Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)

Carbon dot (CD)-modified graphitic carbon nitride (g-C3N4) photocatalysts were synthesized through a one-step homogeneous thermal pyrolysis. The synergetic effect of citric acid (Cit) and g-C3N4/CDs for high-performance visible light Cr(VI) photocatalytic reduction had been investigated. Cit was not...

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Autores principales:	Jiamin Liu, Jianjun Li, Juan Liang, Chengjun Jing, Jiaxiu Guo
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	cds chromium (vi) citric acid g-c3n4 hydrogen peroxide (h2o2) Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350
Acceso en línea:	https://doaj.org/article/73f4be82a5c34d11b8ef4b5be7579a9f
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spelling	oai:doaj.org-article:73f4be82a5c34d11b8ef4b5be7579a9f2021-11-05T17:08:41ZSynergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)2709-80282709-803610.2166/aqua.2021.163https://doaj.org/article/73f4be82a5c34d11b8ef4b5be7579a9f2021-06-01T00:00:00Zhttp://aqua.iwaponline.com/content/70/4/570https://doaj.org/toc/2709-8028https://doaj.org/toc/2709-8036Carbon dot (CD)-modified graphitic carbon nitride (g-C3N4) photocatalysts were synthesized through a one-step homogeneous thermal pyrolysis. The synergetic effect of citric acid (Cit) and g-C3N4/CDs for high-performance visible light Cr(VI) photocatalytic reduction had been investigated. Cit was not only acted as a hole scavenger, but might also form surface charge transfer complexes (CTC) with g-C3N4 which delivered electrons on the Highest Occupied Molecular Orbital (HOMO) of Cit to the conduction band (CB) of g-C3N4. CDs decorated on g-C3N4 could provide channels for the preferential transfer of electrons on CTC to the CB of g-C3N4 as well as improved separation of the charge carriers. Owing to these synergistic effects, g-C3N4/CDs displayed much higher photocatalytic performance for the reduction of Cr(VI), which was 1.89 times higher than g-C3N4. Moreover, the synergetic photocatalytic reduction mechanisms of aqueous Cr(VI) were proposed to elucidate the active species formation and photogenerated electron transfer. The results suggested that the in situ generated hydrogen peroxide (H2O2) dominated the reduction of Cr(VI). The addition of Cit could trigger the in situ generation of H2O2 and the decorated CDs further enhanced the reaction. This work demonstrated the role of widely existed Cit on the photocatalytic reduction of Cr(VI) in natural aquatic environment. HIGHLIGHTS g-C3N4/CD photocatalysts were synthesized for Cr(VI) reduction.; CDs promoted light harvest and improved the separation of charge carriers.; Cit triggered the visible light photocatalytic reduction of Cr(VI) over g-C3N4/CDs.; H2O2 is the main effective activator for Cr(VI) reduction in the g-C3N4/Cit system.; The photocatalytic reduction pathways of Cr(VI) in the presence of cit were proposed.;Jiamin LiuJianjun LiJuan LiangChengjun JingJiaxiu GuoIWA Publishingarticlecdschromium (vi)citric acidg-c3n4hydrogen peroxide (h2o2)Environmental technology. Sanitary engineeringTD1-1066Environmental sciencesGE1-350ENAqua, Vol 70, Iss 4, Pp 570-586 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cds chromium (vi) citric acid g-c3n4 hydrogen peroxide (h2o2) Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350
spellingShingle	cds chromium (vi) citric acid g-c3n4 hydrogen peroxide (h2o2) Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Jiamin Liu Jianjun Li Juan Liang Chengjun Jing Jiaxiu Guo Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
description	Carbon dot (CD)-modified graphitic carbon nitride (g-C3N4) photocatalysts were synthesized through a one-step homogeneous thermal pyrolysis. The synergetic effect of citric acid (Cit) and g-C3N4/CDs for high-performance visible light Cr(VI) photocatalytic reduction had been investigated. Cit was not only acted as a hole scavenger, but might also form surface charge transfer complexes (CTC) with g-C3N4 which delivered electrons on the Highest Occupied Molecular Orbital (HOMO) of Cit to the conduction band (CB) of g-C3N4. CDs decorated on g-C3N4 could provide channels for the preferential transfer of electrons on CTC to the CB of g-C3N4 as well as improved separation of the charge carriers. Owing to these synergistic effects, g-C3N4/CDs displayed much higher photocatalytic performance for the reduction of Cr(VI), which was 1.89 times higher than g-C3N4. Moreover, the synergetic photocatalytic reduction mechanisms of aqueous Cr(VI) were proposed to elucidate the active species formation and photogenerated electron transfer. The results suggested that the in situ generated hydrogen peroxide (H2O2) dominated the reduction of Cr(VI). The addition of Cit could trigger the in situ generation of H2O2 and the decorated CDs further enhanced the reaction. This work demonstrated the role of widely existed Cit on the photocatalytic reduction of Cr(VI) in natural aquatic environment. HIGHLIGHTS g-C3N4/CD photocatalysts were synthesized for Cr(VI) reduction.; CDs promoted light harvest and improved the separation of charge carriers.; Cit triggered the visible light photocatalytic reduction of Cr(VI) over g-C3N4/CDs.; H2O2 is the main effective activator for Cr(VI) reduction in the g-C3N4/Cit system.; The photocatalytic reduction pathways of Cr(VI) in the presence of cit were proposed.;
format	article
author	Jiamin Liu Jianjun Li Juan Liang Chengjun Jing Jiaxiu Guo
author_facet	Jiamin Liu Jianjun Li Juan Liang Chengjun Jing Jiaxiu Guo
author_sort	Jiamin Liu
title	Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
title_short	Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
title_full	Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
title_fullStr	Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
title_full_unstemmed	Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)
title_sort	synergistic effect of citric acid and carbon dots modified g-c3n4 for enhancing photocatalytic reduction of cr(vi)
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/73f4be82a5c34d11b8ef4b5be7579a9f
work_keys_str_mv	AT jiaminliu synergisticeffectofcitricacidandcarbondotsmodifiedgc3n4forenhancingphotocatalyticreductionofcrvi AT jianjunli synergisticeffectofcitricacidandcarbondotsmodifiedgc3n4forenhancingphotocatalyticreductionofcrvi AT juanliang synergisticeffectofcitricacidandcarbondotsmodifiedgc3n4forenhancingphotocatalyticreductionofcrvi AT chengjunjing synergisticeffectofcitricacidandcarbondotsmodifiedgc3n4forenhancingphotocatalyticreductionofcrvi AT jiaxiuguo synergisticeffectofcitricacidandcarbondotsmodifiedgc3n4forenhancingphotocatalyticreductionofcrvi
_version_	1718444106583113728

Synergistic effect of citric acid and carbon dots modified g-C3N4 for enhancing photocatalytic reduction of Cr(VI)

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