In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin

Kaolin-based graphitic carbon nitride (g-CNx) composite photocatalysts were synthesized from a urea precursor using a commercial kaolin. Structural characterization by X-ray diffraction and infrared spectroscopy (FTIR) verified the successful thermal polycondensation of g-CNx along the thermal dehyd...

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Main Authors: Balázs Zsirka, Orsolya Fónagy, Veronika Vágvölgyi, Tatjána Juzsakova, Lajos Fodor, Csilla Őze
Format: Article
Language:English
Published: MDPI AG 2024-09-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/14/9/793
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author Balázs Zsirka
Orsolya Fónagy
Veronika Vágvölgyi
Tatjána Juzsakova
Lajos Fodor
Csilla Őze
author_facet Balázs Zsirka
Orsolya Fónagy
Veronika Vágvölgyi
Tatjána Juzsakova
Lajos Fodor
Csilla Őze
author_sort Balázs Zsirka
collection DOAJ
description Kaolin-based graphitic carbon nitride (g-CNx) composite photocatalysts were synthesized from a urea precursor using a commercial kaolin. Structural characterization by X-ray diffraction and infrared spectroscopy (FTIR) verified the successful thermal polycondensation of g-CNx along the thermal dehydroxylation of kaolinite to metakaolin at 550 °C. The g-CNx content of the composites were estimated by thermogravimetry and CHN analysis, ranging from ca. 87 m/m% to ca. 2 m/m% of dry mass. The addition of kaolin during the composite synthesis was found to have a significant effect: the yield of in situ formed g-CNx drastically decreased (from ca. 4.9 m/m% to 3.8–0.1 m/m%) with increasing kaolin content. CHN and FTIR indicated the presence of nitrogen-rich g-CNx, having a specific surface area of 50 m<sup>2</sup>/g, which synergistically increased after composite synthesis to 67–82 m<sup>2</sup>/g. Estimated optical band gaps indicated the affinity to absorb in the visible light spectrum (λ < 413 nm). Photocatalytic activity upon both UV and artificial sunlight irradiation was observed by hydroxyl radical evolution, however, without the synergistic effect expected from the favorable porosity.
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spelling doaj-art-fb35cc6cb1a14f508d69720c6a6d77872025-08-20T01:55:28ZengMDPI AGCrystals2073-43522024-09-0114979310.3390/cryst14090793In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial KaolinBalázs Zsirka0Orsolya Fónagy1Veronika Vágvölgyi2Tatjána Juzsakova3Lajos Fodor4Csilla Őze5Research Group of Analytical Chemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Environmental and Inorganic Photochemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Analytical Chemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungarySustainability Solutions Research Laboratory, Research Centre for Biochemical, Environmental and Chemical Engineering, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Environmental and Inorganic Photochemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryDepartment of Materials Engineering, Research Centre for Engineering Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryKaolin-based graphitic carbon nitride (g-CNx) composite photocatalysts were synthesized from a urea precursor using a commercial kaolin. Structural characterization by X-ray diffraction and infrared spectroscopy (FTIR) verified the successful thermal polycondensation of g-CNx along the thermal dehydroxylation of kaolinite to metakaolin at 550 °C. The g-CNx content of the composites were estimated by thermogravimetry and CHN analysis, ranging from ca. 87 m/m% to ca. 2 m/m% of dry mass. The addition of kaolin during the composite synthesis was found to have a significant effect: the yield of in situ formed g-CNx drastically decreased (from ca. 4.9 m/m% to 3.8–0.1 m/m%) with increasing kaolin content. CHN and FTIR indicated the presence of nitrogen-rich g-CNx, having a specific surface area of 50 m<sup>2</sup>/g, which synergistically increased after composite synthesis to 67–82 m<sup>2</sup>/g. Estimated optical band gaps indicated the affinity to absorb in the visible light spectrum (λ < 413 nm). Photocatalytic activity upon both UV and artificial sunlight irradiation was observed by hydroxyl radical evolution, however, without the synergistic effect expected from the favorable porosity.https://www.mdpi.com/2073-4352/14/9/793graphitic carbon nitridephotocatalystcompositekaolinmetakaolinstructural characterization
spellingShingle Balázs Zsirka
Orsolya Fónagy
Veronika Vágvölgyi
Tatjána Juzsakova
Lajos Fodor
Csilla Őze
In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
Crystals
graphitic carbon nitride
photocatalyst
composite
kaolin
metakaolin
structural characterization
title In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
title_full In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
title_fullStr In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
title_full_unstemmed In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
title_short In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin
title_sort in situ synthesis and characterization of graphitic carbon nitride metakaolin composite photocatalysts using a commercial kaolin
topic graphitic carbon nitride
photocatalyst
composite
kaolin
metakaolin
structural characterization
url https://www.mdpi.com/2073-4352/14/9/793
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