducing atmosphere,providing significant amounts of reaction sites and good durability for hydrocarbon catalysis.Under a reducing atmosphere,cobalt facilitates the reduction of iron cations within PBFCN_(0.1),leading to the formation of CoFe alloy nanoparticles.This formation is accompanied by a cation exchange process,wherein,with the increase in temperature,partial cobalt ions are substituted by iron.Meanwhile,Co doping significantly enhance the electrical conductivity due to the stronger covalency of the Cosingle bondO bond compared with Fesingle bondO bond.A single cell with the configuration of PBFCN_(0.1)-Sm_(0.2)Ce_(0.8)O_(1.9)(SDC)|SDC|Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)(BSCF)-SDC achieves an extremely low polarization resistance of 0.0163Ωcm^(2)and a high peak power density of 740 mW cm^(−2)at 800℃.The cell also shows stable operation for 120 h in H_(2)with a constant current density of 285 mA cm^(−2).Furthermore,employing wet C_(2)H_(6)as fuel,the cell demonstrates remarkable performance,achieving peak power densities of 455 mW cm^(−2)at 800℃and 320 mW cm^(−2)at 750℃,marking improvements of 36%and 70%over the cell with(PrBa)_(0.95)(Fe_(0.9)Nb_(0.1))_(2)O_(5+δ)(PBFN)-SDC at these respective temperatures.This discovery emphasizes how temperature influences alloy nanoparticles exsolution within doped layered perovskite ferrites materials,paving the way for the development of high-performance ceramic fuel cell anodes.

Ultrahigh pressure (>7 GPa) gneissic K-feldspar (-bearing) garnet clinopyroxenite in the Altyn Tagh, NW China: Evi- dence from clinopyroxene exsolution in garnet

The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume. The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmen- ite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate ig- neous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing lherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deep- subduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western China.

Pore-scale visualization on a depressurization-induced CO2 exsolution

The pore-scale behavior of the exsolved CO_2 phase during the depressurization process in CO_2 geological storage was investigated.The reservoir pressure decreases when the injection stops or when a leaking event or fluid extraction occurs.The exsolution characteristics of CO_2 affect the migration and fate of CO_2 in the storage site significantly.Here,a micromodel experimental system that can accommodate a large pressure variation provides a physical model with homogeneous porous media to dynamically visualize the nucleation and growth of exsolved CO_2 bubbles.The pressure decreased from 9.85 to 3.95 MPa at different temperatures and depressurization rates,and the behavior of CO_2 bubbles was recorded.At the pore-scale,the nuclei became observable when the CO_2 phase density was significantly reduced,and the pressure corresponding to this observation was slightly lower than that of the severe expansion pressure region.The lower temperature and faster depressurization rate produced more CO_2 nuclei.The exsolved CO_2 bubble preferentially grew into the pore body instead of the throat.The progress of smaller CO_2 bubbles merging into a larger CO_2 bubble was first captured,which validated the existence of the Ostwald ripening mechanism.The dispersed CO_2 phase after exsolution shows similarity with the residually trapped CO_2.This observation is consistent with the low mobility and high residual trapping ratio of exsolved CO_2 measured in the core-scale measurement,which is considered to be a self-sealing mechanism during depressurization process in CO_2 geological storage.

Quartz and clinoenstatite exsolutions in clinopyroxene of garnet-pyroxenolite from the North Dabie Mountains,eastern China

The exsolution lamellae of quartz and clinoen-statite are idenfied in diopside of garnet-pyroxenolite from the North Dabie Mountain by transmission electron microscopy, which is interpreted that the lamellae are originally exsolved from a former ultra-high-pressure clinopyroxene due to decreasing of pressure. Study of petrography shows that there is compositional zoning hi the diopside itself. It is implied that the garnet-pyroxenolite had undergone intensive high-temperature granulite fades and high-amphibolitic fades retrogressive metamorphism, while the peridotite (the garnet-pyroxenolite’s host rock) emplaced the

Exsolution of ilmenite and Cr-Ti magnetite from olivine of garnet-wehrlite

Exsolution of rod-like ilmenite (Ilm) and Cr-Ti magnetite (Mt) have been found in olivine of garnet-wehrlite from the core of Chinese Continental Sciences Drilling (CCSD). Their composition, morphology, crystal structure and their topotaxies with host olivine have been studied in detail by the transmission electron microscopy (TEM) and electron probe microanaly- sis (EPMA) technique. It shows that rod-like Ilm exsolution reported in this paper has similar characteristic with that of Alpe Arami olivine, while Cr-Ti magnetite exsolution mentioned in this paper has large discrepancy with chromite exsolution in Alpe Arami olivine. These observations suggest that both of the exsolutions found in this paper should be solid solution phases in β-olivine at their first period, then experiencing decomposition of solid solution and therefore forming Ilm and Cr-Ti magnetite exsolution with the pressure decreasing. So, this garnet-wehrlite perhaps had been ever located in mantle transition zone with a minimum depth of 300 km.

