Structural, Magnetic and Catalytic Properties of a New Vacancy Ordered Perovskite Type Barium Cobaltate BaCoO2.67.
A new vacancy ordered, anion deficient perovskite modification with composition of BaCoO2.67 (Ba3 Co3 O8 □1 ) has been prepared via a two-step heating process. Combined Rietveld analysis of neutron and X-ray powder diffraction data shows a novel ordering of oxygen vacancies not known before for barium cobaltates. A combination of neutron powder diffraction, magnetic measurements, and density functional theory (DFT) studies confirms G-type antiferromagnetic ordering. From impedance measurements, the electronic conductivity of the order of 10-4  S cm-1 is determined. Remarkably, the bifunctional catalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is found to be comparable to that of Ba0.5 Sr0.5 Co0.8 Fe0.2 O3-y , confirming that charge-ordered anion deficient non-cubic perovskites can be highly efficient catalysts.
['Iqbal Waidha|Aamir|A|http://orcid.org/0000-0002-4554-8470', 'Khatoon Siddiqui|Humera|H|', 'Ikeda|Yuji|Y|', 'Lepple|Maren|M|', 'Vasala|Sami|S|', 'Donzelli|Manuel|M|', 'Fortes|A D|AD|', 'Slater|Peter|P|', 'Grabowski|Blazej|B|', 'Kramm|Ulrike I|UI|http://orcid.org/0000-0002-0884-1459', 'Clemens|Oliver|O|http://orcid.org/0000-0002-0860-0911']
magnetism perovskite ab initio calculations bifunctional catalyst neutron diffraction