Ni-Doped Pr0.7Ba0.3MnO3-δ Cathodes for Enhancing Electrolysis of CO2 in Solid Oxide Electrolytic Cells.

Solid Oxide Electrolysis Cells (SOECs) can electro-reduce carbon dioxide to carbon monoxide, which not only effectively utilizes greenhouse gases, but also converts excess electrical energy into chemical energy. Perovskite-based oxides with exsolved metal nanoparticles are promising cathode materials for direct electrocatalytic reduction of CO2 through SOECs, and have thus received increasing attention. In this work, we doped Pr0.7Ba0.3MnO3-δ at the B site, and after reduction treatment, metal nanoparticles exsolved and precipitated on the surface of the cathode material, thereby establishing a stable metal-oxide interface structure and significantly improving the electrocatalytic activity of the SOEC cathode materials. Through research, among the Pr0.7Ba0.3Mn1-xNixO3-δ (PBMNx = 0-1) cathode materials, it has been found that the Pr0.7Ba0.3Mn0.9Ni0.1O3-δ (PBMN0.1) electrode material exhibits greater catalytic activity, with a CO yield of 5.36 mL min-1 cm-2 and a Faraday current efficiency of ~99%. After 100 h of long-term testing, the current can still remain stable and there is no significant change in performance. Therefore, the design of this interface has increasing potential for development.

Rutile-Type Co0.5Ti0.5NbO4-Based Cathode with In Situ Exsolved Metal Particles for Direct CO2 Electrolysis.

Rutile-type Co0.5Ti0.5NbO4 (CTO)-based materials doped with Fe3+ or Ni2+ were investigated as cathode electrodes to modify their electrical conductivity and electrocatalysis toward CO2 splitting. Higher electric conductivity was found in Co0.4Fe0.2Ti0.4NbO4 (CTO-Fe, 0.78 S cm-1) and Co0.25Ni0.25Ti0.5NbO4 (CTO-Ni, 2.10 S cm-1) compared to CTO (0.49 S cm-1) after the reduction at 800 °C in Ar-5% H2. Co and Co-Ni particles exsolved in situ from the surface of CTO, CTO-Fe, and CTO-Ni after reduction. CTO-Ni and CTO-Fe cathodes did better in the CO2 electrolysis at 800 °C than the CTO one, but the CTO-Ni cell was unstable after 10 h of operation due to the carbon deposition that blocked the electrode. The cell with CTO-Fe demonstrated a good stability for CO2 splitting in 100 h. This work demonstrates that rutile-type CTO-based cathodes are promising to provide an efficient and candidate oxide cathode for the electrolysis of CO2.

In Situ Exsolution-Prepared Solid-Solution-Type Sulfides with Intracrystal Polarization for Efficient and Selective Absorption of Low-Frequency Electromagnetic Wave.

The excellent dielectric properties and tunable structural design of metal sulfides have attracted considerable interest in realizing electromagnetic wave (EMW) absorption. However, compared with traditional monometallic and bimetallic sulfides that are extensively studied, the unique physical characteristics of solid-solution-type sulfides in response to EMW have not been revealed yet. Herein, a unique method for preparing high-purity solid-solution-type sulfides is proposed based on solid-phase in situ exsolution of different metal ions from hybrid precursors. Utilizing CoAl-LDH/MIL-88A composite as a precursor, Fe0.8Co0.2S single-phase nanoparticles are uniformly in situ formed on an amorphous substrate (denoted as CoAl), forming CoAl/Fe0.8Co0.2S heterostructure. Combing with density functional theory (DFT) calculations and wave absorption simulations, it is revealed that Fe0.8Co0.2S solid solution has stronger intracrystal polarization and electronic conductivity than traditional monometallic and bimetallic sulfides, which lead to higher dielectric properties in EM field. Therefore, CoAl/Fe0.8Co0.2S heterostructure exhibits significantly enhanced EMW absorption ability in the low-frequency region (2-6 GHz) and can achieve frequency screening by selectively absorbing EMW of specific frequency. This work not only provides a unique method for preparing high-purity solid-solution-type sulfides but also fundamentally reveals the physical essence of their excellent EMW absorption performance.

A High-Entropy Layered Perovskite Coated with In Situ Exsolved Core-Shell CuFe@FeOx Nanoparticles for Efficient CO2 Electrolysis.

