title: Platinum uptake and Ba2CePtO6 formation during in situ BaCe(1-x)M(x)O(3-δ) (M = La, In) formation.
abstract: We report the formation, structures, temperature-dependent phase transitions, and high-temperature reactivity of the potential proton and oxide ion conductors BaCe(1-x)M(x)O3 (M(3+) = In(3+), La(3+)). The present in situ diffraction studies show oxidative platinum uptake at temperatures as low as 950 °C into BaCeO3, forming the cubic Ba2CePtO6 double perovskite. The transient B-site double perovskite expels platinum at around 1200-1250 °C. Platinum oxidation via BaCeO3 is investigated by in situ powder X-ray and neutron diffraction experiments in various atmospheres. Doped BaCe(1-x)M(x)O3 phases show the formation of Ba2CePtO6 without incorporating the M(3+) dopant. Oxidative platinum uptake is also observed during the synthesis of BaCeO3 on platinum metal. We report the reaction pathway for the low-temperature oxidative formation of Ba2CePtO6 and the subsequent liberation of platinum for the barium cerate system. The findings are supported by ambient-temperature X-ray diffraction, in situ powder X-ray, and powder neutron diffraction as well as XPS.
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, MB R3T 2N2, Canada.
authors.forename: Joey A
authors.initials: JA
authors.lastname: Lussier
authors.forename: Shahid P
authors.initials: SP
authors.lastname: Shafi
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Donaberger
authors.forename: Mario
authors.initials: M
authors.lastname: Bieringer