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Title:	Bio-inspired C-doped g-C3N4-based core-shell heterojunction photocatalyst for hydrogen generation
Authors:	Mohamad Azuwa Mohamed (P89056)
Supervisor:	Muhammad Fauzi Mohd Zain, Prof Dato' Dr.
Keywords:	Fossil fuels Solar energy Power resources Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	10-Oct-2019
Description:	The use of fossil fuels to meet the global energy demand is coupled with ever worsening global warming and fossils resources depletion leading to the urgent development of a clean, sustainable, and renewable alternative. Solar fuel production based on photocatalytic hydrogen evolution is one of the promising strategies to address this crisis. Recently, graphitic carbon nitride (g-C3N4) has emerged as an innovative photocatalyst for solar fuel production as well as organic contaminants decomposition. However, pure g-C3N4 suffers from the insufficient sunlight absorption, low surface area, and the fast recombination of electron-hole pairs, resulting in low photocatalytic activity. Therefore, the primary aim of this study is to develop bio-template C-doped g-C3N4 (CCN) based core-shell heterojunction photocatalyst that exhibits the optimal conduction and valence band edge alignment, excellent light absorption and charges separation behavior. In this study, CCN based core-shell heterojunction photocatalyst with in-situ carbon doping have been successfully prepared by bio-template hydrothermal techniques. The kapok fiber has been used as bio-template to control the crystal growth and in-situ carbon doping sources. The effect of different calcination temperature (300 - 600 °C) and type of metal oxides precursor concentration (0.5 - 2.0 M) on the formation CCN-based coreshell heterojunctions have been systematically investigated. The in-depth understanding on crystalline phase, structural morphology, band gap, elemental analysis and charge carrier behavior of the prepared samples were carried out by various characterization techniques such as XRD, FESEM, TEM/HRTEM, N2 adsorption-desorption, UV-Vis-NIR and PL spectroscopy, TGA-DTG, FTIR, XPS, and photoelectrochemical (PEC) measurement. It was found that the calcination temperature of 500 °C and metal oxides precursor concentration of 1.5 M was the best synthesis parameter for the formation of core-shell heterojunction which consists of CCN as shell and metal oxides as the core. Moreover, the simultaneous growth of CCN and metal oxides (TiO2 and ZnO) has also induced the in-situ C, N co-doping in the metal oxides lattice structures as confirmed by XPS and UV-Vis-NIR analysis. The charge separation behavior and light absorption capability of heterojunction photocatalyst with core-shell structures have significantly improved in comparison with typical heterostructures. The superior charge separation behavior had led to excellent photocatalytic activity in hydrogen production reaction as well as organic pollutants degradation. The highest hydrogen production rate of ~626.0 μmol h-1 g -1 under simulated solar irradiation was recorded over bio-template CCN@TiO2 coreshell heterojunction photocatalyst which was approximately 1.5, 3.0, 8.0, and 17.0 folds of CCN@ZnO, CCN, g-C3N4, and TiO2 samples, respectively. Obviously, the well-developed interconnected heterojunction formation with appropriate CCN and metal oxides contents in core-shell nanoarchitectures system is a prime factor for the future design of a highly efficient visible light active photocatalyst.,Ph.D.
Pages:	298
Call Number:	TP318.M833 2019 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Fuel Cell Institute / Institut Sel Fuel

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