Exsolution of CoFe(Ru)nanoparticles in Ru-doped(La_(0.8)Sr_(0.2))_(0.9)Co_(0.1)Fe_(0.8)Ru_(0.1)O_(3−δ)for efficient oxygen evolution reaction

The rational modification of perovskite oxides(ABO3−δ)is essential to improve the efficiency and stability of oxygen electrolysis.Surface engineering represents a facile approach to modify perovskites for enhanced performance.Through compositional design and in situ exsolution,a Ru-doped(La_(0.8)Sr_(0.2))_(0.9)Co_(0.1)Fe_(0.8)Ru_(0.1)O_(3−δ)(LSCFR)perovskite anchored with CoFe(Ru)alloy particles on the surface was fabricated for oxygen evolution reaction(OER)in this work.Experimental results and calculations indicate that Ru-doping promotes the exsolution of CoFe(Ru)from the perovskite parent.Upon exsolution in the reduced atmosphere for 3 h,the catalyst(LSCFR-3)exhibited superior OER performance with an overpotential of 347 mV and a Tafel slope of 54.65 mV·dec^(−1),and showed good stability in contrast to the pristine LSCFR.The exsolution of CoFe(Ru)particles,Ru doping,and the increase of surface oxygen vacancies are responsible for the enhancement of OER performance.The findings obtained in this study highlight the possibility of controlling exsolution and composition of nanoparticles by element doping and prove that in situ exsolution is an effective strategy for designing OER catalysts.

Slightly ruthenium doping enables better alloy nanoparticle exsolution of perovskite anode for high-performance direct-ammonia solid oxide fuel cells

Fuel flexibility is one of the most distinguished advantages of solid oxide fuel cells(SOFCs)over other low-temperature fuel cells.Furthermore,the combination of ammonia fuel and SOFCs technology should be a promising clean energy system after considering the high energy density,easy transportation/storage,matured synthesis technology and carbon-free nature of NH_(3) as well as high efficiency of SOFCs.However,the large-scale applications of direct-ammonia SOFCs(DASOFCs)are strongly limited by the inferior anti-sintering capability and catalytic activity for ammonia decomposition reaction of conventional nickel-based cermet anode.Herein,a slightly ruthenium(Ru)doping in perovskite oxides is proposed to promote the alloy nanoparticle exsolution,enabling better DA-SOFCs with enhanced power outputs and operational stability.After treating Ru-doped Pr_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.75)Ru_(0.05)O_(3-δ) single-phase perovskite in a reducing atmosphere,in addition to the formation of two layered Ruddlesden-Popper perovskites and Pr_(2)O_(3) nanoparticles(the same as the Ru-free counterpart,Pr_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)),the exsolution of CoFeRu-based alloy nanoparticles is remarkably promoted.Such reduced Pr_(0.6)Sr0.4Co_(0.2)Fe_(0.75)Ru_(0.05)O_(3-δ) composite anode shows superior catalytic activity and stability for NH_(3) decomposition reaction as well as anti-sintering capability in DA-SOFCs to those of reduced Pr0.6Sr0.4Co0.2Fe0.8O_(3-δ)due to the facilitated nanoparticle exsolution and stronger nanoparticle/substrate interaction.This work provides a facile and effective strategy to design highly active and durable anodes for DA-SOFCs,promoting large-scale applications of this technology.

Complex exsolution in Te minerals from the Dashuigou Te deposit

The Dashuigou Te deposit, Sichuan Province, is a unique independent one found up to date in the world. During the mineralogical study of this deposit, the authors observed a number of small vermicular, linear or lamellar minerals in the tsumoite. Such a complex exsolution phenomenon is noted for the first time in Te minerals. The assemblage of tsumoite + exsolution is named complex exsolution zone. We will make detailed study on this exsolution structure and discuss its origin.

