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11.
《Ceramics International》2021,47(20):28976-28984
In the era of Photonics, design and development of novel rare earth ion-doped quantum dots (QDs) for optoelectronic applications has gained significant interest owing to their outstanding characteristics. Simultaneously, the creation of a new class of photocatalytic materials on the nanoscale is also imperative for environmental purification. Thus, we report on wet chemical synthesis, the structural, morphological, and optical characteristics, fluorescence, and hydrogen evolution of ZnS:Eu (0, 2, 4, and 6 at%) QDs for optoelectronic and photocatalytic applications. Comprehensive structural studies depicted that Eu3+ ions were efficiently substituted into the host matrix and altered the original structure of the ZnS compound. The emission spectra of the ZnS:Eu QDs exhibited distinctive red fluorescence owing to the transition of dopant ions in 5D0 - 7F1, 5D0 - 7F2, 5D0 - 7F3, and 5D0 - 7F4 energy levels of the 4f orbital of the Eu3+ ions. Moreover, the photocatalytic properties of ZnS:Eu (6 at%) QDs possess better catalytic efficiency toward hydrogen evolution through a water splitting mechanism under simulated sunlight irradiation. The observed photocatalytic phenomenon in the synthesized samples agreed well with the luminescence properties exhibited by the QDs. 相似文献
12.
Sakib Ferdous Jared L. Dopp Nigel F. Reuel 《American Institute of Chemical Engineers》2021,67(10):e17389
Optimal tip sonication settings, namely tip position, input power, and pulse durations, are necessary for temperature sensitive procedures like preparation of viable cell extract. In this paper, the optimum tip immersion depth (20–30% height below the liquid surface) is estimated which ensures maximum mixing thereby enhancing thermal dissipation of local cavitation hotspots. A finite element (FE) heat transfer model is presented, validated experimentally with (R2 > 97%) and used to observe the effect of temperature rise on cell extract performance of Escherichia coli BL21 DE3 star strain and estimate the temperature threshold. Relative yields in the top 10% are observed for solution temperatures maintained below 32°C; this reduces below 50% relative yield at temperatures above 47°C. A generalized workflow for direct simulation using the CONSOL code as well as master plots for estimation of sonication parameters (power input and pulse settings) is also presented. 相似文献
13.
Kirti M. Yenkie Jean Pimentel Ákos Orosz Heriberto Cabezas Ferenc Friedler 《American Institute of Chemical Engineers》2021,67(7):e17253
Wastewater treatment consists of three or four sequential stages: preliminary, primary, secondary, and tertiary. Each stage can comprise multiple alternative technologies that can perform the same tasks with different efficiencies, operating times, and costs. Thus, we propose a systematic approach for designing wastewater treatment networks by utilizing principles of mathematical modeling and generating an exhaustive enumeration of all the possible technologies and their connections during the early stages of designing a treatment facility. Some of these structures are nonintuitive and include recycling, reprocessing, bypasses, and multiple technologies in parallel or series to remove the same contaminant. The nonintuitive structures with multiple technologies may provide a measure of resilience compared to typical heuristic designs. Thus, the combination of P-graph methodology and the sequence of treatment technologies predicted via the optimization algorithm from the maximal structure is based on holistic considerations and does not lead to suboptimal solutions. 相似文献
14.
Mit Rita Goswami Prayas Singh Pankaj Chamoli Sumit Bhardwaj Kuldeep Kumar Raina Ravi Kumar Shukla 《应用聚合物科学杂志》2021,138(43):51260
ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s−1. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10−3% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications. 相似文献
15.
《International Journal of Hydrogen Energy》2022,47(38):16933-16948
Higher alcohols synthesis (HAS) from syngas (CO/H2) has attracted widespread attention, while the low selectivity and poor stability of the catalysts mainly stumbled its industrial application. In the work, Ni–Co alloy nanoparticles (NPs) derived from Co1-xNixAl2O4 loaded on the SiO2 with large specific surface area were prepared; and during reaction, the highly dispersed Ni–Co alloys were self-optimized to Ni–Co alloy@Co–Co2C. Importantly, Ni–Co alloy@Co–Co2C can be regenerated through oxidation - reduction - self-optimization process. Characteristic results indicated that the structural liberalization during the reaction process inhibited the loss of Ni, regulated and balanced the dual active sites of the catalyst and the Ni–Co alloys were regenerated after the re-oxidation and re-reduction process. The optimized catalyst exhibited excellent catalytic performance, including a high total selectivity to alcohols of 39.3% and an excellent catalytic stability at 250 °C, 3.5 MPa (H2/CO = 2) and a space velocity of 6000 mL (gcat h)?1. In addition, the Ni–Co alloy@Co–Co2C catalyst after stability test could recover its original catalytic performance after re-oxidation and re-reduction. The renewable characteristics and superior catalytic performance of Ni–Co alloy@Co–Co2C made the catalyst to be one of the potential industrial catalysts for HAS. 相似文献
16.
