Carbon-dioxide activation by methane with iron-doped barium zirconate in chemical looping cracking system

Shu Hikima, Martin Keller, Hiroki Matsuo, Yoshio Matsuzaki, Junichiro Otomo

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10 Citations (Scopus)


Highly efficient carriers are developed for hydrogen production by methane cracking with carbon-dioxide activation in a chemical looping system. The carrier materials comprise BaZr0.9Y0.1O3−δ (BZY) with a high proton conductivity and Fe as a base metal, and they are prepared by doping Fe into BZY. Thermal gravimetric analysis (TGA) showed that Fe-doped BZY (BaZr0.9−xFexY0.1O3−δ, BZFY) with x = 0.4 (BZFY40) exhibited a high activity for carbon deposition with methane thermal decomposition. Surface observation and kinetic analysis suggested that the high activity for carbon deposition results from the promotion of tubular carbon growth with growth-mode transition from horizontal to vertical direction for the tubular carbon on reduced BZFY40. The rapid growth of carbon tubes proceeded with the base-growth mechanism, which can provide an advantage in the stable cycle reactions. The carbon removal reaction with carbon dioxide was also investigated. In BZFY, the removal reaction was completed in ~10 min. BZFY reacted with carbon dioxide under carbon dioxide flow to generate barium carbonate. From the BZFY surface observation before and after the reactions, the BZFY plate that was mechanically broken during the carbon deposition and removal cycles could be repaired by filling cracks with carbonate in the BZFY that was generated via the reduction reaction with methane. Therefore, carbon removal from the BZFY surface with carbon dioxide contributes to maintaining the BZFY particle shape during cycles with the self-healing scheme. The BZFY40 carrier has a high activity and durability for the carbon deposition and removal cycle and provides an effective system design for carbon dioxide-free hydrogen generation.

Original languageEnglish
Article number128012
JournalChemical Engineering Journal
Publication statusPublished - Aug 1 2021

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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