Solid oxide electrolysis cells (SOECs) are promising energy conversion devices capable of efficiently transforming CO2 into CO, reducing CO2 emissions, and alleviating the greenhouse effect. However, the development of a suitable cathode material remains a critical challenge. Here a new SOEC cathode is reported for CO2 electrolysis consisting of high-entropy Pr0.8 Sr1.2 (CuFe)0.4 Mo0.2 Mn0.2 Nb0.2 O4-δ (HE-PSCFMMN) layered perovskite uniformly coated with in situ exsolved core-shell structured CuFe alloy@FeOx (CFA@FeO) nanoparticles. Single cells with the HE-PSCFMMN-CFA@FeO cathode exhibit a consistently high current density of 1.95 A cm-2 for CO2 reduction at 1.5 V while maintaining excellent stability for up to 200 h under 0.75 A cm-2 at 800 °C in pure CO2 . In situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations confirm that the exsolution of CFA@FeO nanoparticles introduces additional oxygen vacancies within HE-PSCFMMN substrate, acting as active reaction sites. More importantly, the abundant oxygen vacancies in FeOx shell, in contrast to conventional in situ exsolved nanoparticles, enable the extension of the triple-phase boundary (TPB), thereby enhancing the kinetics of CO2 adsorption, dissociation, and reduction.

Enhanced CO2 Electrolysis Through Mn Substitution Coupled with Ni Exsolution in Lanthanum Calcium Titanate Electrodes.

In this study, perovskite oxides La0.3 Ca0.6 Ni0.05 Mnx Ti0.95- x O3- γ (x = 0, 0.05, 0.10) are investigated as potential solid oxide electrolysis cell cathode materials. The catalytic activity of these cathodes toward CO2 reduction reaction is significantly enhanced through the exsolution of highly active Ni nanoparticles, driven by applying a current of 1.2 A in 97% CO2 - 3% H2 O. The performance of La0.3 Ca0.6 Ni0.05 Ti0.95 O3-γ is notably improved by co-doping with Mn. Mn dopants enhance the reducibility of Ni, a crucial factor in promoting the in situ exsolution of metallic nanocatalysts in perovskite (ABO3 ) structures. This improvement is attributed to Mn dopants enabling more flexible coordination, resulting in higher oxygen vacancy concentration, and facilitating oxygen ion migration. Consequently, a higher density of Ni nanoparticles is formed. These oxygen vacancies also improve the adsorption, desorption, and dissociation of CO2 molecules. The dual doping strategy provides enhanced performance without degradation observed after 133 h of high-temperature operation, suggesting a reliable cathode material for CO2 electrolysis.

High-Performance Co-production of Electricity and Light Olefins Enabled by Exsolved NiFe Alloy Nanoparticles from a Double-Perovskite Oxide Anode in Solid Oxide-Ion-Conducting Fuel Cells.

Light olefins (LOs) such as ethylene and propylene are critical feedstocks for many vital chemicals that support our economy and daily life. LOs are currently mass produced via steam cracking of hydrocarbons, which is highly energy intensive and carbon polluting. Efficient, low-emission, and LO-selective conversion technologies are highly desirable. Electrochemical oxidative dehydrogenation of alkanes in oxide-ion-conducting solid oxide fuel cell (SOFC) reactors has been reported in recent years as a promising approach to produce LOs with high efficiency and yield while generating electricity. We report here an electrocatalyst that excels in the co-production. The efficient catalyst is NiFe alloy nanoparticles (NPs) exsolved from a Pr- and Ni-doped double perovskite Sr2Fe1.5Mo0.5O6 (Pr0.8Sr1.2Ni0.2Fe1.3Mo0.5O6-δ, PSNFM) matrix during SOFC operation. We show evidence that Ni is first exsolved, which triggers the following Fe-exsolution, forming the NiFe NP alloy. At the same time as the NiFe exsolution, abundant oxygen vacancies are created at the NiFe/PSNFM interface, which promotes the oxygen mobility for oxidative dehydrogenation of propane (ODHP), coking resistance, and power generation. At 750 °C, the SOFC reactor with the PSNFM catalyst reaches a propane conversion of 71.40% and LO yield of 70.91% under a current density of 0.3 A cm-2 without coking. This level of performance is unmatchable by the current thermal catalytic reactors, demonstrating the great potential of electrochemical reactors for direct hydrocarbon conversion into value-added products.

