Готові списки джерел за темами / ZnCo2O4

Добірка наукової літератури з теми "ZnCo2O4"

Автор: Grafiati
Опубліковано: 6 вересня 2023

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Статті в журналах з теми "ZnCo2O4"

1

Wang, Jinjin, Tianfeng Ye, Yanqun Shao, Zhiyuan Lu, Yuting Lin, Huixuan Wu, Guoyong Li, Kongfa Chen, and Dian Tang. "Flower-Like Nanostructured ZnCo2O4/RuO2 Electrode Materials for High Performance Asymmetric Supercapacitors." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 120553. http://dx.doi.org/10.1149/1945-7111/ac42a4.

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Анотація:
RuO2 is well known to be an active and expensive metal oxide. In the paper, ZnCo2O4/RuO2 nanocomposites were synthesized by simple hydrothermal, impregnation and calcination methods. Due to the multifunctional bridge structure, RuO2 could not only effectively inhibit the volume change of ZnCo2O4 in long-term work but also provide more redox active sites. The forbidden bandwidth was reduced and the conductivity was improved after doping RuO2. Compared with ZnCo2O4, the density of state of ZnCo2O4/RuO2 tended to a higher energy level. ZnCo2O4/3 wt% RuO2 electrode exhibited an excellent specific capacitance (1346.56 F g−1) and cyclic stability in 6 M KOH aqueous solution. For the first time, the electrochemical performance of ZnCo2O4/RuO2//IrO2-ZnO ASC has been evaluated in two-electrode configurations. The supercapacitor exhibited an excellent energy density of 40.89 W h kg−1 at the power density of 740 W kg−1 and a high capacitance retention of 87.5% even after 7000 cycles at a scanning rate of 100 mV s−1. The ZnCo2O4/RuO2 was a promising electrode material for supercapacitors.
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2

Kim, Hyun Jung, In Chang Song, Jae Ho Sim, Hyo Jin Kim, Do Jin Kim, Young Eon Ihm, and Woong Kil Choo. "Effect of Growth Condition on the Electrical and Magnetic Properties of Sputtered ZnCo2O4 Films." Materials Science Forum 449-452 (March 2004): 509–12. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.509.

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Анотація:
We report on the effect of the oxygen partial pressure ratio in the sputtering gas mixture on the electrical and magnetic properties of cubic spinel ZnCo2O4 thin films grown by reactive magnetron sputtering. The conduction type and carrier concentration in ZnCo2O4 films were found to be dependent on the oxygen partial pressure ratio. The maximum electron and hole concentration at 300 K were estimated to be as high as 1.37 × 1020 cm-3 and 2.81 × 1020 cm-3, respectively. While an antiferromagnetic coupling was found for n-type ZnCo2O4, a ferromagnetic interaction was observable in p-type ZnCo2O4, indicating hole-induced ferromagnetic transition in spinel ZnCo2O4.
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3

Rajesh, John, and Kwang-Soon Ahn. "Facile Hydrothermal Synthesis and Supercapacitor Performance of Mesoporous Necklace-Type ZnCo2O4 Nanowires." Catalysts 11, no. 12 (December 13, 2021): 1516. http://dx.doi.org/10.3390/catal11121516.

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In this work, mesoporous ZnCo2O4 electrode material with necklace-type nanowires was synthesized by a simple hydrothermal method using water/ethylene glycol mixed solvent and subsequent calcination treatment. The ZnCo2O4 nanowires were assembled by several tiny building blocks of nanoparticles which led to the growth of necklace-type nanowires. The as-synthesized ZnCo2O4 nanowires had porous structures with a high surface area of 25.33 m2 g−1 and with an average mesopore of 23.13 nm. Due to the higher surface area and mesopores, the as-prepared necklace-type ZnCo2O4 nanowires delivered a high specific capacity of 439.6 C g−1 (1099 F g−1) at a current density of 1 A g−1, decent rate performance (47.31% retention at 20 A g−1), and good cyclic stability (84.82 % capacity retention after 5000 cycles). Moreover, a hybrid supercapacitor was fabricated with ZnCo2O4 nanowires as a positive electrode and activated carbon (AC) as a negative electrode (ZnCo2O4 nanowires//AC), which delivered an energy density of 41.87 Wh kg−1 at a power density of 800 W kg−1. The high electrochemical performance and excellent stability of the necklace-type ZnCo2O4 nanowires relate to their unique architecture, high surface area, mesoporous nature, and the synergistic effect between Zn and Co metals.
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4

Narasimharao, Katabathini, Mohamed Mokhtar M. Mostafa, Zahra M. Al-Amshany, and Wejdan Bajafar. "Mechanochemical Synthesized CaO/ZnCo2O4 Nanocomposites for Biodiesel Production." Catalysts 13, no. 2 (February 13, 2023): 398. http://dx.doi.org/10.3390/catal13020398.

