Determination of proton- and oxide ion tracer diffusion in lanthanum tungstate (La/W = 5.6) by means of ToF-SIMS

文献信息

发布日期 2012-08-30

DOI 10.1039/C2CP42278F

影响因子 3.676

作者

Ragnhild Hancke, Sarah Fearn, John A. Kilner, Reidar Haugsrud

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摘要

Tracer diffusion of protons and oxide ions, as well as chemical diffusion of water, have been determined for the high temperature proton conductor lanthanum tungstate by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS). The oxygen tracer diffusion and surface exchange coefficients, and , were measured after exchange anneals in water vapor enriched in H218O between 350 and 620 °C, and the apparent activation energies were 176 and 82 kJ mol−1, respectively. The hydrogen tracer diffusion coefficient () was measured between 220 and 320 °C after exchange anneals in D2O-containing atmospheres, and the apparent activation energy was 63 kJ mol−1. The extracted agrees with the results of transient conductivity- and TG-measurements. Chemical diffusion and surface exchange coefficients, and , were measured at 250 and 400 °C, and the result confirms that the material is hydrated by ambipolar sluggish transport of protons and oxide ions. The surface exchange coefficients were compared to the result of TG relaxation, suggesting that access to oxygen vacancies limits the overall surface exchange reaction under incorporation of water and oxygen.

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来源期刊

Physical Chemistry Chemical Physics

CiteScore: 5.5

自引率: 10.3%

年发文量: 3036

Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions. The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.