Ni/NiO Exsolved Perovskite La0.2Sr0.7Ti0.9Ni0.1O3-δ for Semiconductor-Ionic Fuel Cells: Roles of Electrocatalytic Activity and Physical Junctions.

A semiconductor-ionic fuel cell (SIFC) is recognized as a promising technology and an alternative approach to reduce the operating temperature of solid oxide fuel cells. The development of alternative semiconductors substituting easily reduced transition metal oxide is a great challenge as high activity and durability should be satisfied simultaneously. In this study, the B-site Ni-doped La0.2Sr0.7Ti0.9Ni0.1O3-δ (LSTN) perovskite is synthesized and used as a potential semiconductor for SIFC. The in situ exsolution and A-site deficiency strategy enable the homogeneous decoration of Ni/NiO nanoparticles as reactive sites to improve the electrode reaction kinetics. It also supports the formation of basic ingredient of the Schottky junction to improve the charge separation efficiency. Furthermore, additional symmetric Ni0.8Co0.15Al0.05LiO2-δ (NCAL) electrocatalytic electrode layers significantly enhance the electrode reaction activity and cells' charge separation efficiency, as confirmed by the superior open circuit voltage of 1.13 V (close to Nernst's theoretical value) and peak power density of 650 mW cm-2 at 550 °C, where the latter is one order of magnitude higher than NCAL electrode-free SIFC. Additionally, a bulk heterojunction effect is proposed to illustrate the electron-blocking and ion-promoting processes of the semiconductor-ionic composite electrolyte in SIFCs, based on the energy band values of the applied materials. Overall, we found that the energy conversion efficiency of novel SIFC can be remarkably improved through in situ exsolution and intentional introduction of the catalytic functionality.

Ti/Ni co-doped perovskite cathode with excellent catalytic activity and CO2 chemisorption ability via nanocatalysts exsolution for solid oxide electrolysis cell.

Carbon dioxide (CO2) gas is the main cause of global warming and has a significant effect on both climate change and human health. In this study, Ni/Ti co-doped Sr1.95Fe1.2Ni0.1Ti0.2Mo0.5O6-δ (SFNTM) double perovskite oxides were prepared and used as solid oxide electrolysis cell (SOEC) cathode materials for effective CO2 reduction. Ti-doping enhances the structural stability of the cathode material and increases the oxygen vacancy concentration. After treatment in 10% H2/Ar at 800°C, Ni nanoparticles were exsolved in situ on the SFNTM surface (Ni@SFNTM), thereby improving its chemisorption and activation capacity for CO2. Modified by the Ti-doping and the in situ exsolved Ni nanoparticles, the single cell with Ni@SFNMT cathode exhibits improved catalytic activity for CO2 reduction, exhibiting a current density of 2.54 A cm-2 at 1.8 V and 800°C. Furthermore, the single cell shows excellent stability after 100 h at 1.4 V, indicating that Ni/Ti co-doping is an effective strategy for designing novel cathode material with high electrochemical performance for SOEC.

Synergistically Promoting Coking Resistance of a La0.4Sr0.4Ti0.85Ni0.15O3-δ Anode by Ru-Doping-Induced Active Twin Defects and Highly Dispersed Ni Nanoparticles.

The development of anodes with highly efficient electrochemical catalysis and good durability is crucial for solid oxide fuel cells (SOFCs). This paper reports a superior Ru-doped La0.4Sr0.4Ti0.85Ni0.15O3-δ (L0.4STN) anode material with excellent catalytic activity and good stability. The doping of Ru can inhibit the agglomeration of in situ-exsolved Ni nanoparticles on the surface and induce the formation of abundant multiple-twinned defects in the perovskite matrix, which significantly increase the concentration of oxygen vacancies. The reduced L0.4STRN (R-L0.4STRN) anode shows an area-specific resistance (ASR) of 0.067 Ω cm2 at 800 °C, which is only about one-third of that of stochiometric R-L0.6STN (0.212 Ω cm2). A single cell with the R-L0.4STRN anode shows excellent stability (∼50 h at 650 °C) in both H2 and CH4. Furthermore, R-L0.4STRN exhibits outstanding resistance to carbon deposition, which can be attributed to the synergistic effect of highly dispersed Ni nanoparticles and active twinned defects induced by Ru doping.

Perovskite Oxyfluoride Ceramic with In Situ Exsolved Ni-Fe Nanoparticles for Direct CO2 Electrolysis in Solid Oxide Electrolysis Cells.

