The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sh...The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.展开更多
CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficien...CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficiency.However,traditional Ni-yttria-stabilized zirconia(Ni-YSZ)or Ni-Gd_(0.1)Ce_(0.9)O_(2-δ)(Ni-GDC)metal-ceramic cathode faces many problems such as Ni agglomeration and carbon deposition during long-time operation.Herein,a perovskite oxide La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)(LCTN,x=0,0.05,0.1)with nanophase-LaVO_(4)exsolution was investigated as the novel cathode of solid oxide electrolysis cell(SOEC)for efficient CO_(2)electrolysis.The results confirm that the exsolution nanophase on LCTN surface can significantly improve the CO_(2)adsorption and conversion performance.For CO_(2)electrolysis at 1.8 V,an electrolysis current density of 1.24 A/cm2at 800℃can be obtained on SOEC with La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)decorated with LaVO_(4)(LCTN-V0.05)cathode.Furthermore,the corresponding cell can maintain stable operation up to 100 h without apparent performance degradation.These results demonstrate that doping-induced second nanophase exsolution is a promising way to design high-performance SOEC cathodes for CO_(2)electrolysis.展开更多
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 demon...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.展开更多
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 the...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.展开更多
Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on...Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.展开更多
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%） ＋ chr...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.展开更多
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...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.展开更多
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 ...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.展开更多
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 inclu...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.展开更多
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 re...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.展开更多
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 met...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.展开更多
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_(...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.展开更多
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...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.展开更多
Traditional surface modification methods such as physical or chemical vapor deposition and impregnation have been widely used to modify perovskite surfaces.However,there is weak interaction between metal nanoparticles...Traditional surface modification methods such as physical or chemical vapor deposition and impregnation have been widely used to modify perovskite surfaces.However,there is weak interaction between metal nanoparticles(NPs)loaded via these methods and the perovskite oxide support,which may lead to issues such as deactivation during application owing to poor stability,easy agglomeration,and carbon deposition.Exsolution refers to the in-situ growth of NPs on the surface of parent oxides.The presence of NPs increases the number of active sites for the reaction,and NPs exhibit strong interaction with the matrix,showing excellent catalytic performance and high stability.Therefore,in recent years,the field of in-situ exsolution has received extensive attention.Based on this,this paper starts from exsolution phenomena of perovskite oxides,reviews existing exsolution methods,sorts out structurally regulated exsolution strategies of perovskite oxides in terms of A-site defects,B-site cation dopants,and phase transformation,introduces application fields of the in-situ exsolution,and provides prospect.展开更多
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 pe...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.展开更多
The exsolution method has garnered significant attention owing to its high efficacy in developing highly efficient and stable metal nanocatalysts.Herein,a versatile exsolution approach is developed to embed size-tunab...The exsolution method has garnered significant attention owing to its high efficacy in developing highly efficient and stable metal nanocatalysts.Herein,a versatile exsolution approach is developed to embed size-tunable metal nanocatalysts within a conductive metal pnictogenide matrix.The gas-phase reaction of Ru-substituted Ni-Fe-layered-double-hydroxide(Ni_(2)Fe_(1-x)Ru_(x)-LDH)with pnictogenation reagents leads to the exsolution of Ru metal nanocatalysts and a phase transformation into metal pnictogenide.The variation in reactivity of pnictogenation reagents allows for control over the size of the exsolved metal nanocatalysts(i.e.,nanoclusters for nitridation and single atoms for phosphidation),underscoring the effectiveness of the pnictogenation-driven exsolution strategy in stabilizing size-tunable metal nanocatalysts.The Ru-exsolved nickel-iron nitride/phosphide demonstrates outstanding electrocatalyst activity for the hydrogen evolution reaction,exhibiting a smaller overpotential and higher stability than Ru-deposited homologs.The high efficacy of pnictogenation-assisted exsolution in optimizing the performance and stability of Ru metal nanocatalysts is ascribed to the efficient interfacial electronic interaction between Ru metals and nitride/phosphide ions assisted by the inner sphere mechanism.In situ spectroscopic analyses highlight that exsolved Ru single atoms facilitate more efficient electron transfer to the reactants than the exsolved Ru nanoclusters,which is primarily responsible for the superior impact of the phosphidation-driven exsolution approach.展开更多