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Анотація:
Biodiesel has been recognized as an environmentally friendly, renewable alternative to fossil fuels. In this work, CaO/ZnCo2O4 nanocomposites were successfully synthesized via simple mechanochemical reaction between ZnCo2O4 and CaO powders by varying the CaO loading from 5 to 20 wt.%. The synthesized materials were found to be highly efficient heterogeneous catalysts for transesterification of tributyrin with methanol to produce biodiesel. The nanocomposite, which contained 20 wt.% CaO and 80 wt.% ZnCo2O4 (CaO/ZnCo2O4-20), exhibited superior and stable transesterification activity (98% conversion) under optimized reaction conditions (1:12 TBT to methanol molar ratio, 5 wt.% catalyst and 180 min. reaction time). The experimental results revealed that the reaction mechanism on the CaO/ZnCo2O4 composite followed pseudo first-order kinetics. The physicochemical characteristics of the synthesized nanocomposites were measured using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Fourier-transformed infrared spectroscopy (FTIR), X-ray photoelectron spectrometer (XPS), N2-physisorption, and CO2- temperature-programmed desorption (CO2-TPD) techniques. The results indicated the existence of coalescence between the CaO and ZnCo2O4 particles, Additionally, the CaO/ZnCo2O4-20 catalyst was found to possess the greater number of highly basic sites and high porosity, which are the key factors affecting catalytic performance in transesterification reactions.
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5

Lin, En-Syuan, Feng-Sheng Chao, Chen-Jui Liang, Chi-Jung Chang, Alex Fang, Chung-Kwei Lin, Yu-Cheng Chang, Chien-Yie Tsay, Jerry J. Wu, and Chin-Yi Chen. "Hydrothermal Synthesis of Co3O4/ZnCo2O4 Core-Shell Nanostructures for High-Performance Supercapacitors." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 123502. http://dx.doi.org/10.1149/1945-7111/ac3a27.

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Анотація:
Supercapacitive properties of Co/ZnCo oxide composite with a core–shell nanostructure (Co3O4/ZnCo2O4) prepared directly onto a nickel foam substrate by a two-step hydrothermal method were investigated. The synthesized core–shell structure consisted of some ∼40–100 nm in thick flaky ZnCo2O4 deposits coated onto the surface of Co3O4 nanorods measuring ∼150 nm in diameter. The specific capacitance value of the Co3O4/ZnCo2O4 core–shell nanostructure synthesized by hydrothermal at 130 °C for a ZnCo2O4 deposition time of 2 h can attain 1804 F g−1 at a scan rate of 5 mV s−1. Furthermore, the core–shell structured electrode still exhibited a relatively good capacitance retention of more than 93% after 3000 CV cycles due to the superior structural support of Co3O4 scaffolds. The Co3O4/ZnCo2O4 core–shell structure exhibits excellent electrochemical performances and, as such, is one of the more promising active materials in pseudocapacitor applications.
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6

Yang, Qianqian, Yifei Xu, Xiaodong Xue, Ning Zhang, Rui Feng, Meng Sun, Tao Yan, and Liangguo Yan. "Constructing an efficient ZnCo2O4/ZnIn2S4 composite with boosted visible-light photocatalytic hydrogen evolution." Materials Express 12, no. 3 (March 1, 2022): 426–34. http://dx.doi.org/10.1166/mex.2022.2059.

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Анотація:
Herein, a novel ZnCo2O4/ZnIn2S4 composite was prepared through a novel one-pot refluxing wet chemistry process successfully. The phase structure, micro morphology and optical properties of photocatalyst were analyzed through XRD, SEM, XPS and UV-vis spectroscopy. The photocatalysis of the prepared specimens were assessed by the photocatalytic hydrogen evolution with visible-light (λ > 420 nm). Consequently, the ZnCo2O4/ZnIn2S4 photocatalyst displayed better photocatalysis than the original constituents for hydrogen evolution. Moreover, the corresponding maximized hydrogen production rate of ZnCo2O4/ZnIn2S4 composite loaded with 15% ZnCo2O4 was 3713.4 μmol · h−1 · g−1, which registered approximately 10.2 folds higher than pristine ZnIn2S4. Moreover, the ZnCo2O4/ZnIn2S4 composite manifested superior stability during the photocatalytic reactions. In addition, the underlying mechanism for the outstanding performance of hydrogen production was revealed as well. This research offers inspiration for the rational creation of high-efficiency photocatalytic agents for hydrogen evolution.
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7

Aruchamy, Kanakaraj, Athinarayanan Balasankar, Subramaniyan Ramasundaram, and Tae Hwan Oh. "Recent Design and Synthesis Strategies for High-Performance Supercapacitors Utilizing ZnCo2O4-Based Electrode Materials." Energies 16, no. 15 (July 25, 2023): 5604. http://dx.doi.org/10.3390/en16155604.

