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The in situ exsolution technique of nanoparticles has brought new opportunities for the utilization of perovskite‐based catalysts in solid oxide cells. However, the lack of control over the structural evolution of host perovskites during the promotion of exsolution has restricted the architectural exploitation of exsolution‐facilitated perovskites. In this study, we strategically broke the long‐standing trade‐off phenomenon between promoted exsolution and suppressed phase transition via B‐site supplement, thus broadening the scope of exsolution‐facilitated perovskite materials. Using carbon dioxide electrolysis as an illustrative case study, we demonstrate that the catalytic activity and stability of perovskites with exsolved nanoparticles (P‐eNs) can be selectively enhanced by regulating the explicit phase of host perovskites, accentuating the critical role of the architectures of perovskite scaffold in catalytic reactions occurring on P‐eNs. The concept demonstrated could potentially pave the way for designing the advanced exsolution‐facilitated P‐eNs materials and unveiling a wide range of catalytic chemistry taking place on P‐eNs. [ABSTRACT FROM AUTHOR]

The alkaline earth element- and cobalt-free Ni(Mn1/3Cr2/3)2O4 (NMC) spinel is adopted to form composite electrodes with an oxygen ion conductive phase for symmetrical solid oxide cells and its applicability is successfully demonstrated in both solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) modes. In a H2 or CO–CO2 atmosphere, NMC decomposes to Ni and spinel, but would quickly recover to NMC in air or pure CO2. Both NMC and NMC–Gd0.1Ce0.9O2−δ (NMC–GDC) composite electrodes reveal a high redox resistance and fast recovery, which originated from the significant difference in Gibbs free energy when NMC is subjected to reducing and oxidizing atmospheres. In SOFC mode at 800 °C, the anode supported and symmetrical cells with the NMC–GDC electrode achieve peak power densities of 1293 and 416 mW cm−2, respectively. With an applied current density of 400 mA cm−2 at 750 °C in SOFC mode, the working voltage of the symmetrical cell with the NMC–GDC electrode showed no evident decline over 96 h. In SOFC mode and under pure CO2 in the cathode, the symmetrical cell working in SOEC mode showed a faradaic efficiency of over 96% at 700–850 °C and an electrolysis current density of 2320 mA cm−2 at 850 °C with an applied voltage of 2 V. Furthermore, the applied voltage decreased from 1.507 V to 1.407 V over a 72 h running time under a static current density of 800 mA cm−2 at 800 °C. The nickel exsolution in a reduction atmosphere and the abundant transition metal element centered octahedra ensure the multi-functionality of NMC. The NMC spinel-based electrode demonstrates an extraordinary redox resistance and running stability, and it is anticipated to play a pivotal role in the future exploration of novel and stable electrodes for solid oxide cells. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 (CO2RR) is a versatile method that is capable of simultaneously reduce CO2 emission and produce valuable fuels and chemicals. However, its application is hindered by the lack of cost‐effective catalysts and significant overpotential requirement. In this work, we report a low‐cost and surfactant/capping agent free method to synthesize cubic Cu2O−SnO2 core‐shell electrocatalyst, whose thickness can be easily controlled by the content of tin precursor. The optimized Cu2O−SnO2 catalyst with a 5 nm‐thick shell achieved over 90 % faradaic efficiency towards CO at a low overpotential of 390 mV, which is comparable to some of the noble metal catalysts. The catalyst also exhibited good stability over 18 hours of test at −0.6 V vs. RHE in 0.5 M KHCO3 electrolyte. This work provides a widely applicable strategy for developing a low‐cost electrocatalyst for CO2 conversion. [ABSTRACT FROM AUTHOR]

In LaNbO 4 , Sm, Gd and Yb were investigated as substitutes to enhance its ion conductivity, for its application in solid oxide fuel cell. La 0.9 M 0.1 NbO 4 (M = Sm, Gd, Yb) was prepared via a solid–state reaction route and single phase was attained by calcining the constituent oxides at 1200 °C for 5 h. The total conductivity of LaNbO 4 was increased by partly replaced La with Sm, Gd and Yb, due to the muti-valences of the substitutions. The highest conductivity (1.76 × 10 −4 S cm −1 ) was achieved for La 0.9 Sm 0.1 NbO 4 at 800 °C in wet air, more than one order higher compared to that of LaNbO 4 . The introduction of Sm, Gd or Yb also slightly increased the ion transport number of LaNbO 4 , indicating that the increase of the total conductivity was mainly contributed by the enhanced ion conductivity, which was beneficial for its application as a pure ion conductor. [ABSTRACT FROM AUTHOR]

Hydration properties and electrical characteristics of the hightemperature proton conductor La27(W0.85Nb0.15)5O55.5-δ are investigated by means of thermogravimetry, impedance spectroscopy, and the electromotive force (EMF) method as a function of temperature, water vapor, and oxygen partial pressures, as well as isotope exchange measurements in order to elucidate the mechanism and thermodynamics of protons formation and transport. The highest proton conductivity, 1.3 3 10-3 S/cm, is achieved at 700°C in wet O2. Proton selfdiffusion coefficients are estimated from thermogravimetric measurements of hydration and conductivity data. Comparison of the conductivity characteristics between nominally pure and Nb-substituted materials reveals that the ionic conductivity increases and the activation energy decreases with Nb doping. These differences are discussed to reflect changes in the structure promoting ionic transport rather than changing the concentration of defects to any large extent. [ABSTRACT FROM AUTHOR]

