TY - GEN
T1 - The role of water for photodecomposition of aqueous hydrogen sulfide using stratified photocatalyst - Experimental part
AU - Arai, Takeo
AU - Matsumoto, Takatoshi
AU - Sakima, Shuhei
AU - Shinoda, Kozo
AU - Nagashima, Umpei
AU - Tohji, Kazuyuki
PY - 2006/5/15
Y1 - 2006/5/15
N2 - 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.
AB - 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.
KW - Hydrogen generation
KW - Hydrogen sulfide
KW - Photocatalyst
KW - Stratified material
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U2 - 10.1063/1.2207085
DO - 10.1063/1.2207085
M3 - Conference contribution
AN - SCOPUS:33845591745
SN - 0735403279
SN - 9780735403277
T3 - AIP Conference Proceedings
SP - 104
EP - 107
BT - WATER DYNAMICS
T2 - WATER DYANMICS: 3rd International Workshop on Water Dynamics
Y2 - 16 November 2005 through 17 November 2005
ER -