In situ observations of tungsten speciation and partitioning behavior during fluid exsolution from granitic melt

Most economically important tungsten(W)deposits are of magmatic-hydrothermal origin.The species and partitioning of W during fluid exsolution,considered to be the controlling factors for the formation of ore deposits,are thus of great significance to investigate.However,this issue has not been well addressed mainly due to the significant difference in reported partition coefficients(e.g.,from strongly incompatible to strongly compatible)between fluid and melt(D_(W)^(fluid/melt)).Here,we used an in situ Raman spectroscopic approach to describe the W speciation,and to quantitatively determine the Dfluid/melt of individual and total W species in granite melts and coexisting Na2WO4 solutions at elevated temperatures(T;700–800C)and pressures(P;0.35–1.08 GPa).Results show that WO_(4)^(2-)and HWO4are predominant W species,and the fractions of these two species are similar in melt and coexisting fluid.The partitioning behaviors of WO_(4)^(2-)and HWO4are comparable,exhibiting strong enrichment in the fluid.The total DW fluid/melt ranges from 8.6 to 37.1.Specifically,DW fluid/melt decreases with rising T–P,indicating that shallow exsolution favors enrichment of W in evolved fluids.Furthermore,Rayleigh fractionation modeling based on the obtained D_(W)^(fluid/melt)data was used to describe the fluid exsolution processes.Our results strongly support that fluid exsolution can serve as an important mechanism to generate W-rich oreforming fluids.This study also indicates that in situ approach can be used to further investigate the geochemical behavior of ore-forming elements during the magmatic-hydrothermal transition,especially for rare metals associated with granite and pegmatite.

In-situ exsolution of cobalt nanoparticles from La_(0.5)Sr_(0.5)Fe_(0.8)Co_(0.2)O_(3-δ) cathode for enhanced CO_(2) electrolysis performance

Solid oxide electrolysis cell(SOEC)is a promising technology for CO_(2) conversion and renewable energy storage with high efficiency.It is highly desirable to develop catalytically active cathodes for CO_(2) electrolysis.Herein,cathode materials with different structural stabilities are designed by Nb substitution on La_(0.5)Sr_(0.5)Fe_(0.8)Co_(0.2)O_(3-δ)(LSFC82)to obtain La_(0.5)Sr_(0.5)Fe_(0.7)Co_(0.2)Nb_(0.1)O_(3-δ)(LSFCN721)and La_(0.5)Sr_(0.5)Fe_(0.8)Co_(0.1)Nb_(0.1)O_(3-δ)(LSFCN811),respectively.LSFC82-Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)cathode with inferior structural stability(ability to maintain the structure)shows desirable CO_(2) electrolysis performance with the generated current density of 1.80 A cm^(-2)2 at 1.6 V and stable performance during 110 h operation at 1.2 V and 800℃.However,LSFC82 particles are collapsed into pieces after stability test with the generation of Co nanoparticles simultaneously.The frameworks of LSFCN721 and LSFCN811 particles maintain well because of the high-valent niobium,but Co exsolution,ox-ygen vacancy content and the corresponding CO_(2) electrolysis performance are restricted.This work confirms that Co nanoparticles can be exsolved from LSFC82-SDC cathode during CO_(2) electrolysis,providing references for constructing metallic nanoparticles decorated-perovskite cathodes for SOECs.

Surface exsolution and local atomic structure of amorphous CeTiO_x

We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel methods and TiO_2 nanoparticles were preferentially generated as a core material to form selective Ce-supersaturated structure on the catalyst surface. Reaction temperature and amount of doping element are optimized to induce selective crystallization of CeO_2. Cee Ce(2 nd shell)bond around 0.38 nm of Ce L3-edge extended X-ray absorption fine structure is reduced and nanostructure of precipitated ceria on the surface is observed by HREM. The catalyst is present as amorphous with precipitated nano-CeO_2 on the surface. The de-NOxefficiency of the catalyst, which has precipitated CeO_2, improves by ~50% owing to the simultaneous reactions of the nano CeO_2 and the amorphous CeTiO_x.

Exsolved materials for CO_(2)reduction in high-temperature electrolysis cells

Electrochemical reduction of CO_(2)into valuable fuels and chemicals has become a contemporary research area,where the heterogeneous catalyst plays a critical role.Metal nanoparticles supported on oxides performing as active sites of electrochemical reactions have been the focus of intensive investigation.Here,we review the CO_(2)reduction with active materials prepared by exsolution.The fundamental of exsolution was summarized in terms of mechanism and models,materials,and driven forces.The advances in the exsolved materials used in hightemperature CO_(2)electrolysis were catalogued into tailored interfaces,synergistic effects on alloy particles,phase transition,reversibility and electrochemical switching.