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Farha AH, Al Naim AF, Mansour SA. Cost-Effective and Efficient Cool Nanopigments Based on Oleic-Acid-Surface-Modified ZnO Nanostructured. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2159. [PMID: 36984039 PMCID: PMC10051544 DOI: 10.3390/ma16062159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
In this paper, as-synthesized and oleic acid (OA)-surface-treated zinc oxide (ZnO) nanocrystals were successfully synthesized and investigated for cool-nanopigment applications. ZnO nanocrystals were synthesized using the thermal decomposition method. The OA-surface-treated ZnO sample was obtained with an OA:ZnO ratio of 1:1. The structural, optical and morphological properties of the samples were characterized via X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-VIS-NIR diffused reflectance spectroscopy (DRS) and field-emission scanning electron microscopy (FE-SEM) techniques. ZnO nanocrystals possess a well-known zincate phase of ZnO, as confirmed for the as-synthesized sample with a reduction in the integrity of the ZnO crystalline structure upon the application of the OA coating. XRD peaks broadening and decreasing in crystallite size were obtained upon the surface modification of the ZnO by OA. The average crystallite size decreased from 31.5 to 17.4 nm, and the surface area changed from 23.37 to 7.48 m2/g upon OA treatment. These changes were attributed to the well-capping of the ZnO nanoparticles by OA, and, furthermore, OA increased the dispersion of the nanoparticles. The optical band gap of the investigated samples demonstrated a blue shift from 3.06 eV to 3.22 eV upon treatment. Both samples showed high NIR reflectance (RNIR∗) values, which makes them well qualified for use as cool nanopigments. Additionally, the as-synthesized sample showed an RNIR∗ value higher than that of the treated sample.
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Affiliation(s)
- Ashraf H. Farha
- Department of Physics, College of Science, King Faisal University, Al Ahsa 31982, Saudi Arabia;
- Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
| | - Abdullah F. Al Naim
- Department of Physics, College of Science, King Faisal University, Al Ahsa 31982, Saudi Arabia;
| | - Shehab A. Mansour
- Basic Engineering Science Department, Faculty of Engineering, Menoufia University, Shebin El-Kom 32551, Egypt;
- Advanced Materials/Solar Energy and Environmental Sustainability (AMSEES) Laboratory, Faculty of Engineering, Menoufia University, Shebin El-Kom 32551, Egypt
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Chen Y, Guo W, Huang Y, Chang Y, Wei Z, Jiang J, Boulet P, Record MC. Preparation and Chromaticity Control of CoTiO 3/NiTiO 3 Co-Coated TiO 2 Composite Pigments. MATERIALS 2022; 15:ma15041456. [PMID: 35207996 PMCID: PMC8875539 DOI: 10.3390/ma15041456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 02/01/2022] [Accepted: 02/10/2022] [Indexed: 01/27/2023]
Abstract
In this study, home-made amorphous TiO2 microspheres with good mono-dispersity and large numbers of mesopores on the surface were used as substrates. The intermediate microspheres were obtained by adding Co/Ni sources with different Co/Ni molar ratios in a water bath and making them react by water bath heating. By calcining the intermediate microspheres deposited on the TiO2 ones, a core–shell structured spherical CoTiO3/NiTiO3 inorganic composite pigment was prepared. The synthesized pigments were characterized by X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), laser particle size (LPS) analysis and colorimetry. The results show that when the calcination temperature is 800 °C and the Co/Ni molar ratio is 0.5:0.5, the pigments consist of a TiO2 core and outer ilmenite CoTiO3/NiTiO3 shell. Moreover, the surface of the product microspheres is smooth, and the particles are of regular sphericity with a uniform particle size of about 1.8 μm. The colorimetric analysis from the samples calcined at 800 °C shows color changes from yellow-green to dark green as the Co/Ni molar ratio increases (0.1:0.9 to 0.9:0.1). A Co/Ni molar ratio that is too high or too low results in the formation of by-products such as Co3O4 or NiO, respectively, which adhere to the product surface and affect the chromaticity of the product. This work has enabled the chromatic modulation of yellow-green inorganic pigments, providing a solution for the preparation of spherical inorganic pigments that are more suitable for industrial inkjet printing.
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Affiliation(s)
- Yuan Chen
- Hubei Provincial Key Laboratory of Green Light Industrial Materials, Hubei University of Technology, Wuhan 430068, China; (Y.C.); (Y.C.); (Z.W.); (J.J.)
