Surface Protonic Conduction on Oxide Ceramics: Mechanism, Materials, and Method for Characterization

Abstract

ex 2 p is the actual water partial pressure kept at about 0.032 atm, indicates the relative humidity. Reproduced with permission. [55] Copyright 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. b) Total conductivities of TiO 2 samples with predominance of different crystal facets of {001} (T001), {100} (T100) and {101} (T101) under wet air ( H O 2 p = 0.026 atm). Reproduced under the terms of the CC-BY license.

Direct Operando Visualization of Metal Support Interactions Induced by Hydrogen Spillover During CO2 Hydrogenation

“…The operando EELS measurements show that hydrogen spillover under hydrogenation conditions was not limited to the nanofiber interfacing with the Ni NP, rather hydrogen was found to traverse the complex mesoporous network over tens of nanometers to reduce the surface of neighboring CeO 2 nanofibers owed to CeO 2 proton conductivity. [ 33 ] Interestingly, the depth of the reduced surface within the individual CeO 2 fibers is consistent (≈2 nm), however the abundance in Ce 3+ at the surface of each nanofiber increases significantly with proximity to the NP. Of the four fibers within the field of view, Ce 3+ shell abundance increases from 12% for the nanofiber furthest away from Ni, to 17%, 28%, and finally 45% for the nanofiber supporting the Ni NP.…”

Fluorite-based proton conducting oxides: structures, materials and applications

“…The progress of some other materials of lanthanide ziconates, stannates and titanates, and La 2 (Nb 1− x M x ) 2 O 7− δ (M = Y, Yb) – a recently discovered new proton conductor – was also summarized. Although nanocrystalline or porous ZrO 2 and CeO 2 are also known for their surface proton conduction at low temperature, detailed information can be found in a recent review paper, 17 and only the volume transport is discussed in this review paper.…”