In Situ Tailored Nickel Nano-Catalyst Layer for Internal Reforming Hydrocarbon Fueled SOFCs

Abstract

Conventional Ni cermet anodes suffer from carbon deposition when they are directly used with hydrocarbon fuels due to the negative effects of pyrolysis and Boudouard reactions. In this work, the use of a non-stoichiometric perovskite, La0.8Ce0.1Ni0.4Ti0.6O3, as a reforming layer in reducing atmospheres led to the surface being highly populated with homogeneously exsolved Ni nano particles. This catalyst layer was applied to Ni-GDC anode supported and ScSZ electrolyte supported cells to prevent carbon deposition and to stabilize operation with dry methane. The catalyst layer showed both excellent attachment to the Ni-GDC anode and resistance to carbon deposition. The performance of the Ni–GDC anode-supported cells with the catalyst layer was about 1.1 W/cm2 in hydrogen fuel which is similar to that seen without the use of a catalyst layer. For the ScSZ electrolyte supported cells, the catalyst layer improved the power density and stability when in operation with dry methane.

Smart material concept: reversible microstructural self-regeneration for catalytic applications

“…21 To investigate this, LSTN compositions with various A-site decient stoichiometries and with varying surface conditions were investigated with respect to the resulting morphology and microstructure aer a reduction for 2 h at 900 C in 5 vol% H 2 in Ar (Fig. 7).…”

“…Literature survey reports single phase LSTN compositions with Ni contents as high as 25 at%, which suggests that also higher contents of surface Ni could be obtained. 6 Microstructural reversibility and thermal stability of the Ni phase Neagu et al 5,21 have shown that exsolution of a metallic phase such as nickel from a titanate perovskite host matrix is possible and that this concept can be used to prepare nanoparticles on the surface. However, it was not shown that this material effect could be used in a reversible manner by reintegrating the metallic phase in the host titanate and to apply this effect repetitively, and on purpose, for microstructural and catalytic self-regeneration.…”

The Investigation of Current Collector Layers and Design Modification of SOFCRoll Cell with LCNT-Based Electrode

“…The recent work incorporated an alternative fuel electrode based on A-site deficient, nickel-doped perovskite La 0.43 Ca 0.37 Ni 0.06 Ti 0.94 O 3-γ into the SOFCRoll structure [4]. The LCNT is perovskite able to exsolve Ni nanoparticles and proved to be an excellent fuel electrode in high-temperature solid-oxide fuel cells (SOFC) [5]. For cell production, all tapes were cast on each other by sequential casting and co-sintered at 1350 °C [4].…”

Nonreducing Ambient Atmosphere: Pulsed Electric Current Treatment of Co/Ni Doped Perovskite Oxides to Achieve Exsolution Enhanced Electrochemical Performance

“…This is achieved by applying reducing conditions and energy to allow NPs to spontaneously exsolve from the substrate oxides and load on the surface. This method not only retains the bulk phase information on the substrate but also exsolves the NPs on the substrate oxides, thereby enhancing the interface connection between the NPs and the substrate surface, the exsolved arrangement reduces the likelihood of growth and agglomeration. − However, the traditional high-temperature vapor phase reduction (HTVPR) process requires sufficient reduction time (10–72 h) and a high temperature (500–1300 °C) under a reducing atmosphere (such as H 2 , CO, and CH 4 ). − The vapor-phase reaction process requires the gas to undergo diffusion at the three-phase interface for an extended period, and the high-temperature treatment enhances the gas diffusion of the relatively stable reducing atmosphere, thereby increasing the touching ratio between the gas and B-site metal ions. In addition, it is necessary to maintain a continuous supply of reducing atmosphere throughout the experimental process and continuous reaction to promote the exsolution of B-site ions to form NPs .…”