Hydration properties and electrical characteristics of the hightemperature proton conductor La27(W0.85Nb0.15)5O55.5-δ are investigated by means of thermogravimetry, impedance spectroscopy, and the electromotive force (EMF) method as a function of temperature, water vapor, and oxygen partial pressures, as well as isotope exchange measurements in order to elucidate the mechanism and thermodynamics of protons formation and transport. The highest proton conductivity, 1.3 3 10-3 S/cm, is achieved at 700°C in wet O2. Proton selfdiffusion coefficients are estimated from thermogravimetric measurements of hydration and conductivity data. Comparison of the conductivity characteristics between nominally pure and Nb-substituted materials reveals that the ionic conductivity increases and the activation energy decreases with Nb doping. These differences are discussed to reflect changes in the structure promoting ionic transport rather than changing the concentration of defects to any large extent. [ABSTRACT FROM AUTHOR]

The effect of addition of molybdenum in Fe Cr Mn based alloy on the chromium deposition and poisoning of LSM cathodes is investigated at 800 °C by electrochemical impedance spectroscopy and microstructure analysis. The Fe Cr Mn Mo ferrite stainless steel metallic interconnect shows much less Cr deposition and poisoning on the LSM cathodes as compared with the Fe Cr Mn alloy. The addition of Mo into the alloy suppressed Cr evaporation from interconnects, decreased the degradation of cathode performance caused by Cr. According to SEM results, MoO 3 and MnMoO 4 is observed at the depositional area. The segregated MnO from LSM cathode can act as a nuclei agent, and react with vaporized Mo to form Mo-contained oxide particles, which will not inhibit the oxygen reduction reactions in the three phase boundary (TPB). As a result, suitable addition of Mo into the interconnect alloy can effectively alleviate the Cr poisoning of the LSM cathode. [ABSTRACT FROM AUTHOR]

To increase corrosion resistance of gadolinium-doped cerium oxide (GDC) electrolytes for direct carbon solid oxide fuel cells with liquid Sb anodes, GDC-based electrolytes with Fe 2 O 3 addition of 1 (GDCF-1), 2 (GDCF-2) and 3 (GDCF-3) mol.% have been prepared and evaluated chemically and electrochemically in contact with liquid Sb and Sb 2 O 3 at 750 °C for 100 h. The results show that Fe 2 O 3 addition significantly increases the resistance of the electrolytes to the chemical corrosion by liquid Sb, and GDCF-2 demonstrates the highest resistance with a corrosion affected thickness of about 60 μm, which is smaller than 1/8 of that of GDC. What's more, the affected thickness is only about 4 μm for GDCF-2 in contact with liquid Sb 2 O 3. Under a current density of 100 mA cm−2 with liquid Sb as anode, the cell voltage almost increases linearly and cell ohmic resistance decreases in the 100 h's operation. The performance promotion is resulted from the reduction of GDCF-2 thickness caused by liquid Sb/Sb 2 O 3 corrosion, but the total thickness reduction is about 200 μm, which is only 2/5 of that of GDC. • Fe 2 O 3 addition enhances GDC's resistance to hot corrosion by liquid Sb and Sb 2 O 3. • GDC with 2 mol.% Fe 2 O 3 demonstrates highest resistance to liquid Sb corrosion. • GDC with 2 mol.% Fe 2 O 3 shows a corrosion rate smaller than 1/8 of that of GDC. • Cell ohmic impedance is proved to be a feasible indicator of corrosion degree. [ABSTRACT FROM AUTHOR]

A newly developed interconnect alloy for solid oxide fuel cells, containing Fe, Cr, Mn and Mo as well as other minor elements and designated as FeCM, is investigated on its poisoning effect on (La 0.8 Sr 0.2 ) 0.95 MnO 3−δ (LSM) cathode by electrochemical impedance spectroscopy and microstructure observation. Compared with commercial SUS430 stainless steel, which is usually used as a essential interconnect in the SOFCs stacks, the FeCM alloy as the interconnect reduces the ohmic of the cell (R Ω ) and polarization resistance of the cathode (R P ) and increases the electrochemical performance of the cathode. At 850 °C the R Ω remains almost unchanged at a level slightly above 2.0 Ω cm 2 and the R P decreases from 5.76 to 1.68 Ω cm 2 within 20 h, while the cathode potential at 200 mA min −1 is virtually stabilized at below 1.0 V and the overpotential is decreased from 0.43 to 0.16 V. Based on the evidence of a narrower oxide deposition zone on the electrolyte surface near the cathode and a deposition-free cathode/electrolyte interface, this improvement is attributed to the reduced degree of volatilization of oxide scale formed on the surface of the FeCM alloy. [ABSTRACT FROM AUTHOR]

The in situ exsolution technique of nanoparticles has brought new opportunities for the utilization of perovskite-based catalysts in solid oxide cells. However, the lack of control over the structural evolution of host perovskites during the promotion of exsolution has restricted the architectural exploitation of exsolution-facilitated perovskites. In this study, we strategically broke the long-standing trade-off phenomenon between promoted exsolution and suppressed phase transition via B-site supplement, thus broadening the scope of exsolution-facilitated perovskite materials. Using carbon dioxide electrolysis as an illustrative case study, we demonstrate that the catalytic activity and stability of perovskites with exsolved nanoparticles (P-eNs) can be selectively enhanced by regulating the explicit phase of host perovskites, accentuating the critical role of the architectures of perovskite scaffold in catalytic reactions occurring on P-eNs. The concept demonstrated could potentially pave the way for designing the advanced exsolution-facilitated P-eNs materials and unveiling a wide range of catalytic chemistry taking place on P-eNs., (© 2023 The Authors. Published by Wiley-VCH GmbH.)