- Collaborative Innovation Center for Green Lightweight Materials and Processing, Hubei University of Technology, Wuhan 430068, China
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
| | - Wei Guo
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
| | - Yuan Huang
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
| | - Ying Chang
- Hubei Provincial Key Laboratory of Green Light Industrial Materials, Hubei University of Technology, Wuhan 430068, China; (Y.C.); (Y.C.); (Z.W.); (J.J.)
- Collaborative Innovation Center for Green Lightweight Materials and Processing, Hubei University of Technology, Wuhan 430068, China
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
| | - Zhishun Wei
- Hubei Provincial Key Laboratory of Green Light Industrial Materials, Hubei University of Technology, Wuhan 430068, China; (Y.C.); (Y.C.); (Z.W.); (J.J.)
- Collaborative Innovation Center for Green Lightweight Materials and Processing, Hubei University of Technology, Wuhan 430068, China
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
| | - Jiuxin Jiang
- Hubei Provincial Key Laboratory of Green Light Industrial Materials, Hubei University of Technology, Wuhan 430068, China; (Y.C.); (Y.C.); (Z.W.); (J.J.)
- Collaborative Innovation Center for Green Lightweight Materials and Processing, Hubei University of Technology, Wuhan 430068, China
- School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; (W.G.); (Y.H.)
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
| | - Pascal Boulet
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
- MADIREL, CNRS, Faculty of Sciences, Aix-Marseille University, CEDEX 20, 13397 Marseille, France
| | - Marie-Christine Record
- New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base, Wuhan 430068, China;
- IM2NP, CNRS, Faculty of Sciences, Aix-Marseille University, CEDEX 20, 13397 Marseille, France
- Correspondence:
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Effects of Ambience on Thermal-Diffusion Type Ga-doping Process for ZnO Nanoparticles. COATINGS 2022. [DOI: 10.3390/coatings12010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Various annealing atmospheres were employed during our unique thermal-diffusion type Ga-doping process to investigate the surface, structural, optical, and electrical properties of Ga-doped zinc oxide (ZnO) nanoparticle (NP) layers. ZnO NPs were synthesized using an arc-discharge-mediated gas evaporation method, followed by Ga-doping under open-air, N2, O2, wet, and dry air atmospheric conditions at 800 °C to obtain the low resistive spray-coated NP layers. The I–V results revealed that the Ga-doped ZnO NP layer successfully reduced the sheet resistance in the open air (8.0 × 102 Ω/sq) and wet air atmosphere (8.8 × 102 Ω/sq) compared with un-doped ZnO (4.6 × 106 Ω/sq). Humidity plays a key role in the successful improvement of sheet resistance during Ga-doping. X-ray diffraction patterns demonstrated hexagonal wurtzite structures with increased crystallite sizes of 103 nm and 88 nm after doping in open air and wet air atmospheres, respectively. The red-shift of UV intensity indicates successful Ga-doping, and the atmospheric effects were confirmed through the analysis of the defect spectrum. Improved electrical conductivity was also confirmed using the thin-film-transistor-based structure. The current controllability by applying the gate electric-field was also confirmed, indicating the possibility of transistor channel application using the obtained ZnO NP layers.
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Promising Cr-Doped ZnO Nanorods for Photocatalytic Degradation Facing Pollution. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app12010034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chromium (Cr)-doped zinc oxide (ZnO) nanorods with wurtzite hexagonal structure were prepared through a thermal decomposition technique. The concentration effect of the Cr doping on the structural, morphological, and optical properties of the ZnO nanorods was established by correlating various measurements: transmission electron microscopy (TEM), photoluminescence (PL), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and several UV-visible studies. The obtained nanorods were investigated as photocatalysts for the photodegradation process of methyl orange (MO), under UV-vis light illumination. Different weights and time intervals were studied. A 99.8% photodegradation of MO was obtained after 100 min in the presence of 1 wt.% Cr III acetate hydroxide and zinc acetate dehydrate “ZnO-Cr1”. The kinetic rate constant of the reaction was found to be equal to 4.451 × 10−2 min−1 via a pseudo-first order rate model. Scavenger radicals demonstrated the domination of OH• radicals by those of O2•− superoxide species during the photodegradation. The interstitial oxygen site Oi is proposed to play a key role in the generation of holes in the valence band under visible irradiation. The ZnO-Cr1 photocatalyst displayed good cycling stability and reusability.
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