Synthesis and characterisation of Sr4Fe3-xCrxO10-δ: Stabilisation of n=3 Ruddlesden-Popper phases through Cr doping

DOI: 10.1016/j.jssc.2020.121372

Authors: A. Jarvis (University of Birmingham) , F. J. Berry (University of Birmingham) , J. F. Marco (Instituto de Química Física “Rocasolano”, CSIC) , M. Sanchez-Arenillas (Instituto de Química Física “Rocasolano”, CSIC) , G. Cibin (Diamond Light Source) , O. Clemens (Technical University Darmstadt; Karlsruhe Institute of Technology) , P. R. Slater (University of Birmingham)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Solid State Chemistry

State: Published (Approved)
Published: April 2020

Abstract: Ruddlesden-Popper type compounds have the general formula, An+1MnO3n+1±x (typically A is a rare earth, alkaline earth, M is a transition metal), and are constructed of perovskite-type layers separated by rock salt type blocks. While n = 1, 2 phases are typically straightforward to prepare, the synthesis of higher order (n > 2) systems is difficult. In this paper we show that chromate (CrO42−) doping can be exploited to stabilise new n = 3 Ruddlesden-Popper systems, Sr4Fe3-xCrxO10-δ: without chromate doping, a mixture of the n = 2 phase Sr3Fe2O7-x and perovskite-type SrFeO3-x is obtained. This can be explained by the stabilisation of the central perovskite building block by chromate incorporation, similar to prior work on sulfate and carbonate doping in this system. The structure, and Fe/Cr oxidation states were evaluated by X-ray diffraction, 57Fe Mössbauer spectroscopy and X-ray absorption spectroscopy supporting the incorporation of Cr as CrO42−. In order to examine the potential of these new systems for use as a SOFC cathode material, conductivity studies were carried out, which showed semiconducting behaviour with slightly higher conductivities than the sulfate doped counterparts.

Journal Keywords: Solid oxide fuel cell; Cathode; Ruddlesden-Popper; Chromate

Diamond Keywords: Fuel Cells; Semiconductors

Subject Areas: Chemistry, Materials


Instruments: B18-Core EXAFS

Added On: 21/04/2020 10:05

Discipline Tags:

Earth Sciences & Environment Sustainable Energy Systems Energy Climate Change Physical Chemistry Chemistry Materials Science Perovskites Metallurgy

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)