A predictive model and mechanisms associated with hydrogen production via hydrothermal reactions of sulfide

Putri Setiani, Noriaki Watanabe, Atsushi Kishita, Noriyoshi Tsuchiya

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Hydrogen generation and the concurrent formation of sulfur products from hydrothermal reactions of aqueous sulfide solutions at pH values between 9 and 13 and temperatures between 280 and 330 C were studied. A hydrogen production model was developed by kinetic and statistical analysis of sulfide consumption rates and the ratio of hydrogen produced to sulfide consumed. Results showed that the amount of hydrogen generated in a given reaction may be predicted by a series of equations incorporating starting conditions such as the initial sulfide concentration, pH and temperature. The data from this study suggested that the overall hydrogen generation reaction mechanism consists of one or more elementary reactions which result in the formation of various sulfur products, such as polysulfides and sulfur oxyanions, depending on the reaction conditions. The possible specific sulfur compounds included pentasulfide (S 52-), thiosulfate (S2O3 2-), trithionate (S3O62-) and sulfate (SO42-). The production rate constants of these products increased with temperature, but were independent of pH. Additionally, it was indicated that increasing the reaction temperature and/or pH resulted in the formation of sulfur products with higher oxidation numbers. This work suggests that the optimal mechanism for hydrogen generation via the sulfur redox cycle, taking into account the requirement for sulfide regeneration, is that which forms trithionate as the sole sulfur product.

Original languageEnglish
Pages (from-to)11209-11221
Number of pages13
JournalInternational Journal of Hydrogen Energy
Issue number26
Publication statusPublished - 2013 Aug 30


  • Hydrogen production
  • Hydrothermal
  • Kinetic study
  • Predictive equation
  • Sulfur-water reaction

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology


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