Solid oxide electrolysis cell (SOEC) is a potential technique to efficiently convert CO2 greenhouse gas into valuable fuels. Thus, there is significant interest in developing highly active and stable electrocatalysts for the CO2 reduction reaction (CO2RR). Herein, a Ni and F co-doping strategy is proposed to facilitate the exsolution reaction and form a new cathode, Ni-Fe alloy nanoparticles embedded in ceramic Sr2Fe1.5Mo0.5O6-δ (SFM) doped with fluorine. F-doping and Ni-Fe exsolution enhance CO2 adsorption by a factor of 2.4 and increase the surface reaction rate constant (kchem) for CO2RR from 6.79 × 10-5 to 18.1 × 10-5 cm s-1, as well as the oxygen chemical bulk diffusion coefficient (Dchem) from 9.42 × 10-6 to 19.1 × 10-6 cm2 s-1 at 800 °C. Meanwhile, the interfacial polarization resistance (Rp) decreases by 52%, from 0.64 to 0.31 Ω cm2. At 800 °C and 1.5 V, an extremely high current density of 2.66 A cm-2 and a stability test over 140 h are achieved for direct CO2 electrolysis in the SOEC.

A Robust Approach to In Situ Exsolve Highly Dispersed and Stable Electrocatalysts.

Catalysts made of in situ exsolved metal nanoparticles often demonstrate promising activity and high stability in many applications. However, the traditional approach is limited by perovskites as prevailing precursor and requires high temperature typically above 900 K. Here, with the guidance of theoretical calculation, an unprecedented and substantially facile technique is demonstrated for Cu nanoparticles exsolved from interstitially Cu cations doped nickel-based hydroxide, which is accomplished swiftly at room temperature and results in metal nanoparticles with a quasi-uniform size of 4 nm, delivering an exceptional CO faradaic efficiency of 95.6% for the electrochemical reduction of CO2 with a notable durability. This design principle is further proven to be generally applicable to other metals and foregrounded for guiding the development of advanced catalytic materials.

Atomic cerium modulated palladium nanoclusters exsolved ferrite catalysts for lean methane conversion.

The active and stable palladium (Pd) based catalysts for CH4 conversion are of great environmental and industrial significance. Herein, we employed N2 as an optimal activation agent to develop a Pd nanocluster exsolved Ce-incorporated perovskite ferrite catalyst toward lean methane oxidation. Replacing the traditional initiator of H2, the N2 was found as an effective driving force to selectively touch off the surface exsolution of Pd nanocluster from perovskite framework without deteriorating the overall material robustness. The catalyst showed an outstanding T50 (temperature of 50% conversion) plummeting down to 350°C, outperforming the pristine and H2-activated counterparts. Further, the combined theoretical and experimental results also deciphered the crucial role that the atomically dispersed Ce ions played in both construction of active sites and CH4 conversion. The isolated Ce located at the A-site of perovskite framework facilitated the thermodynamic and kinetics of the Pd exsolution process, lowering its formation temperature and promoting its quantity. Moreover, the incorporation of Ce lowered the energy barrier for cleavage of C─H bond, and was dedicated to the preservation of highly reactive PdOx moieties during stability measurement. This work successfully ventures uncharted territory of in situ exsolution to provide a new design thinking for a highly performed catalytic interface.

Probing into the In-Situ Exsolution Mechanism of Metal Nanoparticles from Doped Ceria Host.

Exsolved nanoparticle catalysts have recently attracted broad research interest as they simultaneously combine the features of catalytic activity and chemical stability in various applications of energy conversion and storage. As the internal mechanism of in-situ exsolution is of prime significance for the optimization of its strategy, comprehensive research focused on the behaviors of in-situ segregation for metal (Mn, Fe, Co, Ni, Cu, Ag, Pt and Au)-substituted CeO2 is reported using first-principles calculations. An interesting link between the behaviors of metal growth from the ceria host and their microelectronic reconfigurations was established to understand the inherent attribute of metal self-regeneration, where a stair-stepping charge difference served as the inner driving force existing along the exsolving pathway, and the weak metal-coordinate associations synergistically facilitate the ceria's in-situ growth. We hope that these new insights provide a microscopic insight into the physics of in-situ exsolution to gain a guideline for the design of nanoparticle socketed catalysts from bottom to top.

Achieving Highly Efficient Carbon Dioxide Electrolysis by In Situ Construction of the Heterostructure.

