The role of water for photodecomposition of aqueous hydrogen sulfide using stratified photocatalyst - Experimental part

Takeo Arai, Takatoshi Matsumoto, Shuhei Sakima, Kozo Shinoda, Umpei Nagashima, Kazuyuki Tohji

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Splitting of hydrogen sulfide using sunlight is a useful reaction to produce hydrogen. Alkaline sulfide solution, which is prepared by dissolving hydrogen sulfide into alkaline water, is selected as the reaction medium of photocatalytic hydrogen generation reaction. In this system, the photocatalytic reaction is assumed to occur as follows: 2H2O+2e -→H2+2OH- (1) 2S2-+2h +→S22- (2) However, as the reaction progresses white solids precipitate in the reaction medium. Furthermore, the HPLC analysis suggested that the ratio between the consumption of sulfide ion and the amount of hydrogen generation was about 3:2, which is not stoichiometric. Thus, in this paper, we characterized the white solid precipitate and tried to optimize the solution condition to prevent the precipitation of the same. From our study, the white solid precipitate was confirmed as sulfur derived from the oxidation of the disulfide ion. It was confirmed that the addition of sulfite ions prevented the oxidation of disulfide ions, which causes the precipitation. In the absence of sulfite ions and for sufide ion concentration less than 0.1M, the precipitation of sulfur occurs in a very short reaction time. On the other hand the hydrogen evolution rate retarded when the sulfide ion concentration is higher than 0.1M. This was due to the degradation of the stratified CdS particles. Thus, the optimal concentration of Na2S solution was determined to be around 0.1M.

Original languageEnglish
Title of host publicationWATER DYNAMICS
Subtitle of host publication3rd International Workshop on Water Dynamics
Number of pages4
Publication statusPublished - 2006 May 15
EventWATER DYANMICS: 3rd International Workshop on Water Dynamics - Sendai, Japan
Duration: 2005 Nov 162005 Nov 17

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


OtherWATER DYANMICS: 3rd International Workshop on Water Dynamics


  • Hydrogen generation
  • Hydrogen sulfide
  • Photocatalyst
  • Stratified material

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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