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Title: AgGaS{sub 2}-type photocatalysts for hydrogen production under visible light: Effects of post-synthetic H{sub 2}S treatment

Abstract

Bulky AgGaS{sub 2} was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N{sub 2} flow for hydrogen production under visible light. To remove impurity phases involved in the synthesized material and improve crystallinity, the material was treated at various temperatures of 873-1123 K under H{sub 2}S flow. Impurity phases were identified as {beta}-Ga{sub 2}O{sub 3} and Ag{sub 9}GaS{sub 6} with the cell refinements of XRD and the local coordination structure around gallium atom in AgGaS{sub 2} was investigated by EXAFS. As the H{sub 2}S-treatment temperature increased, the contribution from impurity phases was diminished. When the temperature reached 1123 K, the impurity phases were completely removed and the material showed the highest photocatalytic activity. Thus, the post-synthetic H{sub 2}S treatment could be applied for the synthesis of sulfide-type photocatalysts with high activity. - Graphical abstract: Post-treatment of AgGaS{sub 2} under H{sub 2}S flow at 1123 K resulted in the well-defined chalcopyrite structure, which was revealed mainly by Rietveld analysis of XRD and detailed EXAFS study. The diameters of AgGaS{sub 2} particles treated at 873-1123 K under H{sub 2}S gas flow are ca. 2-3 nm, almost the same as that of H{sub 2}S-untreated material. In untreated sample,more » AgGaS{sub 2} particles were surrounded by the broken powders having sharp edges. But there were almost no broken particles and the surface became smoother for AgGaS{sub 2} treated with H{sub 2}S gas at 1123 K. The rates of hydrogen evolution over H{sub 2}S treated AgGaS{sub 2} at higher temperatures (1073 and 1123 K) were higher than those of photocatalysts untreated or treated at lower temperatures (873, 973 K). There is almost no correlation between BET surface areas and hydrogen evolution rates.« less

Authors:
 [1];  [2];  [2];  [2];  [3]
  1. Eco-friendly Catalysis and Energy Laboratory (NRL), Department of Chemical Engineering, School of Environmental Science and Engineering (Korea, Republic of)
  2. Beamline Research Division, Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang 790-784 (Korea, Republic of)
  3. Eco-friendly Catalysis and Energy Laboratory (NRL), Department of Chemical Engineering, School of Environmental Science and Engineering (Korea, Republic of), E-mail: jlee@postech.ac.kr
Publication Date:
OSTI Identifier:
21015753
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 3; Other Information: DOI: 10.1016/j.jssc.2007.01.008; PII: S0022-4596(07)00025-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; CATALYSTS; FINE STRUCTURE; GALLIUM OXIDES; GALLIUM SULFIDES; GAS FLOW; HYDROGEN PRODUCTION; HYDROGEN SULFIDES; IMPURITIES; PARTICLES; PHOTOCATALYSIS; SEMICONDUCTOR MATERIALS; SILVER SULFIDES; SYNTHESIS; TEMPERATURE RANGE 1000-4000 K; VISIBLE RADIATION; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY

Citation Formats

Jang, Jum Suk, Choi, Sun Hee, Shin, Namsoo, Yu, Chungjong, and Lee, Jae Sung. AgGaS{sub 2}-type photocatalysts for hydrogen production under visible light: Effects of post-synthetic H{sub 2}S treatment. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.01.008.
Jang, Jum Suk, Choi, Sun Hee, Shin, Namsoo, Yu, Chungjong, & Lee, Jae Sung. AgGaS{sub 2}-type photocatalysts for hydrogen production under visible light: Effects of post-synthetic H{sub 2}S treatment. United States. doi:10.1016/j.jssc.2007.01.008.
Jang, Jum Suk, Choi, Sun Hee, Shin, Namsoo, Yu, Chungjong, and Lee, Jae Sung. Thu . "AgGaS{sub 2}-type photocatalysts for hydrogen production under visible light: Effects of post-synthetic H{sub 2}S treatment". United States. doi:10.1016/j.jssc.2007.01.008.
@article{osti_21015753,
title = {AgGaS{sub 2}-type photocatalysts for hydrogen production under visible light: Effects of post-synthetic H{sub 2}S treatment},
author = {Jang, Jum Suk and Choi, Sun Hee and Shin, Namsoo and Yu, Chungjong and Lee, Jae Sung},
abstractNote = {Bulky AgGaS{sub 2} was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N{sub 2} flow for hydrogen production under visible light. To remove impurity phases involved in the synthesized material and improve crystallinity, the material was treated at various temperatures of 873-1123 K under H{sub 2}S flow. Impurity phases were identified as {beta}-Ga{sub 2}O{sub 3} and Ag{sub 9}GaS{sub 6} with the cell refinements of XRD and the local coordination structure around gallium atom in AgGaS{sub 2} was investigated by EXAFS. As the H{sub 2}S-treatment temperature increased, the contribution from impurity phases was diminished. When the temperature reached 1123 K, the impurity phases were completely removed and the material showed the highest photocatalytic activity. Thus, the post-synthetic H{sub 2}S treatment could be applied for the synthesis of sulfide-type photocatalysts with high activity. - Graphical abstract: Post-treatment of AgGaS{sub 2} under H{sub 2}S flow at 1123 K resulted in the well-defined chalcopyrite structure, which was revealed mainly by Rietveld analysis of XRD and detailed EXAFS study. The diameters of AgGaS{sub 2} particles treated at 873-1123 K under H{sub 2}S gas flow are ca. 2-3 nm, almost the same as that of H{sub 2}S-untreated material. In untreated sample, AgGaS{sub 2} particles were surrounded by the broken powders having sharp edges. But there were almost no broken particles and the surface became smoother for AgGaS{sub 2} treated with H{sub 2}S gas at 1123 K. The rates of hydrogen evolution over H{sub 2}S treated AgGaS{sub 2} at higher temperatures (1073 and 1123 K) were higher than those of photocatalysts untreated or treated at lower temperatures (873, 973 K). There is almost no correlation between BET surface areas and hydrogen evolution rates.},
doi = {10.1016/j.jssc.2007.01.008},
journal = {Journal of Solid State Chemistry},
number = 3,
volume = 180,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}