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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}
}
  • ZnIn{sub 2}S{sub 4} as a photocatalyst for photosplitting water into H{sub 2} exhibits some fascinating advantages, such as low toxicity, good crystallinity, and considerable chemical stability. Currently, developing ZnIn{sub 2}S{sub 4}-based composite photocatalysts with different morphologies has received wide attention in order to improve the photocatalytic activity. In this contribution, a new ZnIn{sub 2}S{sub 4}/RGO/MoS{sub 2} photocatalytic system has been designed. The presence of the RGO is confirmed by x-ray photoelectron spectroscopy and FT-IR spectra. By optimization of solvothermal reaction temperatures, reaction time, and RGO introduction amount, up to 1.62 mmol/h ⋅ g of hydrogen evolution rate has been achieved.
  • Bulky AgGaS2 was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N2 flow for hydrogen production under visible light. To remove the impurity phase involved in the synthesized material and improve its crystallinity, the material was treated at various temperatures of 873-1123 K under H2S flow. Impurity phases were identified as {beta}-Ga2O3 and Ag9GaS6 with Rietveld analysis of XRD, and the local coordination structure around gallium atom in AgGaS2 was investigated by EXAFS. As the H2S-treatment temperature increased, the contribution from impurity phase was diminished. When the temperature reached 1123 K, the impurity phases weremore » completely removed and the material showed the highest photocatalytic activity.« less
  • In the MXenes family of two-dimensional transition-metal carbides there were successful demonstrations of co-catalysts with rutile TiO 2 for visible-light-induced solar hydrogen production from water splitting. The physicochemical properties of Ti 3C 2T x MXene coupled with TiO 2 were investigated by a variety of characterization techniques. The effect of the Ti 3C 2T x loading on the photocatalytic performance of the TiO 2/Ti 3C 2T x composites was elucidated. Moreover, with an optimized Ti 3C 2T x content of 5 wt %, the TiO 2/Ti 3C 2T x composite shows a 400 % enhancement in the photocatalytic hydrogen evolutionmore » reaction compared with that of pure rutile TiO 2. We also expanded our exploration to other MXenes (Nb 2CT x and Ti 2CT x) as co-catalysts coupled with TiO 2, and these materials also exhibited enhanced hydrogen production. These results manifest the generality of MXenes as effective co-catalysts for solar hydrogen production.« less
  • Highlights: • The ZnIn{sub 2}S{sub 4} (120, 140, 160, 180, and 200 °C) was prepared. • The activities splitting water to hydrogen under visible light were evaluated. • The activity achieved the best when hydrothermal temperature was 160 °C. • The activity order is related to the surface morphology and surface defects. - Abstract: A series of ZnIn{sub 2}S{sub 4} photocatalysts were successfully synthesized using the hydrothermal method with different hydrothermal temperatures (120, 140, 160, 180, and 200 °C) and characterized by various analysis techniques, such as UV–vis, XRD, SEM, BET and PL. The results indicated that these photocatalysts hadmore » a similar band gap. The hydrothermal temperature had a huge influence on the properties of the photocatalysts such as the BET surface area, the total pore volume, the average pore diameter, the defects and the morphology. The photocatalytic activities of ZnIn{sub 2}S{sub 4} were evaluated based on photocatalytic hydrogen production from water under visible-light irradiation. The activity order is attributed to the coefficient of the surface morphology and the surface defects. The hydrogen production efficiency achieved the best when the hydrothermal temperature was 160 °C. On the basis of the characterization of the catalysts, the effects of the hydrothermal temperature on the photocatalytic activity of ZnIn{sub 2}S{sub 4} were discussed.« less