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31.
Hang Shi Qiuyang Yu Guoliang Liu Xiaohong Hu 《International Journal of Hydrogen Energy》2021,46(33):17097-17105
Transition metal phosphides (TMPs) have been considered as cheap alternatives of precious metal platinum for electrochemical hydrogen evolution reaction (HER). In the past decades, many reports have indicated that the engineering of heterointerfaces between different components could efficiently enhance the activity of HER catalysts. Here, we report a facile method to construct Ni12P5–Ni2P heterostructure by using a low temperature phosphorization strategy. The obtained Ni12P5–Ni2P heterostructure shows high activity toward HER with an overpotential value of 166 mV at 10 mA cm?2 and a Tafel slope of 60 mV dec?1 in 0.5 M H2SO4. Compared with pure Ni2P and Ni12P5, the Ni12P5–Ni2P heterostructure has more active sites and faster HER kinetics due to the presence of the interfaces between Ni12P5 and Ni2P. Furthermore, we used the obtained Ni12P5–Ni2P as cathodic catalyst and IrO2/Ti as anodic material to set up a proton exchange membrane (PEM) electrolyzer which shows good stability after 120 h continuous constant current electrolysis at 200 mA cm?2. This work demonstrates the positive effect of heterostructure for HER catalysts and provides a feasible strategy for constructing earth-abundant electrocatalysts. 相似文献
32.
《Ceramics International》2022,48(3):3536-3543
We investigated the optical and electrical properties of Ta2O5/Ag/Ta2O5 films as functions of the thicknesses of the Ta2O5 and Ag layers. It was found that with an increase in the thicknesses of the Ta2O5 and Ag layers from 10 to 40 nm and from 12 to 24 nm, respectively, the sheet resistance, carrier concentration, electron mobility, and resistivity of the Ta2O5/Ag/Ta2O5 film varied from 2.02 to 8.95 Ω/sq, 5.74 × 1021 to 2.92 × 1022 cm–3, from 13.21 to 24.07 cm2/V·s, and from 8.89 × 10-6 to 8.24 × 10-5 Ω cm, respectively. The average transmittance (Tav) of the multilayer samples ranged from 57.18% to 93.99%, and it depended on the Ta2O5 and Ag layer thicknesses. The highest Tav of 93.99% was observed for the film with 35 nm thick Ta2O5 and 18 nm thick Ag layers, and the peak Haacke's figure of merit (157.04 × 10–3 Ω–1) was obtained for 20 nm thick Ta2O5 and 21 nm thick Ag layers. Ta2O5 (100 nm) and Ta2O5/Ag/Ta2O5 (20 nm/21 nm/20 nm) samples had optical bandgaps of 4.70 and 4.45 eV, respectively. Film Wizard simulations were conducted to understand the dependence of the transmittance of the multilayer on the thicknesses of the Ta2O5 and Ag layers, and phasor analyses were performed to determine how the transmittance of the Ta2O5/Ag/Ta2O5 (20 nm/21 nm/20 nm) film depended on the Ta2O5 layer's thickness. 相似文献
33.
《Ceramics International》2022,48(4):5040-5053
Using tailings as material to prepare glass-ceramic is an excellent way to achieve the resource utilization of solid waste. However, at present, researches on the solidification and migration of heavy metals are limited. Therefore, in this study, ten groups of samples were prepared by controlling sintering temperatures. The solidification, migration, and leaching behavior of non-volatile and volatile heavy metals were studied. The research showed that, with the increase of temperature, the properties of the samples were improved. Fe participated in the phase transformation and evolved into insoluble iron pyroxenes solid solution, while Pb was homogeneously distributed in the glass matrix of glass-ceramics. The leaching concentrations of Fe and Pb in the glass-ceramics were 0.055 mg/L ~0.087 mg/L and 0.074 mg/L ~0.140 mg/L, which were far below the threshold value. The results showed that heavy metals can be effectively solidified in glass-ceramics and have good environmental benefits. 相似文献
34.