Advancing clean energy technologies demands efficient and durable electrode catalysts for solid oxide cells(SOCs).Despite their exceptional catalytic properties,Pt-based materials face critical challenges in high-temp...Advancing clean energy technologies demands efficient and durable electrode catalysts for solid oxide cells(SOCs).Despite their exceptional catalytic properties,Pt-based materials face critical challenges in high-temperature applications owing to particle agglomeration and cost constraints.Here,we demonstrate a rational design strategy utilizing controlled in situ exsolution to create strongly anchored PtSn nanoalloys on oxygen-deficient PrBaMn_(1.8)Pt_(0.1)Sn_(0.1)O_(5+δ)(L-PBMPtSn)perovskite oxide.Through precise compositional engineering and structural control,we achieved a uniform dispersion of PtSn nanoparticles with unique socket-like interfaces that prevent agglomeration while maintaining high catalytic accessibility.The optimized electrode demonstrates remarkable bifunctional performance,achieving a current density of 1.6 A cm^(-2)at 1.8 V for CO_(2)electrolysis and a maximum power density of 316 mW cm^(-2)for fuel cell operation at 800℃.More significantly,the electrode exhibits exceptional stability with only 9.6%performance degradation over 100 h of operation,which is a substantial improvement over conventional electrodes.Our findings establish a new paradigm for designing high-performance SOC electrodes through the controlled exsolution of precious metal alloys,offering broader implications for catalyst design in high-temperature electrochemical systems.展开更多
Reversible solid oxide cells(RSOCs)are capable of converting various energy resources,between electricity and chemical fuels,with high efficiency and flexibility,making them suitable for grid balancing and renewable e...Reversible solid oxide cells(RSOCs)are capable of converting various energy resources,between electricity and chemical fuels,with high efficiency and flexibility,making them suitable for grid balancing and renewable energy consumption.However,the practical application of RSOCs is still limited by the insufficient activity and stability of the electrodes in different operating modes.Herein,a highly efficient symmetrical electrode composed of La_(0.3)Sr_(0.6)Ti_(0.1)Co_(0.2)Fe_(0.7)O_(3-δ)(LSTCF)nanofibers and in situ exsolved Co_(3)Fe_(7) nanoparticles is developed for boosting the performance of RSOCs.The reversible phase transition,high activity and stability of the electrode have been confirmed by a combination of experimental(e.g.,transmission electron microscopy and X-ray absorption fine structure)and computational studies.Electrolyte-supported RSOCs with the symmetrical electrode demonstrate excellent catalytic activity and stability,achieving a high peak power density of 0.98 W cm^(-2)in the fuel cell mode using H_(2)as the fuel(or 0.53 W cm^(-2)using CH_(4)as the fuel)and a high current density of 1.09 A cm^(-2) at 1.4 V in the CO_(2)electrolysis mode(or 1.03 A cm^(-2)at 1.3 V for H_(2)O electrolysis)at 800℃while maintaining excellent durability for over 100 h.展开更多
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...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.展开更多
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 f...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.展开更多
基金funded by the National Natural Science Foundation of China(grant 42102094)Natural Science Foundation of Hebei(Grant D2022402028).
文摘The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.
基金Project supported by the National Key Research&Development Project(2023YFB4006001)National Natural Science Foundation of China(52172199)。
文摘CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficiency.However,traditional Ni-yttria-stabilized zirconia(Ni-YSZ)or Ni-Gd_(0.1)Ce_(0.9)O_(2-δ)(Ni-GDC)metal-ceramic cathode faces many problems such as Ni agglomeration and carbon deposition during long-time operation.Herein,a perovskite oxide La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)(LCTN,x=0,0.05,0.1)with nanophase-LaVO_(4)exsolution was investigated as the novel cathode of solid oxide electrolysis cell(SOEC)for efficient CO_(2)electrolysis.The results confirm that the exsolution nanophase on LCTN surface can significantly improve the CO_(2)adsorption and conversion performance.For CO_(2)electrolysis at 1.8 V,an electrolysis current density of 1.24 A/cm2at 800℃can be obtained on SOEC with La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)decorated with LaVO_(4)(LCTN-V0.05)cathode.Furthermore,the corresponding cell can maintain stable operation up to 100 h without apparent performance degradation.These results demonstrate that doping-induced second nanophase exsolution is a promising way to design high-performance SOEC cathodes for CO_(2)electrolysis.