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Анотація:
ZnCo2O4 has emerged as a promising electrode material for supercapacitor applications due to its unique properties and potential for high-performance energy storage. As a transition metal oxide, ZnCo2O4 offers eco-friendly characteristics and favorable diffusion properties, making it an attractive candidate for sustainable energy storage systems. However, the poor conductivity and low surface area of ZnCo2O4 have posed challenges for its optimal utilization in supercapacitors. Various innovative approaches have been explored to overcome these limitations, including the development of ZnCo2O4 with different morphologies such as core-shell and porous structures. This review work aims to provide a comprehensive analysis of diverse synthesis methods employed in recent studies, including hydrothermal growth, solvothermal synthesis, wet chemical methods, and miscellaneous synthesis techniques, each offering unique advantages and influencing the properties of the synthesized materials. The synthesis conditions, such as precursor concentrations, temperature, annealing time, and the incorporation of dopants or additional materials, were found to play a crucial role in determining the electrochemical performance of ZnCo2O4-based supercapacitor electrodes. Core-shell heterostructures based on ZnCo2O4 exhibited versatility and tunability, with the choice of shell material significantly impacting the electrochemical performance. The incorporation of different materials in composite electrodes, as well as doping strategies, proved effective in enhancing specific capacitance, stability, surface area, and charge transfer characteristics. Controlled synthesis of ZnCo2O4 with diverse morphologies and porosity was crucial in improving mechanical strength, surface area, and ion diffusion capabilities. The findings provide valuable insights for the design and engineering of high-performance supercapacitor electrodes based on ZnCo2O4, and suggest exciting avenues for further exploration, including advanced characterization techniques, novel doping strategies, scale-up of synthesis methods, and integration into practical supercapacitor devices. Continued research and development in this field will contribute to the advancement of energy storage technologies and the realization of efficient and sustainable energy storage systems.
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8

Zhao, Wenjia, Zhaoping Shi, Yongbing Qi, and Jipeng Cheng. "The Carbon-Coated ZnCo2O4 Nanowire Arrays Pyrolyzed from PVA for Enhancing Lithium Storage Capacity." Processes 8, no. 11 (November 20, 2020): 1501. http://dx.doi.org/10.3390/pr8111501.

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In this paper, ZnCo2O4 nanowire arrays with a uniform carbon coating were introduced when polyvinyl alcohol (PVA) served as the carbon source. The coating process was completed by a facile bath method in PVA aqueous solution and subsequent pyrolyzation. The PVA-derived carbon-coated ZnCo2O4 nanowire array composites can be used directly as the binder-free and self-supported anode materials for lithium-ion batteries. In the carbon-coated ZnCo2O4 composites, the carbon layer carbonized from PVA can accelerate the electron transfer and accommodate the volume swing during the cycling process. The lithium storage properties of the carbon-coated ZnCo2O4 composites are investigated. It is believed that the novel carbon-coating method is universal and can be applied to other nanoarray materials.
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9

Chang, Xin, Xiangyang Xu, Zhifeng Gao, Yingrui Tao, Yixuan Yin, Guangyu He, and Haiqun Chen. "Activation of persulfate by heterogeneous catalyst ZnCo2O4–RGO for efficient degradation of bisphenol A." Canadian Journal of Chemistry 98, no. 12 (December 2020): 771–78. http://dx.doi.org/10.1139/cjc-2020-0192.

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Анотація:
A nanocomposite, reduced graphene oxide (RGO) modified ZnCo2O4 (ZnCo2O4–RGO) was synthesized via one-step solvothermal method for activating persulfate (PS) to degrade bisphenol A (BPA). The morphology and structure of the nanocomposite were identified by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. RGO provides nucleation sites for ZnCo2O4 to grow and inhibits the agglomeration of the nanoparticles. The influence of different reaction conditions on the oxidation of BPA catalyzed by ZnCo2O4–RGO was investigated, including the content of RGO, the dosage of catalyst, the concentration of humic acid (HA), anions in the environment, the reaction temperature, and pH. BPA can be totally degraded within 20 min under optimized reaction conditions. The presence of HA, Cl−, and NO3− only has a slight effect on the oxidation of BPA, whereas the presence of either H2PO4− or HCO3− can greatly inhibit the reaction. ZnCo2O4–RGO shows good cycling stability and practical application potential. A reaction mechanism of the degradation of BPA was also explored.
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10

Li, Wang, Yulin Guo, Yan Liu, Wen Yang, Jifan Hu, and Jiangwei Ma. "A controllable surface etching strategy for MOF-derived porous ZnCo2O4@ZnO/Co3O4 oxides and their sensing properties." RSC Advances 13, no. 36 (2023): 24936–43. http://dx.doi.org/10.1039/d3ra05135h.

