Simultaneously improving the electrical properties and long-term stability of ZnO varistor ceramics by reversely manipulating intrinsic point defects

Men, Guo; Zhao, Xia; Shi, Weidong; Zhang, Boyu; Wu, Kangning; Li, Jianying

doi:10.1016/j.jeurceramsoc.2021.09.062

Cited by 35 publications

(12 citation statements)

References 43 publications

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“…According to the abovementioned and illustrated results, the use of pure ZnO as pure or modified with 1–10% K 2 O calcined at 400°C for 3 h in oxygen, the following remarks can be summarized as follows: Because of its high activity, ZnO is a multitalented, flattering oxide in many processes 1–24 . ZnO as pure and modified catalysts were easily prepared herein and characterized by their nanoscale crystallite size in, that is, 22.9–28.0 nm, high basicity (ca.…”

Section: Conclusive Remarksmentioning

confidence: 99%

“…Because of its high activity, ZnO is a multitalented, flattering oxide in many processes 1–24 . ZnO as pure and modified catalysts were easily prepared herein and characterized by their nanoscale crystallite size in, that is, 22.9–28.0 nm, high basicity (ca.…”

Section: Conclusive Remarksmentioning

confidence: 99%

“…Much attention has been focused on its technological applications in solar cells, [14][15][16] piezoelectric nanogenerators and force sensors, 17 and varistor ceramics. 18 Due to the wide range of technological applications of ZnO, recently, various preparation techniques have been developed. [19][20][21][22][23][24] Few years ago, we investigated the catalytic properties of various ZnO samples prepared from different precursors, 25 namely Zn(CH 3 CO 2 ) 2 •2H 2 O, Zn 3 (C 6 H 5 O 7 ) 2 •2H 2 O and Zn(NO 3 ) 2 •6H 2 O, during the decomposition of ethanol.…”

Section: Introductionmentioning

confidence: 99%

“…ZnO is considered a nontoxic material owing to its relatively fast electron mobility, high conductivity, photo‐corrosion resistance, and low availability. Much attention has been focused on its technological applications in solar cells, 14–16 piezoelectric nanogenerators and force sensors, 17 and varistor ceramics 18 . Due to the wide range of technological applications of ZnO, recently, various preparation techniques have been developed 19–24 .…”

Section: Introductionmentioning

confidence: 99%

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Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Halawy

Osman

Rooney

2022

Energy Science & Engineering

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Herein we demonstrate the preparation and characterization of nanocrystalline ZnO, either pure or promoted with 1–10 wt.% K2O. All catalysts calcined at 400°C were in the nano‐crystallite scale as confirmed by X‐ray powder diffraction analysis in the 22.9–28.0 nm range. According to the CO2‐temperature‐programmed desorption study using thermogravimetric analysis and differential scanning calorimetry techniques, they have a broad spectrum of surface basic sites. Because of the significance of methyl ethyl ketone (MEK) as a next‐generation biofuel candidate with high‐octane, low boiling point, and relatively high vapor pressure. The prepared catalysts were examined during the direct production of MEK via 2‐butanol (2B) dehydrogenation. Among catalysts tested, ZnO promoted with 1% K2O showed a superior catalytic activity towards the conversion of 2B to MEK, that is, 71.7% at a reaction temperature of 275°C. The selectivity for the production of MEK over all catalysts was ≥95% across all catalysts when using N2‐gas as a carrier. The use of airflow in this reaction resulted in a clear loss of selectivity toward MEK production as well as the appearance of undesirable products such as acetone and methanol. All catalytic properties of catalysts, particularly those of moderate strength, were highly correlated with the distribution of surface basic sites. Finally, a reaction mechanism was proposed for the dehydrogenation of 2B, followed by the partial oxidation of MEK.

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Section: Conclusive Remarksmentioning

confidence: 99%

Section: Conclusive Remarksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Halawy

Osman

Rooney

2022

Energy Science & Engineering

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“…Electronic ceramics with variable resistance on voltages are of importance in protecting electrical and electronic devices from overvoltage [ 1 , 2 , 3 , 4 , 5 ]. Among various kinds of varistor ceramics, ZnO based varistor ceramics are the most widely employed ones, due to their extremely high nonlinear coefficient and excellent energy absorption capability [ 6 , 7 ]. It has been acknowledged that the unique nonlinear current-voltage characteristics of ZnO based varistor ceramics originate from the double Schottky barriers (DSBs) at grain boundaries (GBs) [ 5 , 8 ], which further root in the underlying defect structures including the negatively charged interface sates and the positively charged intrinsic point defects in depletion layers [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Xie¹,

Wang

2022

Materials

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In this paper, evolution of microstructures, electrical properties and defects of the double Schottky barrier during the sintering process were investigated by quenching ZnO varistor ceramics at different sintering stages. It was found that morphology of the samples changed little when the temperature was below 800 °C. Remarkable enhancement of the Schottky barrier height and electrical properties took place in the temperature range between 600 °C and 800 °C. The Bi-rich intergranular layer changed from β phase to α phase. The interfacial relaxation at depletion/intergranular layers became detectable in the samples. Meanwhile, a distinct relaxation loss peak from electron trapping of interface states was observed instead of two dispersed ones. It indicated that the differences among the Schottky barriers in ZnO varistor ceramics became smaller with the process of sintering, which was also supported by the admittance spectra. In addition, oxygen vacancy was found more sensitive to the sintering process than zinc interstitial. The results could provide guidance for fine manipulating the Schottky barrier and its underlying defect structures by optimizing sintering process.

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Effects of B₂O₃ Dopants on the Electrical Properties of Ta‐Doped SnO₂ Varistors

Yang,

Zhao,

et al. 2024

Adv Eng Mater

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As a new core component of surge arresters, it is crucial for manganese dioxide varistors to solve the challenges of reducing the leakage current and lowering the residual voltage ratio. In this study, the electrical characteristics of tin dioxide varistors using B2O3 as the acceptor dopant and Ta2O5 as the donor dopant are investigated. Several tin dioxide based varistors doped with different amounts of B2O3 are prepared and characterized by the researchers. X ray diffraction (XRD) is used to analyze the structural features of the samples and to observe the phases involved. It is found that the B2O3 dopant provides oxygen vacancies, reduces the grain size, increases the barrier height, and decreases the residual pressure ratio. The Ta2O5 dopant provides donor defects and free electrons needed to form the barrier. When balancing the concentrations of B2O3 and Ta2O5, the optimum dopant concentrations is found to be 0.1 mol% of B and 0.05 mol% of Ta; these concentrations result in a leakage current of 0.25 μA cm−2, a residual pressure ratio of 1.95, a nonlinear coefficient of 25, and a voltage gradient of 394 V mm−1 for the varistor.

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Simultaneously improving the electrical properties and long-term stability of ZnO varistor ceramics by reversely manipulating intrinsic point defects

Cited by 35 publications

References 43 publications

Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Effects of B₂O₃ Dopants on the Electrical Properties of Ta‐Doped SnO₂ Varistors

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Simultaneously improving the electrical properties and long-term stability of ZnO varistor ceramics by reversely manipulating intrinsic point defects

Cited by 35 publications

References 43 publications

Highly basic and active ZnO–x% K2O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Highly basic and active ZnO–x% K2O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Effects of B2O3 Dopants on the Electrical Properties of Ta‐Doped SnO2 Varistors

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Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Highly basic and active ZnO–x% K₂O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

Effects of B₂O₃ Dopants on the Electrical Properties of Ta‐Doped SnO₂ Varistors