Outstanding Properties and Performance of CaTi0.5Mn0.5O3–δ for Solar-Driven Thermochemical Hydrogen Production

Xin Qian*, Jiangang He, Emanuela Mastronardo, Bianca Baldassarri, Weizi Yuan, Christopher Wolverton, Sossina M. Haile

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Variable valence oxides of the perovskite crystal structure have emerged as promising candidates for solar hydrogen production via two-step thermochemical cycling. Here, we report the exceptional efficacy of the perovskite CaTi0.5Mn0.5O3–δ (CTM55) for this process. The combination of intermediate enthalpy, ranging between 200 and 280 kJ (mol-O)−1, and large entropy, ranging between 120 and 180 J (mol-O)−1 K−1, of CTM55 create favorable conditions for water splitting. The oxidation state changes are dominated by Mn, with Ti stabilizing the cubic phase and increasing its reduction enthalpy. A hydrogen yield of 10.0 ± 0.2 mL g−1 is achieved in a cycle between 1,350°C (reduction) and 1,150°C (water splitting) and a total cycle time of 1.5 h, exceeding all previous fuel production reports. The gas evolution rate suggests rapid material kinetics, and, at 1,150°C and higher, a process primarily limited by the magnitude of the thermodynamic driving force.

Original languageEnglish (US)
Pages (from-to)688-708
Number of pages21
Issue number2
StatePublished - Feb 3 2021


  • MAP3: Understanding
  • inorganic perovskite
  • oxygen non-stoichiometry
  • phase transition
  • solar fuel
  • thermo-kinetic limit
  • thermochemical hydrogen production
  • thermodynamic properties

ASJC Scopus subject areas

  • Materials Science(all)


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