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Анотація:
A surface etching strategy was proposed for the controllable synthesis of MOF-derived ZnCo2O4@ZnO/Co3O4 oxides, and the ZnCo2O4@ZnO/Co3O4-6 h sensor device exhibits the highest response and excellent selectivity to 100 ppm methanal at 200 °C.
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Більше джерел

Дисертації з теми "ZnCo2O4"

1

Schein, Friedrich-Leonhard, Markus Winter, Tammo Böntgen, Wenckstern Holger von, and Marius Grundmann. "Highly rectifying p-ZnCo2O4/n-ZnO heterojunction diodes." American Institute of Physics, 2014. https://ul.qucosa.de/id/qucosa%3A31194.

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Анотація:
We present oxide bipolar heterojunction diodes consisting of p-type ZnCo2O4 and n-type ZnO fabricated by pulsed-laser deposition. Hole conduction of ZnCo2O4 (ZCO) was evaluated by Hall and Seebeck effect as well as scanning capacitance spectroscopy. Both, ZCO/ZnO and ZnO/ZCO type heterostructures, showed diode characteristics. For amorphous ZCO deposited at room temperature on epitaxial ZnO/Al2O3 thin films, we achieved current rectification ratios up to 2x1010, ideality factors around 2, and long-term stability.
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2

Bieber, Herrade. "Couches minces de ZnCoO déposées par ablation laser pulsée : effet de dopage sur les propriétés structurales et magnétiques." Strasbourg, 2009. http://www.theses.fr/2009STRA6134.

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Анотація:
Cette étude s'inscrit dans le domaine de l'électronique de spin, qui combine à la fois la charge et le spin de l'électron pour la réalisation de nouveaux dispositifs notamment ceux visant le stockage d'information. Jusqu’à présent, la réalisation de ces dispositifs pour l’électronique de spin a été freinée par la problématique de l’injection d’électrons avec une direction de spin contrôlée dans un semi-conducteur. En effet l'injection d'électrons polarisés en spin à partir d'un métal ferromagnétique vers un semi-conducteur est limitée par la différence de résistivité entre ces deux matériaux. Une solution a été de rendre le semi-conducteur ferromagnétique. Pour cela, une partie des ions de la matrice semi-conductrice non magnétique est remplacée par des ions magnétiques. L'oxyde de zinc dopé au cobalt est un candidat prometteur, car il lui est prédit dans le cas de la présence de porteurs de charge libres une température de Curie supérieure à la température ambiante. Néanmoins, l'origine de ce ferromagnétisme observée dans la littérature reste controversée. Nous avons donc étudié ZnCoO sous forme de couches minces déposées par ablation laser pulsée. L'étude s'est ensuite focalisée sur l'influence sur les propriétés structurales et magnétiques de la polarité des porteurs de charge par un dopage supplémentaire à l'aluminium et à l'argent. Nous avons pu mettre en évidence l'importance des défauts dans le mécanisme du ferromagnétisme observé à température ambiante dans les couches minces de ZnCoO
The combination of the charge and the spin of the electron giving rise to the new field of spintronics, has led to the realization of new devices amongst others in the field of data storage. Till now, the major difficulty to realize such devices was to obtain spin injection of controlled spin direction into a semi-conductor. Indeed the spin injection from a ferromagnetic metal into a semi-conductor is restrained by the difference of resistivity in both materials. One solution consisted in making the semi-conductor ferromagnetic. Such diluted magnetic semi-conductors (DMS) are composed of a semi-conducting matrix, in which a part of the ions is replaced by magnetic ions. Co-doped zinc oxide is a promising DMS, as it is predicted a Curie temperature above room temperature for this material when doped with transition metals thus giving additional charge carriers. Nevertheless, the origin of the observed ferromagnetism in literature remains controversial. We have thus studied thin films of ZnCoO deposited by pulsed laser deposition. The study has then been focused on the influence of the polarity of charge carriers on the structural and magnetic properties of the thin films by additional doping with silver and aluminum. We have evidenced the importance of the presence of defects on the origin of the observed ferromagnetism in the thin films
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3

Ben, Mahmoud Aroussi. "Ingénierie des défauts dans les matériaux semi-conducteurs II-VI : application aux semi-conducteurs photoréfractifs ZnCdTe:V et aux semi-conducteurs magnétiques ZnMnO et ZnCoO." Paris 6, 2006. http://www.theses.fr/2006PA066596.

