Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol

Photocatalytic reduction of carbon dioxide (CO2) with water (H2O) into solar fuels is considered as a promising strategy to simultaneously address the global energy and environmental issues. The main objective of this study was to design and fabricate photoreactor system and to synthesize Z-scheme a...

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Main Author:	Mohammed Bafaqeer, Abdullah Salem
Format:	Thesis
Language:	English
Published:	2019
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/85735/1/AbdullahSalemMohammedPSChE2019.pdf
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spelling	my-utm-ep.857352020-07-30T07:30:29Z Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol 2019 Mohammed Bafaqeer, Abdullah Salem TP Chemical technology Photocatalytic reduction of carbon dioxide (CO2) with water (H2O) into solar fuels is considered as a promising strategy to simultaneously address the global energy and environmental issues. The main objective of this study was to design and fabricate photoreactor system and to synthesize Z-scheme assembly of reduced graphene oxide (RGO) and protonated carbon nitride (pCN) based zinc vanadium oxide (ZnV2O6) nanocomposite for selective photoreduction of CO2 to solar fuels. The pure ZnV2O6, ZnV2O6/RGO, ZnV2O6/pCN and ZnV2O6/RGO/pCN nanocomposites were synthesized by a single step solvothermal method. The performance of nanocomposite catalysts was investigated in a liquid and gas phase photocatalytic systems under UV and visible light irradiations. The most effective catalyst in liquid phase system was ZnV2O6/RGO/pCN which gave a maximum methanol yield of 3726.7 µmol g-cat-1 using photoreactor without reflector and 5207.2 µmol g-cat-1 using photoreactor with reflector. Performance comparison revealed 1.4 times higher yield rate in photoreactor with reflector compared to photoreactor without reflector. Besides, weight percent ratio, effect of time and stability contributed significantly to enhance reactor performances. Using gas phase system, ZnV2O6/RGO/pCN nanocomposite demonstrated excellent photoactivity in the reduction of CO2 into carbon monoxide (CO), hydrogen (H2), methane (CH4) and methanol (CH3OH) under visible light irradiation. The CO evolution rate as a main product over ZnV2O6/RGO/pCN nanocomposite of 3756 µmol g-cat-1 was obtained. The quantum efficiency of 14.2 % was achieved for CH3OH production in a photoreactor with reflector, followed by 10.4 % and 0.25 % in photoreactor without reflector and fixed-bed photoreactor, respectively under visible light irradiation. Finally, Langmuir-Hinshelwood kinetic model was developed to investigate adsorption behaviors and photocatalytic oxidation and reduction process. In conclusion, solar photoreactor with reflector and modified ZnV2O6 nanocatalysts could make markedly higher CO2 reduction to fuels. 2019 Thesis http://eprints.utm.my/id/eprint/85735/ http://eprints.utm.my/id/eprint/85735/1/AbdullahSalemMohammedPSChE2019.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:131650 phd doctoral Universiti Teknologi Malaysia, Faculty of Engineering - School of Chemical & Energy Engineering Faculty of Engineering - School of Chemical & Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Mohammed Bafaqeer, Abdullah Salem Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
description	Photocatalytic reduction of carbon dioxide (CO2) with water (H2O) into solar fuels is considered as a promising strategy to simultaneously address the global energy and environmental issues. The main objective of this study was to design and fabricate photoreactor system and to synthesize Z-scheme assembly of reduced graphene oxide (RGO) and protonated carbon nitride (pCN) based zinc vanadium oxide (ZnV2O6) nanocomposite for selective photoreduction of CO2 to solar fuels. The pure ZnV2O6, ZnV2O6/RGO, ZnV2O6/pCN and ZnV2O6/RGO/pCN nanocomposites were synthesized by a single step solvothermal method. The performance of nanocomposite catalysts was investigated in a liquid and gas phase photocatalytic systems under UV and visible light irradiations. The most effective catalyst in liquid phase system was ZnV2O6/RGO/pCN which gave a maximum methanol yield of 3726.7 µmol g-cat-1 using photoreactor without reflector and 5207.2 µmol g-cat-1 using photoreactor with reflector. Performance comparison revealed 1.4 times higher yield rate in photoreactor with reflector compared to photoreactor without reflector. Besides, weight percent ratio, effect of time and stability contributed significantly to enhance reactor performances. Using gas phase system, ZnV2O6/RGO/pCN nanocomposite demonstrated excellent photoactivity in the reduction of CO2 into carbon monoxide (CO), hydrogen (H2), methane (CH4) and methanol (CH3OH) under visible light irradiation. The CO evolution rate as a main product over ZnV2O6/RGO/pCN nanocomposite of 3756 µmol g-cat-1 was obtained. The quantum efficiency of 14.2 % was achieved for CH3OH production in a photoreactor with reflector, followed by 10.4 % and 0.25 % in photoreactor without reflector and fixed-bed photoreactor, respectively under visible light irradiation. Finally, Langmuir-Hinshelwood kinetic model was developed to investigate adsorption behaviors and photocatalytic oxidation and reduction process. In conclusion, solar photoreactor with reflector and modified ZnV2O6 nanocatalysts could make markedly higher CO2 reduction to fuels.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mohammed Bafaqeer, Abdullah Salem
author_facet	Mohammed Bafaqeer, Abdullah Salem
author_sort	Mohammed Bafaqeer, Abdullah Salem
title	Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
title_short	Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
title_full	Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
title_fullStr	Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
title_full_unstemmed	Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
title_sort	zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol
granting_institution	Universiti Teknologi Malaysia, Faculty of Engineering - School of Chemical & Energy Engineering
granting_department	Faculty of Engineering - School of Chemical & Energy Engineering
publishDate	2019
url	http://eprints.utm.my/id/eprint/85735/1/AbdullahSalemMohammedPSChE2019.pdf
_version_	1747818444964757504

Zinc vanadium oxide coupled carbon nitride nanocomposite for photocatalytic carbon dioxide reduction to methanol

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