The design of active cathode catalysts, with abundant active sites and outstanding catalytic activity for CO2 electroreduction, is important to promote the development of solid oxide electrolysis cells (SOECs). Herein, A-site-deficient perovskite oxide (La0.2Sr0.8)0.9Ti0.5Mn0.4Cu0.1O3-δ (LSTMC) is synthesized and studied as a promising cathode for SOECs. Cu nanoparticles can be rapidly and uniformly in situ-exsolved under reducing conditions. The heterostructure formed by the exsoluted Cu and LSTMC provides abundant active sites for the catalytic conversion of CO2 to CO. Combined with the remarkable oxygen-ion transport capacity of the LSTMC substrate, the specially designed Cu@LSTMC cathode exhibits a dramatically improved electrochemical performance. Furthermore, first-principles calculations proposed a mechanism for the adsorption and activation of CO2 by the heterostructure. Electrochemically, the Cu@LSTMC presents a high current density of 2.82 A cm-2 at 1.8 V and 800 °C, which is about 2.5 times higher than that of LSTM (1.09A cm-2).

Weakening the strong Fe-La interaction in A-site-deficient perovskite via Ni substitution to promote the thermocatalytic synthesis of carbon nanotubes from plastics.

The variation of metal-support interaction (MSI) plays a key role in the synthesis of carbon nanotubes (CNTs) based on chemical vapor deposition process. This work concentrates on weakening the interaction of Fe-La in an A-site-deficient perovskite (La0.8FeO3-δ) via Ni partial substitution. After reductive treatment, the catalysts were employed for thermocatalytic synthesis of CNTs from plastics. Following the structural, morphological and chemical changes, the catalytic activities of the reductive La0.8NixFe1-xO3-δ (H-LNxF1-x, x = 0, 0.15, 0.5, 0.85) were correlated with the degree of MSI. Compared with H-LF sample, the H-LN0.15F0.85 sample exhibited the highest catalytic activity, which was attributable to the highest surface coverage of metals as well as the synergistic effect of Fe and Ni species. The yield of CNTs produced from low density polyethylene was 1.44 g/gcatalyst over the H-LN0.15F0.85 sample, which was much higher than that over H-LF sample (0.38 g/gcatalyst).

Perovskite Chromite With In-Situ Assembled Ni-Co Nano-Alloys: A Potential Bifunctional Electrode Catalyst for Solid Oxide Cells.

Solid oxide fuel cell (SOFC) is an advanced electricity generation device with attractive fuel flexibility and conversion efficiency. As its reversed process, solid oxide electrolysis cell (SOEC) can efficiently electrolyze notorious CO2 to valuable chemical product such as CO, by utilizing renewable energy. To achieve long-term operation, the development of catalytically active electrode materials in both SOFC/SOEC modes is highly desirable, yet still challenging. In this research, an A-site deficient perovskite oxide (lanthanum chromite) decorated with in-situ exsolved Ni-Co nano-alloy has been fabricated and applied as a potential fuel electrode for both SOFC/SOEC. The influences of A-site non-stoichiometry and B-site dopant concentration on structural properties and in-situ exsolution process have been elaborately studied from various aspects. Diverse characterizations collectively confirm that the existence of A-site deficiency helps the formation of oxygen vacancies and stimulates the exsolution of B-site cations. In addition, the synergistic effect between the dopants of Co and Ni manipulates the reducibility and promotes carbon deposition resistance of the material. The electrolyte-supported SOFC with self-assembled Ni-Co nano-alloy electrode has shown maximum power densities of 329 mW/cm2 (in H2) and 258 mW/cm2 (in syngas, H2 + CO) at 850 °C, which are 50% better than those of the fuel cell with the exsolved Ni nanoparticles only. Also, the nano-alloy decorated electrode catalyst promotes a 30% increase in SOEC performance for CO2 electrolysis with prominently enhanced resistance against carbon deposition, suggesting the versatile functionality of the materials.

Vanadium-Doped Strontium Molybdate with Exsolved Ni Nanoparticles as Anode Material for Solid Oxide Fuel Cells.