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Анотація:
ZnCdTe et le ZnTMO (TM = métaux de transition 3d) sont des matériaux photoréfractifs et ferromagnétiques dont les propriétés sont liées à la présence de défauts. Nous avons étudié le rôle du dopant Vanadium dans ZnCdTe pour les propriétés photoréfractives. Nous avons également montré le rôle important d’un défauts intrinsèque, natif que nous attribuons à l’antisite de Te. Les propriétés magnétiques des couches minces de ZnMnO ont été étudiées pour des concentrations Mn (0. 01 < x < 0. 34). Nos résultats montrent clairement le caractère antiferromagnétique des interactions Mn-Mn. Ils contredisent les publications récentes d’un état ferromagnétique intrinsèque. Par contre, nous avons observé des faibles interactions ferromagnétiques dans des couches dopées à x = 0. 03, résultats interprétés dans un modèle de polaron magnétique. L’étude par spectroscopie RPE des couches ferromagnétiques de ZnCoO avec [Co] = 0. 25 nous a permis d’associer l’état FM à la présence des nanoclusters métalliques
Bulk ZnCdTe crystals and ZnTMO (TM = 3d transition metal) thin films are promising photorefractive and magnetic materials respectively with defect mediated properties. We have studied the role of V doping for the properties of ZnCdTe and their modification by an intrinsic, native defect. The intrinsic defect previously attributed to the Te vacancy is assigned to a Te antisite. Recent predictions of high temperature ferromagnetism (FM) in ZnO:(Mn, Co) have been tested by EPR spectroscopy. Our results for n-type (1018cm−3) Zn1−xMnxO ( 0. 01< x < 0. 34 ) films grown by MOCVD show intrinsic AF interactions only. They contradict recent claims of intrinsic high temperature FM in this system. In the narrow concentration range x 􀀀 0. 03, FM interactions have been observed and modelled by a magnetic polaron effect. The EPR study of ferromagnetic, highly doped ZnCoO films with [Co] = 0. 25 grown by PLD allows us to assign the FM to the presence of metallic nanoclusters apparently not detectable in XRD. Titre
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4

Chen, Po-Chun, and 陳柏均. "The characterization of sol-gel derived ZnCo2O4 thin films." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9x5a3w.

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Анотація:
碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
105
In this study, the ZnCo2O4 thin films were prepared on quartz and glass substrate by sol-gel method. The sol-gel derived thin films were annealed at 300~400℃ in O2 for 2 hours. Single ZnCo2O4 phase exists at 300~400℃ with both substrates. For the quartz substrate , the optical bandgap of thin films is 2.47~2.50 eV with the maximum transmittance of 80% . For the glass substrate, the optical bandgap of thin films is 2.41~2.42 eV with the maximum transmittance of 55%. The thickness of the ZnCo2O4 thin films was about 120 nm. Three Raman vibration modes including Eg, F2g and A1g were found in the ZnCo2O4 thin films. The best electrical resistivity of the ZnCo2O4 thin films was found at the annealed specimen at 3500C.The electrical conductivity of the ZnCo2O4 thin films was 19.71±0.26 Ωcm. Using the same method to prepared the Mg-doped ZnCo2O4 thin films on the glass substrate is also provided. The optical bandgap of thin films is 2.31~2.47 eV with the maximum transmittance of 55% . The electrical resistivity of the Mg-doped ZnCo2O4 thin films was reduced to 82.85% compare to the thin films without Mg-dopant. The best electrical properties of the thin films occurs at 5%-Mg doping was 3.38±1.42 Ωcm. Keywords: sol-gel method, ZnCo2O4 , thin films, Mg-doped
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5

Lai, Ting-Yu, and 賴亭羽. "Preparation of NiCo2O4/ZnCo2O4 composite and its application on supercapacitors." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/xbx47h.

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Анотація:
碩士
國立中興大學
化學工程學系所
106
Binary transition metal oxides of spinel structure with high active area, high porosity and excellent electrochemical performance have been applied on electrode materials for supercapacitors in recent years. In order to obtain more superior electrochemical properties, it begins to develop toward the composite material, and the structural characteristics of two different materials are combined to increase the specific surface area, promote the transport capability of the electrons, and further enhance the electrochemical performance of supercapacitors. The study includes two parts, in part I, NiCo2O4 with different concentrations were synthesized via hydrothermal method and applied to electrode materials for supercapacitors. X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscope (FE-SEM) were used to analyze the crystal structure, surface element composition and surface morphology, respectively. The galvanostatic charge-discharge and cyclic voltammetry tests were performed in 2 M KOH solution to compare the electrochemical properties of NiCo2O4 with different concentrations. Among them, NCO-3 exhibited better specific capacitance, and conducted to part II with this result. In part II, NiCo2O4/ZnCo2O4 were synthesized via hydrothermal method and applied to electrode materials for supercapacitors. X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscope (FE-SEM) were used to analyze the crystal structure, surface element composition and surface morphology, respectively. The galvanostatic charge-discharge and cyclic voltammetry tests were performed in 2 M KOH solution to compare the electrochemical properties of NiCo2O4/ZnCo2O4 with different concentrations. The NCO/ZCO-4 exhibited the high specific capacitance of 1369.3 F g-1 at a current density of 1 A g-1. In addition, after 1000 continuous charge-discharge cycles at a high current density of 16 A g-1, the NCO/ZCO-4 remained symmetrical and reversible curves. It both had outstanding rate capability and superior cycling stability. The results of above analysis demonstrated that NiCo2O4/ZnCo2O4 was a promising electrode material for supercapacitors.
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6

ZHAM, MING-HAN, and 詹明翰. "Microstructure and Optoelectronic Properties of ZnCo2O4 Thin Films Prepared by Sol-Gel Processing." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ezrjx2.

