FeNbO4-based oxide cathode for steam electrolysis

Density Functional Theory Study of Monoclinic FeNbO4: Bulk Properties and Water Dissociation at the (010), (011), (110), and (111) Surfaces

“…20,21 To improve the stability of the cathode, suitable ABO 3 perovskites are being explored as replacements for the Ni metal, or other metals are introduced to form more stable alloys with Ni. 18−20 Interestingly, both m-and o-FeNbO 4 have shown potential as replacement materials for the Ni metal, owing to their proven catalytic conductivity and properties as cathodes in SOEC, 5 where the splitting of water vapor takes place. However, no computational studies have been carried out on the surface properties and reactions with gases, especially the water vapor splitting, of the m-and o-FeNbO 4 phases.…”

“…In recent years, research has intensified into the development of ABO 4 -type oxides, including iron niobate (FeNbO 4 ). − So far, three different FeNbO 4 phases have been reported, i.e., the monoclinic wolframite-type structure (m-FeNbO 4 , space group P 2/c), the orthorhombic α-PbO 2 -type structure (o-FeNbO 4 , space group P 2/c), and the rutile-type structure (r-FeNbO 4 , space group P 4 2 /mnm) . Under ambient conditions, m-FeNbO 4 has the most stable structure, , where both Fe 3+ and Nb 5+ are coordinated by six oxygen ions, forming stable octahedra.…”

“…Out of the three iron niobate phases, m- and o-FeNbO 4 are promising materials for many applications. For example, m-FeNbO 4 has excellent potential as a gas sensor material, − owing to its good electrical properties due to similar radii but different valence states of the Fe and Nb cations, whereas o-FeNbO 4 has been investigated as a photodetector for solar energy conversion devices − and an anode material in solid oxide fuel cells (SOFC). , Conventionally, nickel metal particle-based materials have been used widely in the cathodes of solid oxide electrolysis cells (SOEC) owing to their significant advantages, i.e., low cost, good catalytic, and high electronic conductivity, − although they also have disadvantages, such as tendency to coarsening and depletion of Ni particles. , To improve the stability of the cathode, suitable ABO 3 perovskites are being explored as replacements for the Ni metal, or other metals are introduced to form more stable alloys with Ni. − Interestingly, both m- and o-FeNbO 4 have shown potential as replacement materials for the Ni metal, owing to their proven catalytic conductivity and properties as cathodes in SOEC, where the splitting of water vapor takes place.…”

Iron-based electrode materials for solid oxide fuel cells and electrolysers

“…The current density of the electrolysis cell with the (La0.2Sr0.8)0.9Ti0.9Fe0.1O3--GDC electrodes reached approximately 150 mA•cm −2 at 1.6 V at 800 o C, higher than 120 mA•cm −2 for the bare (La0.2Sr0.8)0.9TiO3- -SDC electrodes, because of the reversible growth of Fe 0 particles on the surface in the former 193 . The improved electrocatalysis of Fe 0 over oxide cathode could indicate that the intrinsic exsolution of Fe 0 under cathodic current 194 could induce the "smart" behavior of ferrite perovskite that maintains high electrocatalysis and stability under a cathodic bias for electrolysis.…”

Oxygen diffusion in the orthorhombic FeNbO4 material: a computational study

“…16,19 In recent years, both m-and o-FeNbO 4 materials have been explored for energy storage and conversion applications. [20][21][22] Interestingly, both m-and o-FeNbO 4 have shown potential as a replacement material for the Ni metal in the cathodes of solid oxide electrolysis cells (SOEC) 21,22 and the anodes of solid oxide fuel cells (SOFC), 20 where the splitting of water vapour takes place, although o-FeNbO 4 is more suitable in electrodes than m-FeNbO 4 . It has been reported that, when m-FeNbO 4 is used as anode in SOFC, there is a clear weight loss during its operation, 20 caused by the ordering within the m-FeNbO 4 system, where Fe 3+ and Nb 5+ layers are distributed alternately through the structure.…”