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Title: The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part

Abstract

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: 2H{sub 2}O + 2e{sup -} {yields} H{sub 2} + 2OH{sup -} (1) 2S{sup 2-} + 2h{sup +} {yields} S{sub 2}{sup 2-} (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 othermore » 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.« less

Authors:
; ;  [1];  [2];  [3];  [4]
  1. Graduate School of Environmental Studies, Tohoku University, Aramaki Aza Aoba 20, Aoba-Ku, Sendai 980-8579 (Japan)
  2. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba, Sendai 980-8577 (Japan)
  3. Deptertment of Geoscience and Technology, Tohoku University, Aramaki Aza Aoba 01, Aoba-Ku, Sendai 980-8579 (Japan)
  4. Grid Technology Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)
Publication Date:
OSTI Identifier:
20798639
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 833; Journal Issue: 1; Conference: 3. international workshop on water dynamics, Sendai (Japan), 16-17 Nov 2005; Other Information: DOI: 10.1063/1.2207085; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CADMIUM SULFIDES; CATALYSTS; DISULFIDES; HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; HYDROGEN; HYDROGEN SULFIDES; MOLECULAR IONS; OXIDATION; PHOTOCHEMISTRY; PRECIPITATION; SOLUTIONS; STOICHIOMETRY; SULFITES; SULFUR; WATER

Citation Formats

Arai, Takeo, Shinoda, Kozo, Tohji, Kazuyuki, Matsumoto, Takatoshi, Sakima, Shuhei, and Nagashima, Umpei. The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part. United States: N. p., 2006. Web. doi:10.1063/1.2207085.
Arai, Takeo, Shinoda, Kozo, Tohji, Kazuyuki, Matsumoto, Takatoshi, Sakima, Shuhei, & Nagashima, Umpei. The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part. United States. doi:10.1063/1.2207085.
Arai, Takeo, Shinoda, Kozo, Tohji, Kazuyuki, Matsumoto, Takatoshi, Sakima, Shuhei, and Nagashima, Umpei. Mon . "The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part". United States. doi:10.1063/1.2207085.
@article{osti_20798639,
title = {The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part},
author = {Arai, Takeo and Shinoda, Kozo and Tohji, Kazuyuki and Matsumoto, Takatoshi and Sakima, Shuhei and Nagashima, Umpei},
abstractNote = {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: 2H{sub 2}O + 2e{sup -} {yields} H{sub 2} + 2OH{sup -} (1) 2S{sup 2-} + 2h{sup +} {yields} S{sub 2}{sup 2-} (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.},
doi = {10.1063/1.2207085},
journal = {AIP Conference Proceedings},
number = 1,
volume = 833,
place = {United States},
year = {Mon May 15 00:00:00 EDT 2006},
month = {Mon May 15 00:00:00 EDT 2006}
}