Title: Exsolution and integration of nanosized SMART catalysts for next generation SOFC anodes
Authors : Burnat, Dariusz
Holzer, Lorenz
Franken, Tanja
Mai, Andreas
Heel, Andre
Proceedings: Proceedings of 13th European SOFC & SOE Forum 2018
Conference details: 13th European SOFC & SOE Forum 2018, Lucerne, 3-6 July 2018
Issue Date: 5-Jul-2018
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Abstract)
Language : English
Subjects : Anodes; Perovskite; Smart Material; SOFC
Subject (DDC) : 621.3: Electrical engineering and electronics
Abstract: La-doped strontium titanate (LST) materials are widely recognized among other alternative anodes as good electronic conductors with high tolerance to redox cycles, but with insufficient catalytic activity. However, doping of LST with quasi-stable metal ions (e.g. Ni, Co) allows a selective exsolution of these metals from the bulk onto the materials surface and thus increasing the catalytic activity. Previously we have demonstrated our SMART material concept with selfregeneration effect, in which nano-sized nickel catalyst is repeatedly exsolved from and incorporated back into the La0.2.Sr0.7Ti0.95Ni0.05O3-d (LSTN) perovskite host structure. Nickel nanoparticles are exsolved from LST at SOFC anode conditions and nickel is reincorporated at high pO2, during a redox cycle. This turns redox cycles - the weakness of conventional Ni/YSZ anodes - into an advantage and regenerates the material. The authors present recent advances of the SMART material catalysts based on LSTN. We demonstrate that upon harsh heat treatment (T = 1200°C) depending on the location and site at least three types of nickel particles being generated LSTN: a) fine particles with presumably high catalytic activity (dp < 15 nm) b) large particles located on grain facets up to 150 nm c) large particles located on grain boundaries above 100 nm. Also at 1200°C a significant growth of nickel crystallites can be observed, which is however reversed by redox cycling at T = 900°C. Even large particles (dp >150 nm), generated on the facets of grains are reversibly incorporated into the LSTN host matrix (Fig. 1), while those large ones located at the grain boundaries underwent an oxidation to NiO. Temperature programmed reduction has proven unchanged REDOX reversibility of LSTN materials upon 9 redox cycles a temperature of 900°C, suggesting catalytic reversibility.
Further description : B1104
Departement: School of Engineering
Organisational Unit: Institute of Computational Physics (ICP)
Institute of Materials and Process Engineering (IMPE)
Publication type: Conference Paper
URI: https://digitalcollection.zhaw.ch/handle/11475/8935
Appears in Collections:Publikationen School of Engineering

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