基金This study was supported by the National Research Foundation of Korea(NRF-2021R1C1C1010233)funded by the Korean government(MSIT)+1 种基金This research was also supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)Grant(No.G032542411)funded by the Korea Ministry of Trade,Industry,and Energy(MOTIE).
文摘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.
基金financially supported by Shanghai Pujiang Program 23PJ1406500.
文摘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.
基金supported by Australian Research Council Discovery Projects(DP230101625 and DP200103568)Australian Research Council Future Fel owships(FT180100387 and FT160100281)QUT ECR Scheme Grant(no.2020001179)
文摘Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.
文摘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.
基金financially supported by the National Natural Science Foundation of China(Nos.22108121,21908106 and21878158)Jiangsu Natural Science Foundation(No.BK20190682)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘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.
文摘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.
文摘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.
文摘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.
基金Project supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)through GCRC-SOP(2011-0030013)
文摘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.
基金This work was supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20173020032120)This work also was supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2019R1C1C1005801)Partial support from“CO2 utilization battery for hydrogen production based on fault-tolerance deep learning”(1.200097.01)is also acknowledged.
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.51354001 and 51601086)the Liaoning BaiQianWan Talents Program(2018B014)the 2024 Fundamental Research Funding of the Educational Department of Liaoning Province.
文摘Traditional surface modification methods such as physical or chemical vapor deposition and impregnation have been widely used to modify perovskite surfaces.However,there is weak interaction between metal nanoparticles(NPs)loaded via these methods and the perovskite oxide support,which may lead to issues such as deactivation during application owing to poor stability,easy agglomeration,and carbon deposition.Exsolution refers to the in-situ growth of NPs on the surface of parent oxides.The presence of NPs increases the number of active sites for the reaction,and NPs exhibit strong interaction with the matrix,showing excellent catalytic performance and high stability.Therefore,in recent years,the field of in-situ exsolution has received extensive attention.Based on this,this paper starts from exsolution phenomena of perovskite oxides,reviews existing exsolution methods,sorts out structurally regulated exsolution strategies of perovskite oxides in terms of A-site defects,B-site cation dopants,and phase transformation,introduces application fields of the in-situ exsolution,and provides prospect.
基金the National Natural Science Foundation of China(No.51901161)Natural Science Foundation of Guangdong Province(No.2021A1515011955)+2 种基金College Innovation Team Project of Guangdong Province(No.2021KCXTD042)Major Projects of Guangdong Education Department for Foundation Research and Applied Research(No.2020ZDZX2063)Wuyi University-Hong Kong-Macao Joint Research and Development Fund(No.2019WGALH06).
文摘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.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2023-00208355,RS-2024-00439825,and 2022M3H4A408610313)supported by the Global Science Research Center Program(RS-2024-00411134)+1 种基金funded by the National Research Foundation of KoreaThe experiments at PAL were supported in part by MOST and POSTECH。
文摘The exsolution method has garnered significant attention owing to its high efficacy in developing highly efficient and stable metal nanocatalysts.Herein,a versatile exsolution approach is developed to embed size-tunable metal nanocatalysts within a conductive metal pnictogenide matrix.The gas-phase reaction of Ru-substituted Ni-Fe-layered-double-hydroxide(Ni_(2)Fe_(1-x)Ru_(x)-LDH)with pnictogenation reagents leads to the exsolution of Ru metal nanocatalysts and a phase transformation into metal pnictogenide.The variation in reactivity of pnictogenation reagents allows for control over the size of the exsolved metal nanocatalysts(i.e.,nanoclusters for nitridation and single atoms for phosphidation),underscoring the effectiveness of the pnictogenation-driven exsolution strategy in stabilizing size-tunable metal nanocatalysts.The Ru-exsolved nickel-iron nitride/phosphide demonstrates outstanding electrocatalyst activity for the hydrogen evolution reaction,exhibiting a smaller overpotential and higher stability than Ru-deposited homologs.The high efficacy of pnictogenation-assisted exsolution in optimizing the performance and stability of Ru metal nanocatalysts is ascribed to the efficient interfacial electronic interaction between Ru metals and nitride/phosphide ions assisted by the inner sphere mechanism.In situ spectroscopic analyses highlight that exsolved Ru single atoms facilitate more efficient electron transfer to the reactants than the exsolved Ru nanoclusters,which is primarily responsible for the superior impact of the phosphidation-driven exsolution approach.