Повний текст джерела
Анотація:
碩士
亞洲大學
光電與通訊學系
106
In this study, the effects of amorphous Zn-Co-O and spinel ZnCo2O4 on the photoelectric properties were investigated. The film was annealed at 250 °C to form a single crystallite ZnCo2O4. Annealing temperature was higher than 350 °C to enhance the crystallinity. ZnCo2O4 film had nano-grain, and the surface morphology was polygonal with irregular shaped. With the annealing temperatures increase, which the films’ nano-grain and polygonal microstructure sizes increase. The root mean square value of the amorphous Zn-Co-O film was 0.58 nm, and the RMS values of the ZnCo2O4 film annealed between 250 and 600 °C were 0.65~7.34 nm. The light transmittance has a red-shift phenomenon. Absorption coefficient curve of the spinel ZnCo2O4 film exhibits a characteristic absorption peak at about 400 nm, and the absorption peak becomes more obvious with the increasing of crystallinity. The ZnCo2O4 film had band gaps between 4.14 and 4.19 eV. Analytical composition of Zn, Co and O was 14.35: 27.65: 57.99 at%, which was in accordance with the ZnCo2O4 chemical formula of 1:2:4. The film annealed at 300 °C had the lowest resistivity of 8.22 Ω-cm, and also had the highest carrier concentration of 2.98 x 1018 cm-3, and the energy gap value was 4.14 eV.
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7

DAI, WEI-ZHI, and 戴瑋志. "Preparation of sol-gel derived Ni-doped ZnCo2O4 thin films and their optoelectronic properties." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/76tfrt.

Повний текст джерела
Анотація:
碩士
國立高雄科技大學
化學工程與材料工程系
107
In this study, the Ni-doped ZnCo2O4 thin-films prepared by sol-gel method. The precursor solution was coated on glass substrate by a spin coating method, the were annealed at 400°C for 2 hours under an oxygen. The XRD results, ZnCo2O4 phase can be successfully prepared by Ni-doping 0%~120%. The 150% is ZnCo2O4 and NiO phases. The additional 180% and 200% was converted to pure NiO phases. the lattice constant of condition were calculated according to phases, and that found Ni-doping causes size change.The surface morphology of the surface was observed by FE-SEM. The Ni-doped 0%~150% were dense and flat surfaces, and 180% and that 200% were found to be cracked due to poor coating. According to UV-vis analysis, the maximum transmittance of Ni-doped 0%~120% visible light region were about 30~56%, and the band gap respectively of 2.33eV~2.53eV and 3.61eV~3.90eV. The Ni-doped 150%~200% were the Optical characteristics of NiO the maximum penetration to 60~65%, and the band gap of 4.01eV~4.04eV. In addition, the ZnCo2O4 phase has a high conductivity in Ni-doping 70%~120%, and the best electrical conductivity of Ni-doped 90% was carrier concentration (1.24±0.19)1018 cm-3, and the resistance was 3.39±0.01 Ωcm, and the conductivity was (2.95±0.01)10-1 S/cm.Finally, the conditions of Ni-doped 1%~100% were analyzed by X-ray photoelectron spectroscopy. It was found that the 3+ ion content of Co 2p3/2 and Ni 2p3/2 orbital affected the amount of anti-site defects, which made Majority carriers The quantity changes and affects the electrical properties. The Zn 2p and O1s orbital show characteristic of ZnCo2O4.
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8

SU, YU-ZHAN, and 蘇于展. "Effects of Ca/Ni doping on the structural and optoelectronic properties of ZnCo2O4 thin films." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/gpd39c.