《Ceramics International》2022,48(7):9400-9406
In the present study, we prepared vacancy-engineered V2O5-x films for electrochromic (EC) applications. To investigate the vacancy effect of V2O5-x films with high EC performance capabilities, precursor concentrations of V-based sol solutions were varied at 1 wt%, 5 wt%, and 10 wt%. Among them, V2O5-x films with a precursor concentration of 5 wt% (V2O5-5wt%) showed superior EC performance outcomes due to the (001)-plane-oriented crystal structure, which provides high electrical conductivity with the oxygen vacancy (Vo). In addition, the gravel-like uniform surface morphology with the optimized film thickness provides a stable electrochemical reaction during the EC measurement. As a result, V2O5-5wt% exhibited fast switching speeds (2.1 s for coloration and 3.6 s for bleaching), high transmittance modulation (ΔT) (51.32%), high coloration efficiency (CE) (52.3 cm2/C), and excellent cycle stability (85.85% ΔT retention after 500 cycles). In addition, V2O5-5wt% showed energy storage capability of 443.7 F/g at a current density of 2 A/g, thus proving its potential for use in multi-functional applications. Therefore, these results provide valuable insight related to the engineering of vacancies in EC films to achieve high-performance EC devices and additional multi-functional applications. 相似文献
35.
Wonjun Choi Sungjae Hong Yeonsu Jeong Yongjae Cho Hyung Gon Shin Ji Hoon Park Yeonjin Yi Seongil Im 《Advanced functional materials》2021,31(9):2009436
Among many of 2D semiconductor-based devices, type III PN junction diodes are given special attentions due to their unique function, negative differential resistance (NDR). However, it has been found uneasy to achieve well-matched type III PN junctions from 2D–2D van der Waals heterojunctions. Here, the authors present other alternatives of type III heterojunctions, using 2D p-MoTe2/organic n-type dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) and 2D p-WSe2/n-MoOx systems. Those junction diodes appear to well-demonstrate static and dynamic NDR behavior via resonant tunneling and electron–hole recombination. Extended to an inverter circuit, p-MoTe2/n-HAT-CN diode enables multilevel inverter characteristics as monolithically integrated with p-MoTe2 channel field effect transistor. The same NDR diode shows dynamic LC oscillation behavior under a constant DC voltage, connected to an external inductor. From p-WSe2/n-MoOx oxide diode, similar NDR behavior to those of p-MoTe2/n-HAT-CN is again observed along with LC oscillations. The authors attribute these visible oscillation results to high peak-to-valley current ratios of their organic or oxide/2D heterojunction diodes. 相似文献
36.
《Ceramics International》2022,48(2):1451-1483
Metal/ceramic composites are in high demand in several industries because of their superior thermo-mechanical properties. Among various composite types, the interpenetrating phase composites (IPCs) with percolating metallic and ceramic phases offer manifold benefits, such as a good combination of strength, toughness, and stiffness, very good thermal properties, excellent wear resistance, as well as the flexibility of microstructure and processing route selection, etc. The fabrication of metal/ceramic IPCs typically involves two steps - i) processing of an open porous ceramic body, and ii) infiltration of metallic melt in the pores to fabricate the IPC. Although significant progress has been made in recent years for developing both porous ceramics and melt infiltration methods, to the best of the knowledge of the authors, no review article summarizing all the aspects of processing and properties of IPCs has been published till date. This review article is aimed at filling this gap. Starting with a brief introduction about the current status and applications of IPCs, the various processing routes for fabricating open porous ceramic preforms and melt infiltration techniques have been discussed. Subsequently, the data available for various important physical, mechanical, and thermal properties for IPCs have been critically analyzed to thoroughly understand their dependence on various structural and processing parameters. To compare the properties of IPCs with other relevant materials, seven different Ashby material property maps have been used, and the domains for IPCs have been created in them. For each map, the concept of material indices has been employed to critically discuss how IPCs perform in relation to other material classes for various optimum design conditions. Finally, a detailed future outlook for further research on IPCs has been provided. 相似文献
37.