基金supported by the National Natural Science Foundation of China(Nos.22272081 and 52473235)Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.KYCX24_1527)National Research Foundation of Korea(NRF)grant funded by the Korea governement(MSIT)(No.RS-2024-00347253)
文摘Advancing clean energy technologies demands efficient and durable electrode catalysts for solid oxide cells(SOCs).Despite their exceptional catalytic properties,Pt-based materials face critical challenges in high-temperature applications owing to particle agglomeration and cost constraints.Here,we demonstrate a rational design strategy utilizing controlled in situ exsolution to create strongly anchored PtSn nanoalloys on oxygen-deficient PrBaMn_(1.8)Pt_(0.1)Sn_(0.1)O_(5+δ)(L-PBMPtSn)perovskite oxide.Through precise compositional engineering and structural control,we achieved a uniform dispersion of PtSn nanoparticles with unique socket-like interfaces that prevent agglomeration while maintaining high catalytic accessibility.The optimized electrode demonstrates remarkable bifunctional performance,achieving a current density of 1.6 A cm^(-2)at 1.8 V for CO_(2)electrolysis and a maximum power density of 316 mW cm^(-2)for fuel cell operation at 800℃.More significantly,the electrode exhibits exceptional stability with only 9.6%performance degradation over 100 h of operation,which is a substantial improvement over conventional electrodes.Our findings establish a new paradigm for designing high-performance SOC electrodes through the controlled exsolution of precious metal alloys,offering broader implications for catalyst design in high-temperature electrochemical systems.
基金supported by the National Natural Science Foundation of China(No.52377212 and 51877173)program of Beijing Huairou Laboratory(ZD2022006A)+2 种基金the Key R&D Project of Shaanxi Province(2023-YBGY-057)the State Key Laboratory of Electrical Insulation and Power Equipment(EIPE22314,EIPE22306)the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0483).
文摘Reversible solid oxide cells(RSOCs)are capable of converting various energy resources,between electricity and chemical fuels,with high efficiency and flexibility,making them suitable for grid balancing and renewable energy consumption.However,the practical application of RSOCs is still limited by the insufficient activity and stability of the electrodes in different operating modes.Herein,a highly efficient symmetrical electrode composed of La_(0.3)Sr_(0.6)Ti_(0.1)Co_(0.2)Fe_(0.7)O_(3-δ)(LSTCF)nanofibers and in situ exsolved Co_(3)Fe_(7) nanoparticles is developed for boosting the performance of RSOCs.The reversible phase transition,high activity and stability of the electrode have been confirmed by a combination of experimental(e.g.,transmission electron microscopy and X-ray absorption fine structure)and computational studies.Electrolyte-supported RSOCs with the symmetrical electrode demonstrate excellent catalytic activity and stability,achieving a high peak power density of 0.98 W cm^(-2)in the fuel cell mode using H_(2)as the fuel(or 0.53 W cm^(-2)using CH_(4)as the fuel)and a high current density of 1.09 A cm^(-2) at 1.4 V in the CO_(2)electrolysis mode(or 1.03 A cm^(-2)at 1.3 V for H_(2)O electrolysis)at 800℃while maintaining excellent durability for over 100 h.
基金the National Key Basic Research Program of China(Grant No. 1999075508) the National Natural Science Foundation of China(Grant Nos.40372088,49972063 , 140032010-c)+1 种基金the Cadreman Teacher Foundation of the Ministry of Education of China (Grant No. 40133020) the Open Foundation of the Laboratory of Orogen and Basin of the Ministry of Education of Peking University.
文摘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.
基金supported by the National Key Research and Development Plan(2016YFB0600804)National Natural Science Foundation of China(51536004,51376104)
文摘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.
