Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting

Photocatalytic hydrogen (H2 ) generation is one o f the most promising solutions to convert solar power into clean energy to replace non-renewable fossil fuel. The objective of this study is to investigate montmorillonite (MMT) dispersed and silver (Ag)-bridged protonated carbon nitride/titanium dio...

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Main Author:	Mohamad Lazif, Nur Fajrina
Format:	Thesis
Language:	English
Published:	2019
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/86209/1/NurFajrinaMohamadMSChE2019.pdf
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spelling	my-utm-ep.862092020-08-30T09:07:52Z Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting 2019 Mohamad Lazif, Nur Fajrina TP Chemical technology Photocatalytic hydrogen (H2 ) generation is one o f the most promising solutions to convert solar power into clean energy to replace non-renewable fossil fuel. The objective of this study is to investigate montmorillonite (MMT) dispersed and silver (Ag)-bridged protonated carbon nitride/titanium dioxide (pCN/TiO2) Zscheme heterojunction composite for stimulating photocatalytic H2 evolution under UV and visible light in different photocatalytic reactor systems. The newly designed MMT-Ag/pCN-TiO2 composite photocatalysts were fabricated through a sol-gel assisted hydrothermal method and were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray mapping, transmission electron microscopy, Brunauer-Emmett-Teller, ultraviolet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy. The photocatalytic activity was tested using slurry, fixed bed and monolith photo-reactor systems for continuous H2 production. Using slurry system, MMT-Ag/pCN-TiO2 photo-catalyst produced 667 \|imol h-1 of H2 which is 8.41 and 9.66 times higher than pCN/TiO2 and TiO2 samples, respectively. The efficiency was improved due to formation of heterojunction with faster charges separation, whereas, Ag provides hot photo-generated electrons by surface plasmon resonance and MMT traps electrons for H2 production. Optimization reveals that the highest production of H2 was obtained at pH 7, glycerol concentration of 5 wt. % and 0.15 g of catalyst loading using slurry reactor. Furthermore, by applying an engineering approach MMT-Ag/pCN-TiO2 showed H2 production rate was increased to 8230 prnol h- 1 using a monolith reactor, which are 9.01 and 12.34 times higher than fixed-bed and slurry photo-reactors. The monolith honeycomb reactor exhibited a higher apparent quantum yield and space yield of 39.85 % and 54.86 \|imol h-1cm"3 compared to slurry (22.36 %, 5.13 \|imol h-1cm"3) and fixed-bed reactors (4.42 %, 6.09 \|imol h-1cm"3). The superior performance of a monolith reactor was due to higher photon flux utilization, large illuminated surface area and processing volume. The schematic of type II heterojunction and Z-scheme mechanism of MMTAg/ pCN-TiO2 were developed and the photocatalytic performance was compared in all types o f systems. In conclusion, excellent performance o f composite catalyst using a monolith reactor compared to a slurry and fixed-bed reactor for H2 production would offer a new opportunity in engineering approach for renewable fuels applications. 2019 Thesis http://eprints.utm.my/id/eprint/86209/ http://eprints.utm.my/id/eprint/86209/1/NurFajrinaMohamadMSChE2019.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:131571 masters 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 Mohamad Lazif, Nur Fajrina Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
description	Photocatalytic hydrogen (H2 ) generation is one o f the most promising solutions to convert solar power into clean energy to replace non-renewable fossil fuel. The objective of this study is to investigate montmorillonite (MMT) dispersed and silver (Ag)-bridged protonated carbon nitride/titanium dioxide (pCN/TiO2) Zscheme heterojunction composite for stimulating photocatalytic H2 evolution under UV and visible light in different photocatalytic reactor systems. The newly designed MMT-Ag/pCN-TiO2 composite photocatalysts were fabricated through a sol-gel assisted hydrothermal method and were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray mapping, transmission electron microscopy, Brunauer-Emmett-Teller, ultraviolet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy. The photocatalytic activity was tested using slurry, fixed bed and monolith photo-reactor systems for continuous H2 production. Using slurry system, MMT-Ag/pCN-TiO2 photo-catalyst produced 667 \|imol h-1 of H2 which is 8.41 and 9.66 times higher than pCN/TiO2 and TiO2 samples, respectively. The efficiency was improved due to formation of heterojunction with faster charges separation, whereas, Ag provides hot photo-generated electrons by surface plasmon resonance and MMT traps electrons for H2 production. Optimization reveals that the highest production of H2 was obtained at pH 7, glycerol concentration of 5 wt. % and 0.15 g of catalyst loading using slurry reactor. Furthermore, by applying an engineering approach MMT-Ag/pCN-TiO2 showed H2 production rate was increased to 8230 prnol h- 1 using a monolith reactor, which are 9.01 and 12.34 times higher than fixed-bed and slurry photo-reactors. The monolith honeycomb reactor exhibited a higher apparent quantum yield and space yield of 39.85 % and 54.86 \|imol h-1cm"3 compared to slurry (22.36 %, 5.13 \|imol h-1cm"3) and fixed-bed reactors (4.42 %, 6.09 \|imol h-1cm"3). The superior performance of a monolith reactor was due to higher photon flux utilization, large illuminated surface area and processing volume. The schematic of type II heterojunction and Z-scheme mechanism of MMTAg/ pCN-TiO2 were developed and the photocatalytic performance was compared in all types o f systems. In conclusion, excellent performance o f composite catalyst using a monolith reactor compared to a slurry and fixed-bed reactor for H2 production would offer a new opportunity in engineering approach for renewable fuels applications.
format	Thesis
qualification_level	Master's degree
author	Mohamad Lazif, Nur Fajrina
author_facet	Mohamad Lazif, Nur Fajrina
author_sort	Mohamad Lazif, Nur Fajrina
title	Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
title_short	Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
title_full	Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
title_fullStr	Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
title_full_unstemmed	Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
title_sort	silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting
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/86209/1/NurFajrinaMohamadMSChE2019.pdf
_version_	1747818505095348224

Silver-montmorillonite modified titanium dioxide assisted carbon nitride nanocomposites for photocatalytic hydrogen production through water splitting

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