Structural stability of anhydrous proton conducting SrZr0.9Er0.1O3−δ perovskite ceramic vs. protonation/deprotonation cycling: Neutron diffraction and Raman studies

Abstract

Structural stability of anhydrous proton conducting SrZr0.9Er0.1O3-δ perovskite ceramic vs. protonation/deprotonation cycling: neutron diffraction and Raman studies Running title: Structural stability of anhydrous SrZr0.9Er0.1O3-δ proton conducting perovskite

Vibrational study of the various forms of (solvated or unsolvated) mobile proton in materials for storage and production systems based on the hydrogen vector. Advantages, limitations and open questions

“…The comparison of the signal of a compound before and after drying at ~ 400K makes it possible to differentiate the contributions of bulk and surface protons [11]. The use of perfectly densified single crystals or ceramics -and not powder -guarantees the quality of the results, whether for diffraction or neutron spectroscopy [13][14][15]. Due to its very polarizing nature, the proton species form dipoles and, therefore, infrared spectroscopy is the most effective method to study protonic species [3,10,16,17].…”

“…Figure 3 compares the Raman spectra of a dense ceramic of SrZr 0.9 Er 0.1 O 3-δ as a function of heat treatment sequence cycles (from RT to 900°C under ultra-high vacuum, i.e. de-protonation) and autoclave protonation (500°C, 40 bar H 2 O, several days to protonate to core) [14]. The bulk proton content is measured by TGA, elastic neutron scattering and neutron diffraction [10,11].…”

Proton conductors and their applications: A tentative historical overview of the early researches

“…We will consider more specifically neutron scattering and frequency dependent conductivity. The number of papers based on neutron scattering (diffraction: 357; quasielastic: 79 and inelastic: 39) is limited despite the very efficiency of neutron techniques to understand the structure and dynamics of H-containing compounds (see refs [1,94,117,131,137,260,268,[278][279][280][281] and further references).…”

“…[130][131][132]137,164,[182][183][184][185][186][187][188][255][256][257][258][259][260]268,[279][280][281]331,332,. Perchlorates [344,346,365,366], beta aluminas [349][350][351]373,374], clays [352], Nafion® [353,390,391], HUP [354,359], CsHsO 4 [350,358,360], M 3 H(SO 4 ) 2 [368], hydrates [362,363,372,388], hydroxides [367,369], hydrogen-containing metals and hydrides…”

“…based compounds such as apatite or perovskites [127][128][129][130][131][132][133][134][135]137,138,[212][213][214][215][216][217][218][219]. Perovskites have received an increasing attention since the works of Forrat et al and then Iwahara et al[1,50,57,213- 225] Most of the recent works deal with technological issues (preparation, sintering, compatibility with substrate, electrodes, stability/ageing, etc.)…”