First-principles calculation on electronic properties of zinc oxide by zinc–air system

Mohamad, Ahmad Azmin; Hassan, Muhammad Syafiq; Yaakob, Muhamad Kamil; Taib, Mohamad Fariz Mohamad; Badrudin, F. W.; Hassan, Oskar Hasdinor; Yahya, Muhd Zu Azhan

doi:10.1016/j.jksues.2015.08.002

Cited by 22 publications

(14 citation statements)

References 21 publications

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“…Here, ZnO shows direct band gap because the maximum valence band and minimum conduction band are at the same point, in agreement with the literature, e.g. Honglin et al and Mohamad et al[26,27]. Gap between valence band and conduction band (Eg) is 0.76 eV.…”

supporting

confidence: 91%

The study of structural, morphological and optical properties of (Al, Ga)-doped ZnO: DFT and experimental approaches

Sikam

Moontragoon

Ikonić

et al. 2019

Applied Surface Science

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ZnO is widely studied for several applications such as a photocatalyst, a working electrode for dye-sensitized solar cells and for thermoelectric devices. This work studies the effect of an increase in the number of carriers by doping ZnO with Al and Ga. The 6.25 mol% of Al-doped ZnO, 6.25 mol% of Ga-doped ZnO, and 12.5 mol% of (Al, Ga) co-doped ZnO nanoparticles were prepared using combustion method. The prepared samples were then characterized by X-ray diffraction, transmission electron microscope, energy-dispersive X-ray spectroscopy and UV-visible spectroscopy techniques. Moreover, density functional theory (DFT) was also employed for computational studies of Al and Ga doped ZnO. Optimized structures, density of states (DOS) and band structures of these materials were calculated using Vienna Ab initio Simulation Package code. From this study, Al and Ga are found to play an important role in morphology and optical properties of the ZnO, changing the band gap and Fermi level of ZnO. Then, the prepared samples were characterised for their thermoelectric properties, and modelling of thermoelectric properties of ZnO, Al-doped ZnO, Ga-doped ZnO and (Al, Ga)-co doped ZnO was performed using BoltzTraP code. Furthermore, the Seebeck coefficient, electrical conductivity, relaxation time, electronic thermal conductivity and power factor were studied. The experimental and computational results are pointing in the same direction, that the thermoelectric properties of the ZnO are changed by doping: the semiconducting ZnO transforms into metallic ZnO when doped with Al and Ga. This leads to ZnO showing new thermoelectric properties, in particular the Ga-doped ZnO and (Al, Ga)-co doped ZnO: they provide high electrical conductivity and power factor. Therefore, it is expected that these good properties might promote the ZnO to be a potential candidate for applications, especially in high efficiency thermoelectric devices.

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supporting

confidence: 91%

The study of structural, morphological and optical properties of (Al, Ga)-doped ZnO: DFT and experimental approaches

Sikam

Moontragoon

Ikonić

et al. 2019

Applied Surface Science

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“…Besides, the selected area electron diffraction (SAED) and transmission electron microscopy (TEM) analysis confirmed the single crystalline nature with (0001) crystal facet along the c-axis. This is further supported by density functional theory (DFT) (Mohamad et al, 2017). As shown in (Fig.…”

Section: Zno As Photocatalystsupporting

confidence: 65%

“…The DOS determines the electron distribution function in an energy level, and to illuminate the chemical interaction in ZnO, all atoms were calculated by total (TDOS). The Fermi level for ZnO was stated at 0 eV, while DOS has been positioned between energy levels from − 25 to 25 (Samadi et al, 2016;Mohamad et al, 2017). under license number 4978591406457, copyright 2016 Elsevier.…”

Section: Zno As Photocatalystmentioning

confidence: 99%

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Boosting light-driven CO2 reduction into solar fuels: Mainstream avenues for engineering ZnO-based photocatalysts

Patial

Kumar

Raizada

et al. 2021

Environmental Research

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The realization of artificial photosynthesis in the photocatalytic CO 2 transformation into valuable chemicals or solar fuels, such as CO, CH 4 , HCOOH, and CH 3 OH, by solar-light harvesting is a promising solution to both global-warming and energy-supply issues. Recently, zinc oxide (ZnO) has emerged as an excellent oxidative photocatalyst among non-titanium metal oxides due to its availability, outstanding semiconducting and optical properties, non-toxicity, affordability, and ease of synthesis. However, ZnO wide bandgap and inability to absorb in the visible region has demanded particular modification for its practical use as a sustainable photocatalyst. This review provides a panorama of the latest advancement on ZnO photocatalysis for CO 2 reduction with an overview of fundamental aspects. Various modification strategies such as transition metal and non-metal doping, loading of plasmonic metals, and surface vacancy engineering for tunning the properties and improving the performance of ZnO are elaborated. Composites or hetero-structuralization-based Z-scheme formation is also presented along with a detailed photocatalytic reduction mechanism. Moreover, a new novel Step-scheme (Sscheme) heterostructure modification with a charge transfer pathway mechanism is also highlighted. Finally, the key challenges and new directions in this field are proposed to provide a new vision for further improvement for ZnO-based photocatalytic CO 2 conversion.

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“…By contrast, electrical properties are exhibited when the motion of the electron is asymmetric. The energy band gap was analyzed, which demonstrated that the energy band gap of hemimorphite was 3.336 eV, differing greatly from another zinc oxide ore [19], but it was close to that of smithsonite (3.529 eV) [20]. These properties indicate the weak electron mobility and poor conductivity of hemimorphite.…”

Section: Analysis Of Energy Band Structure and Density Of States Of Hmentioning

confidence: 99%

Basic Characteristics of Hemimorphite and Its Transformation Mechanism with Na2CO3

et al. 2018

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The crystal of hemimorphite is a non-conductor. The Si-O bond in the crystal is strong, whereas the Zn-O bond is weak. These properties lead to the easy breakage of the Zn-O bond in the crushing process of hemimorphite. Thus, the interaction between minerals and polar water molecules is strong, and natural floatability of ores is poor. This study systematically investigated the characteristics of hemimorphite and its action mechanism with Na 2 CO 3. Results of SEM-EDS showed that the surface of hemimorphite dissolved after interacting with Na 2 CO 3 , and the contents of Si and O decreased, whereas Zn and C increased. XPS analysis showed that the carbonate group was detected. The interaction between CO 3 2− and hemimorphite was calculated using the first principles calculation based on density functional theory. The results indicate that an O atom in CO 3 2− interacted with Zn 2+ from the (100) plane of hemimorphite. The interaction between Zn and O atoms was not strong, and the Zn atoms were not completely displaced, which was proven by density of state analysis and the EDS and XPS results. The Mulliken population showed that the O-Zn bond was the atomic bonding of CO 3 2− with Zn 2+ and exhibited properties of ionic bonds. Thus, hemimorphite transformed to smithsonite-like mineral (ZnCO 3) when acting with CO 3 2− .

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First-principles calculation on electronic properties of zinc oxide by zinc–air system

Cited by 22 publications

References 21 publications

The study of structural, morphological and optical properties of (Al, Ga)-doped ZnO: DFT and experimental approaches

The study of structural, morphological and optical properties of (Al, Ga)-doped ZnO: DFT and experimental approaches

Boosting light-driven CO2 reduction into solar fuels: Mainstream avenues for engineering ZnO-based photocatalysts

Basic Characteristics of Hemimorphite and Its Transformation Mechanism with Na2CO3

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