4 years ago

On Hydride Diffusion in Transition Metal Perovskite Oxyhydrides Investigated via Deuterium Exchange

On Hydride Diffusion in Transition Metal Perovskite Oxyhydrides Investigated via Deuterium Exchange
Ayako Konishi, Hiroshi Kageyama, Takahide Nakashima, Yoji Kobayashi, Ya Tang, Cédric Tassel, Takafumi Yamamoto, Akihide Kuwabara, Kazuki Shitara
Perovskite oxyhydrides may find diverse applications, ranging from catalysis, topochemical synthesis to solid state ionics, but the understanding of their hydride transport behavior has remained limited. Here, gaseous hydrogen exchange and release experiments were analyzed using the Kissinger method to estimate the activation energy (Ea) for H/D exchange and H2 release in BaTiO3–xHx (x = 0.35–0.60) and LaSrCoO3H0.70. It is revealed that, for each BaTiO3–xHx at a given hydride concentration (x), both H/D exchange and H2 release experiments provide similar Ea values. For BaTiO3–xHx with different x, the obtained Ea values significantly decrease with increasing x until around 0.4; beyond 0.4, it becomes nearly constant (200–220 kJ mol–1). This observation suggests that the diffusion process in the low hydride concentration (x < 0.4) includes oxide as well as hydride diffusion, whereas, for 0.4 < x (<0.75), only hydride migrates, with second-nearest-neighbor (2NN) jumps as a rate-determining process, which is supported by DFT calculations. The Kissinger analysis of LaSrCoO3H0.70 yielded a similar Ea of 170–190 kJ mol–1, consistent with the 2NN hopping scenario. The presented method provides a facile tool for designing and improving hydride conductivity in oxyhydrides regardless of the presence of electronic conductivity.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.7b02240

DOI: 10.1021/acs.chemmater.7b02240

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.