《Ceramics International》2022,48(18):26508-26518
Flexible photoelectronic devices are in demand right now. In this work, a new family of biopolymer-based photodetectors is described. Chitosan (CS) was utilized as a safe, biodegradable host biopolymer, and nanostructured barium tungstate (BaWO4) particles were used as the nanofiller of the biopolymer matrix to prepare flexible optical sensors. The co-precipitation process was used to produce the filler powders, which were then dried at room temperature without using any surfactants or hazardous solvents. The fabricated sensor showed high flexibility and sensitivity to UV/proton/alpha and laser irradiation. X-ray diffraction (XRD), XPS, FTIR, EDX-map analysis also confirmed the successful synthesis, related chemical binding, and elements in the nanocomposite structure. According to the TEM images, the average particle size of synthesized BaWO4 NPs was obtained at about 110 nm. A considerable luminescence emission was observed in the constructed sensor's blue/green and ultraviolet spectral regions under various excitation sources. The developed sensor was nontoxic to the cells and provided soft, thin, antibacterial activity, flexible, and comfortable contact with skin, and promising ionizing ray detection applications in flexible optical sensors. 相似文献
38.
Upconversion phosphors are known as a material system that can convert near-infrared light into visible/ultraviolet emissions by sequentially absorbing multiple photons. The studies on upconversion materials often use two rare earth (RE) ions as a sensitizer-activator pair. We investigated the influences on luminescence intensity depending on Cr-doping content (x) of hexagonal NaLu0.98–xCrxF4Er0.02 (x = 0–0.9) upconversion material by substituting Lu3+ ions with Cr3+in the absence of Gd3+. The change in upconversion luminescence intensity appears with saddle-like shape. We suggest that Cr3+ ions play the dual role as a constituent in host lattice and a sensitizer in the upconversion process. Optimal conditions for gaining the strongest upconversion emission correspond to x = 0.3–0.5, where there are effective energy transfers between Cr3+ and Er3+ ions and CrEr dimers. Apart from these values, the emission intensity decreases rapidly which can be ascribed to the absence of multiple-photon absorption for the case of low Cr3+ contents, and to the coupling between Cr3+ and/or Er3+ ions for the case of high Cr3+ contents. Magnetization and electron-spin-resonant measurements were performed to understand the correlation between the optical and magnetic properties. 相似文献
39.
以2219铝合金为基板,研究了不同脉冲激光-电弧布置方式下的熔滴过渡与焊缝形貌特征,分析了熔深增加的机理. 结果表明,当脉冲激光照射母材时,脉冲激光主要提供对母材的热输入,母材温度的增加有助于促进熔滴铺展,稳定熔滴过渡过程;当脉冲激光照射熔滴缩颈时,主要提供对熔滴的力输入,蒸发反力的作用下形成"一脉一滴",显著提高熔滴过渡频率与熔滴飞行速度,增加了熔滴对熔池的冲击力,熔深增加;当脉冲激光交替的照射熔池和熔滴时,一方面能够对母材进行加热,有助于熔滴的铺展,另一方面能够提高熔滴过渡频率,提高焊缝的均匀性. 相似文献
40.
The complexity and uncertainties associated with mining operations often lead to deviations from short-term plans. A proactive approach will predict such deviations and help minimise opportunity losses, providing economic and operational gains. This paper presents an optimisation tool as a dynamic shovel allocation decision-maker for mining operation simulation models. The objectives of the optimisation tool are to provide shovel allocations to mining faces in order to maximise production, meet desired head grade and tonnage at the crushers, and minimise shovel movements. This paper presents the development and implementation of the optimisation tool with an iron ore mine case study. 相似文献