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Анотація:
碩士
亞洲大學
光電與通訊學系
107
In this study, in order to improve the material properties of spinel ZnCo2O4 thin films, the electrical properties of semiconductors were enhanced by extrinsic doping. We studied the crystal structure, microstructure, photoelectric properties and antibacterial properties of doping effects on the ZnCo2O4. The content ratio of Zn(Co1-xNix)2O4 doping increased from Nix=0 to 0.30, and nickel-doped ZnCo2O4 film maintained a single-phase spinel oxide, and no nickel-related secondary phase structure formed. The replacement of cobalt by nickel causes decreasing effect on the atomic lattice order, resulting in a decrease in the average grain size and a reduction in the roughness of the surface. Both grain size and surface roughness affect the transmittance of the film. The material has translucent optical properties. The transmittance of all films was about 22% ~ 38% at 550nm, and the characteristic peak of absorption was about 400nm. At a higher nickel doping content Nix=0.20 ~ 0.30, the absorption characteristic peak gradually disappears. The direct band gap of the un-doped ZnCo2O4 film was 2.50 eV, and the band gaps of the nickel-doped ZnCo2O4 were 2.45~2.57 eV. All films are p-type semiconductors, and positive divalent nickel can replace positive trivalent cobalt to increase the carrier concentration, resulting in a decrease in resistivity from 312.5 Ω-cm (Nix = 0) to 15.7 Ω-cm (Nix = 0.30). Escherichia coli and Staphylococcus aureus cannot breed and survive on the film, the antibacterial rate of the material can reach more than 99%, Ni-doped ZnCo2O4 has excellent application potential. For Zn(Co1-xCax)2O4 films, the doping content ratios of Cax were from 0.00 to 0.20, no impurity phase formed in all spinel structure films. The surface had cell-like microstructure. Surface roughness values increased at higher calcium doping contents, and made the grain sizes decreasing. These translucent ZnCo2O4 films had light transmissions of 47% to 58% at wavelength of 600 nm. The absorption characteristics of blue and ultraviolet light of ZnCo2O4 were decreasing as increasing in calcium doping contentin the films. The band gaps of Zn(Co1-xCax)2O4 films increased from 2.46 eV (Cax= 0.00) to 2.51eV (Cax= 0.15), and Ca+2 replaces Co+3 to increase the conductivity and carrier concentration. The optimal doping ratio was Cax= 0.07. The resistivity decreased from 270.5 to 15.4 Ω-cm, and the carrier concentration increased from 2.54 × 1015 to 6.25 × 10 17 cm -3. The anti-S. aureus and E. coli abilities of the films had more than 99% in the UV light irradiation and in the absence of any light source. The p-type Zn(Co1-xCax)2O4 film can be applied to the antibacterial and electronic component.
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9

HUANG, SIH-WEN, and 黃思文. "The Characterization of ZnCo2O4 Thin Films Doped with Li and Mg Using Sol-gel Process." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/49p7st.

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Анотація:
碩士
國立高雄科技大學
化學工程與材料工程系
107
In this study, the ZnCo2O4 thin films were prepared on glass substrate by sol-gel method. The spin coating derived thin films were annealed at 300℃ in O2 for 2 hours. In the case of the magnesium dopant, single phase of ZnCo2O4 was obtained. The surface and cross section of the film were observed by FE-SEM. The ZnCo2O4 doped with 4% magnesium had the dense morphology, and the thickness was about 107 nm. UV-Vis analysis shows that the maximum transmittance of the visible light region of the film is between 55-60%. The first optical energy gap of the film is between 2.21-2.39 eV, and the second is between 3.63-3.89 eV. According to the Hall effect analyzer the lowest resistivity is 6.59±3.06 Ωcm when the ZnCo2O4 doped with 4% magnesium, which is about 92% lower than that of the undoped magnesium film. Finally, it is verified by XPS that the highest concentration ratio of Co3+ when the doping magnesium content is 4%, which means that the most holes are generated to optimize the electrical properties. In the case of the lithium dopant, single phase of ZnCo2O4 was obtained. The surface and cross section of the film were observed by FE-SEM. The ZnCo2O4 doped with 10% lithium had the dense morphology, and the thickness was about 148 nm. UV-Vis analysis shows that the maximum transmittance of the visible light region of the film is between 25-35%. The first optical energy gap of the film is between 2.13-2.39 eV, and the second is between 3.70-3.89 eV. According to the Hall effect analyzer the lowest resistivity is 2.29±6.01 Ωcm, which is about 72% lower than that of the undoped lithium film. Finally, it is verified by XPS that the highest concentration ratio of Co3+ when the doping lithium content is 10%, which means that the most holes are generated to optimize the electrical properties.
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10

Liu, Chang, and 劉暢. "Rapid Nitrogen Doping and Carbon Deposition of ZnCo2O4 Lithium-ion Battery Anode via Atmospheric Pressure Plasma Jet." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/02856700310599255680.

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Анотація:
碩士
國立清華大學
材料科學工程學系
104
The main objective of this dissertation is to improve the electrochemical performances of ZnCo2O4 (ZCO) Li-ion anode material by nitrogen-doping and carbon deposition. As for nitrogen doping, two rapid methods, including hydrothermal to treat powder and atmospheric pressure plasma jet (APPJ) to modify the electrode, were used to dope nitrogen in the ZCO anode material. Via hydrothermal method, nitrogen was doped in the ZCO spinel lattice, while APPJ mainly activated and modified the electrode surface binding with the dangling bond. N-doped compounds were formed on the electrodes by hydrothermal and APP methods. The uniformity, chemical composition, and diffraction patterns were examined by electron probe microanalyzer (EPMA), X-ray photoelectron spectroscopy (XPS) and X-ray diffractometer (XRD). Nitrogen doping effectively improved electrochemical performance in cycling retention and the capacity at a current density of 1C. This study provides a rapid and inexpensive nitrogen doping processes to efficiently promote the electrochemical performance in ZCO anode. In addition, a special set-up of atmospheric pressure plasma jet generator was applied to deposit carbon on the electrode. Significant amounts of C(I) and C2 clusters were discovered using optical emission spectroscopy. After adding N2, the CN species appeared in the plasma, owing to C and N2 reaction during the plasma generation. The results from the field emission scanning electron microscope (FESEM) and X-ray photoelectron microscopy (XPS) reveal the change in surface morphology and chemical bonding by plasma treatment. After 20 times of Ar+N2 plasma treatment, a significant increment in cycling stability under 1000 mA/g was evident.
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Частини книг з теми "ZnCo2O4"