Vanadium-doped strontium molybdate (SVM) has been investigated as a potential anode material for solid oxide fuel cells due to its high electronic conductivity of about 1000 S cm-1 at 800 °C in reducing atmospheres. In this work, NiO is introduced to SVM with the B-site excess design to induce in situ growth of Ni nanoparticles in the anodic operational conditions. The Ni particles are exsolved from the parent oxide phase as clearly demonstrated with various techniques including X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The exsolved Ni nanoparticles significantly boost the electrocatalytic activity toward fuel oxidation reaction, improving the peak power density by 160% from 0.21 to 0.56 W cm-2 at 800 °C when using H2 as the fuel, meanwhile reducing the total interfacial polarization resistance by 56% from 0.81 to 0.36 Ω cm2. The Ni-exsolved SVM anode also shows excellent catalytic activity toward H2S-containing and hydrocarbon fuels, providing peak power densities of 0.43, 0.36, and 0.22 W cm-2 at 800 °C for H2-50 ppm H2S, syngas, and ethanol, respectively. In addition, the cell with the Ni-exsolved SVM anode presents a stable power output, indicating that the Ni-SVM is a potential SOFC anode electrocatalyst for various fuels.

In Situ Observation of Nanoparticle Exsolution from Perovskite Oxides: From Atomic Scale Mechanistic Insight to Nanostructure Tailoring.

Understanding and controlling the formation of nanoparticles at the surface of functional oxide supports is critical for tuning activity and stability for catalytic and energy conversion applications. Here, we use a latest generation environmental transmission electron microscope to follow the exsolution of individual nanoparticles at the surface of perovskite oxides, with ultrahigh spatial and temporal resolution. Qualitative and quantitative analysis of the data reveals the atomic scale processes that underpin the formation of the socketed, strain-inducing interface that confers exsolved particles their exceptional stability and reactivity. This insight also enabled us to discover that the shape of exsolved particles can be controlled by changing the atmosphere in which exsolution is carried out, and additionally, this could also produce intriguing heterostructures consisting of metal-metal oxide coupled nanoparticles. Our results not only provide insight into the in situ formation of nanoparticles but also demonstrate the tailoring of nanostructures and nanointerfaces.

Reducing the Barrier Energy of Self-Reconstruction for Anchored Cobalt Nanoparticles as Highly Active Oxygen Evolution Electrocatalyst.

It is crucial for leaping forward renewable energy technology to develop highly active oxygen evolution reaction (OER) catalysts with fast OER kinetics, and the novel design of high-performance catalysts may come down to unveiling the origin of high catalytic behavior. Herein, a new class of heterogeneous OER electrocatalyst (metallic Co nanoparticles anchored on yttrium ruthenate pyrochlore oxide) is provided for securing fast OER kinetics. In situ X-ray absorption spectroscopy (in situ XAS) reveals that fast OER kinetics can be achieved by the harmonious catalytic synergy of a pyrochlore oxide support to Co nanoparticles. By the facile oxidation of yttrium (A-site) and ruthenium (B-site) cations, the pyrochlore oxide support helps to expel the electrons generated from the catalytic behavior of Co to the inner layers of the support, facilitating the electrostatic adsorption of OH- ions and reducing the barrier energy for the formation of CoOOH intermediates. This work affords the rational design of transition metal nanoparticles anchored on pyrochlore oxide heterogeneous catalysts and the fundamental insight of catalytic origin associated with self-reconstruction of OER electrocatalysts.

Highly Stable and Efficient Perovskite Ferrite Electrode for Symmetrical Solid Oxide Fuel Cells.

Here, we report a new perovskite oxide with formula Sm0.8Sr0.2Fe0.8Ti0.15Ru0.05O3-δ (SSFTR), which exhibits a great potential as a symmetrical electrode material with satisfying stability in both reducing and oxidizing environments. Moreover, SSFTR exhibits good redox and thermal cycle stability. The electrolyte-supported (Sm0.2Ce0.8O1.9, SDC) symmetrical cell with SSFTR electrodes possesses a peak power density of 271 mW·cm-2 at 800 °C in wet H2. Moreover, the peak power density is remarkably improved to 417 mW·cm-2 when applying A-site-deficient perovskite oxide Sm0.7Sr0.2Fe0.8Ti0.15Ru0.05O3-δ as the symmetrical electrode, benifiting by the in situ-exsolved Ru nanoparticles with excellent electrocatalytic activity, since A-site deficiency can provide additional driving force for the exsolution of B-site cations upon reduction. As an ingenious approach, this exsolution of electrocatalytically active nanoparticles on the surface of electrode may be applicable to the development of other excellent performance electrodes for symmetrical SOFCs and other electrochemical systems.