An innovative efficient oxygen electrode for SOFC: Pr 6 O 11 infiltrated into Gd-doped ceria backbone

Abstract

The praseodymium oxide, Pr6O11, is regarded as a potential electrocatalyst for the oxygen reduction reaction. Its mixed conductivity properties are characterized. At 600 °C the oxygen diffusion coefficient value is as high as 3.4 × 10 −8 cm 2 s −1 , and that of the surface exchange coefficient is 5.4 × 10 −7 cm s −1 , which supposes excellent electrocatalytic properties. The measured electronic conductivity is high enough for using this material as a SOFC cathode. Herein, praseodymium nitrate is infiltrated into Gd doped ceria (GDC) backbone and fired at 600 °C to form a composite oxygen electrode Pr6O11/GDC. Electrochemical measurements show very low polarization resistance, Rp = 0.028 Ω cm 2 at 600 °C. A single cell made of a commercial Ni-YSZ/YSZ half cell and of the infiltrated cathode is able to deliver a maximum power density of 825 mW cm −2 at 600 °C. Ageing of this cell for 840 h, at 600 °C and 0.5 A cm −2 , shows a degradation rate lower than 1%.

Enhancing oxygen permeation through Fe2NiO4–Ce0.8Tb0.2O2−δcomposite membranes using porous layers activated with Pr6O11nanoparticles

“…However, more research is needed to explain this observation. Furthermore, the exchange rate of NFO-CTO is increased by more than one order of magnitude after activation with Pr 6 O 11 nanoparticles ( Figure 5), in line with permeation results (Figure 3) and previous reports on SOFC cathodes [27][28][29]44 . With regard to the activation energies, it is observed a significant difference for the Pr 6 O 11activated NFO-CTO sample with a diminution in the values…”

“…In addition, the contribution of HF processes decreases, and this can be assigned to transport properties of Pr 6 O 11 oxide covering the NFO-CTO electrode surface, which may favor the surface transport of both oxygen species and electron holes 27,28 . Furthermore, Pr 6 O 11 possesses relatively high electronic conductivity and improve the oxygen surface processes 27,28,44 and the surface exchange rate at the tested temperatures ( Figure 5). The influence of different atmospheres on the electrochemical performance was further studied.…”

“…In recent years, infiltration of active components into porous scaffolds has been gaining increased attention to enhance the performance of SOFC electrodes 26 , as previously practiced to improve the performance of La 0.8 Sr 0.2 MnO 3- -Ce 0.8 Gd 0.2 O 2- cathodes 27 . Following previous studies of modification of SOFC cathodes by infiltration with praseodymium oxide (Pr 6 O 11 ) nanoparticles [27][28][29] , the present work focuses on enhancing the oxygen permeation rate of Fe 2 NiO 4 -Ce 0.8 Tb 0.2 O 2-(NFO-CTO) dual-phase composite membranes. This is achieved by activating the porous NFO-CTO layers with Pr 6 O 11 .-coated on both membrane sides.…”

Metal‐Supported Solid Oxide Electrolysis Cell with Significantly Enhanced Catalysis

“…As a starting point, cells with a single catalyst, namely La 0.15 Sr 0.85 MnO 3‐δ (LSM), La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3‐δ (LSCF), or Pr 6 O 11 , on the oxygen electrode side and Sm 0.2 Ce 0.8 O 2‐δ (SDC) mixed with 20 vol% Ni (SDCN20) on the hydrogen electrode side were fabricated. Three infiltration cycles were used for both oxygen and hydrogen electrodes.…”

“…By infiltrating catalysts using nitrate precursors with sequential calcination steps, continuous blankets of the catalyst were formed on the interior surface of the SCSZ backbone. Figure 1d [74][75][76][77] on the oxygen electrode side and Sm 0.2 Ce 0.8 O 2-δ (SDC) mixed with 20 vol% Ni (SDCN20) on the hydrogen electrode side were fabricated. Three infiltration cycles were used for both oxygen and hydrogen electrodes.…”