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Morán-Lázaro, Juan Pablo, Florentino López-Urías, Emilio Muñoz-Sandoval, Oscar Blanco-Alonso, Marciano Sanchez-Tizapa, Alejandra Carreon-Alvarez, Héctor Guillén-Bonilla, María de la Luz Olvera-Amador, Alex Guillén-Bonilla, and Verónica María Rodríguez-Betancourtt. "Synthesis Characterization of Nanostructured ZnCo2O4 with High Sensitivity to CO Gas." In Nanostructured Materials - Fabrication to Applications. InTech, 2017. http://dx.doi.org/10.5772/68043.

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Тези доповідей конференцій з теми "ZnCo2O4"

1

Christina Mary, A. Juliet, and A. Chandra Bose. "Electrochemical performance of ZnCo2O4 nanoparticle." In Proceedings of the International Conference on Nanotechnology for Better Living. Singapore: Research Publishing Services, 2016. http://dx.doi.org/10.3850/978-981-09-7519-7nbl16-rps-235.

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Mary, A. Juliet Christina, and A. Chandra Bose. "Facile synthesis of ZnCo2O4/rGO nanocomposite for effective supercapacitor application." In DAE SOLID STATE PHYSICS SYMPOSIUM 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4980326.

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3

Ng, Dickon, and Jia Li. "Cotton-Derived C-doped ZnCo2O4/ZnO for Efficient Visible Light Photocatalysis." In 4th Annual International Conference on Materials Science, Metal & Manufacturing (M3 2017). Global Science & Technology Forum (GSTF), 2017. http://dx.doi.org/10.5176/2251-1857_m317.19.

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Guo, Bingjun, Haicheng Xuan, Yangyang Hao, and Yuekui Xu. "Electrochemical deposition of ZnCO2O4 nanosheets on Ni foam for supercapacitor applications." In 2016 4th International Conference on Mechanical Materials and Manufacturing Engineering. Paris, France: Atlantis Press, 2016. http://dx.doi.org/10.2991/mmme-16.2016.193.

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Mary, A. Juliet Christina, S. Thilagavathi, and A. Chandra Bose. "Influence of different synthesis approach on ZnCo2O4 nanomaterial and its supercapacitor behavior." In DAE SOLID STATE PHYSICS SYMPOSIUM 2017. Author(s), 2018. http://dx.doi.org/10.1063/1.5029173.

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6

Kumar, Vijay, and C. R. Mariappan. "Electrochemical performance of spinel-type Ni doped ZnCo2O4 mesoporous rods as an electrode for supercapacitors." In INTERNATIONAL CONFERENCE ON NANOMATERIALS FOR ENERGY CONVERSION AND STORAGE APPLICATIONS: NECSA 2018. Author(s), 2018. http://dx.doi.org/10.1063/1.5035232.

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Iwamoto, W. A., P. G. Pagliuso, R. R. Urbano, C. Rettori, K. Samanta, P. Bhattacharya, R. Katiyar, et al. "Local and Global Magnetic properties of Zn1-xCoxO, ZnCo2O4 and Mn-doped GaAs thin films." In INTERMAG 2006 - IEEE International Magnetics Conference. IEEE, 2006. http://dx.doi.org/10.1109/intmag.2006.375641.

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Huang, P., C. Lai, C. Yang, H. Huang, T. Chin, C. Chen, M. Lan, H. Huang, and H. Bor. "Exchange bias between ZnCoO and IrMn." In INTERMAG 2006 - IEEE International Magnetics Conference. IEEE, 2006. http://dx.doi.org/10.1109/intmag.2006.374987.

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Zhang, K., Y. Zhang, Z. Zhang, Z. Zheng, J. Nan, G. Wang, Y. Wang, W. Yun, and W. Zhao. "Large Magnetoresistance in Diode Assisted ZnCoO Device." In 2018 IEEE International Magnetic Conference (INTERMAG). IEEE, 2018. http://dx.doi.org/10.1109/intmag.2018.8508123.

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Supriya, V., M. Sugiyama, S. Uthanna, and K. T. Ramakrishna Reddy. "Microstructure, magnetic and electrical properties of sprayed ZnCoO films." In SOLID STATE PHYSICS: Proceedings of the 56th DAE Solid State Physics Symposium 2011. AIP, 2012. http://dx.doi.org/10.1063/1.4710175.

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