《Ceramics International》2022,48(3):3368-3373
Over the recent past, lead-based halide perovskite materials have drawn significant attention due to their excellent optical and electrical properties for solar cells and optoelectronics applications. However, the toxicity of lead elements and instability under ambient conditions leads to develop alternative compositions. Herein, we report a novel mechanochemical synthesis of tin iodide-based double perovskites (A2SnI6; A = Rb+, Cs+, methylammonium, and formamidinium), and their structural, optical, and electrical properties are investigated. Importantly, we found that the hydrogen iodide (HI) addition during the ball-milling process minimizes secondary phase formation in the synthesized A2SnI6 powders. The effects of HI addition and the A-site substitution are investigated with respect to the lattice parameters, optical bandgaps, and electrical properties of the synthesized perovskite materials. Our results demonstrate essential information to improve the understanding of halide perovskite materials and develop efficient lead-free perovskite photoelectric devices. 相似文献
17.
《International Journal of Hydrogen Energy》2022,47(7):4559-4567
Synthesis of mixed alcohols together with clean fuels from syngas via Fischer-Tropsch synthesis is an attractive route for the utilization of coal, natural gas and biomass. In this work, a monometallic cobalt catalyst (Co/SiO2-EOAM) was synthesized by impregnation using ethanolamine modified silica pellet as support and employed for the conversion of syngas. The combustion of carbon and nitrogen species during the calcination of catalyst facilitated the interaction between cobalt and support, which promoted the cobalt dispersion while inhibited the reduction of cobalt oxide. The Co/SiO2-EOAM catalyst exhibited much higher activity and selectivity to alcohols compared to un-modified silica supported cobalt catalyst (Co/SiO2). The higher activity was resulted from the improved cobalt dispersion. The co-existence of abundant metallic cobalt and Co2+ species were responsible for the increasing of alcohols selectivity. 相似文献
18.
《Ceramics International》2022,48(11):15243-15251
Green combustion was used to prepare a ferrite composition of Mg0.4Zn0.6Fe2O4 using a blend of fresh lemon juice as a natural fuel-reductant. Effect of heat treatment on phase, morphological, dielectric, and humidity sensor properties is discussed. The formation of a cubic spinel ferrite has been established by XRD-diffraction and vibrational spectroscopic studies. The experimental lattice parameter ranges from 8.3721 to 8.3631 Å. The broadening of octahedral band (υ2) in the vibrational spectra is an identification for the existence of ferrite nanoparticles in various sizes. The typical crystallite size ranges from 10.2 to 36.9 nm. Using micrographs obtained from field-effect scanning electron microscopy (FESEM), researchers observed a spherical-shaped microstructure with agglomerated nanoparticles. Dielectric investigations have shown that the current ferrite composition has typical dielectric dispersion. The highest reported value for saturation magnetization (Ms) in the present study is 33 emu/g. Magnetic behaviour is primarily influenced by magnetocrystalline anisotropy, cation distribution, and crystallite size. The existence of void spaces in the sintered samples, as well as their porous nature, rendered them suitable for humidity sensor applications. Sintered samples have good sensing capability at 900 °C. The current findings are integrated in terms of cation distribution and magnetocrystalline anisotropy, assuming fine size effects of ferrite nanoparticles. 相似文献
19.
《International Journal of Hydrogen Energy》2022,47(4):2234-2244
In this work, the solution plasma-assisted method was used to prepare NiMnAl-LDO (layered double oxides) catalysts with different treatment times, which were used for the CO2 methanation reaction. Solution plasma treatment can enhance the dispersibility of the catalyst, create oxygen defects and improve the chemical adsorption capacity of the catalyst. The results show that the low-temperature activity of the catalyst has been improved after the solution plasma treatment. We demonstrate that the NiMnAl-LDO-P(20) catalyst with high dispersion has the highest catalytic activity in CO2 methanation (81.3% CO2 conversion and 96.7% CH4 selectivity at 200 °C). Even though working for 70 h, the catalyst is still highly stable. This work provides a great promise for improving the low-temperature activity of Ni-based catalysts. 相似文献
20.
《International Journal of Hydrogen Energy》2022,47(71):30722-30731
To improve the fuel economy, it is crucial to promote the low-temperature performance in eliminating diesel emissions. The work investigates the impact of different MnO2/Mn2O3 phase ratio on the low-temperature performance of Pt-based monolithic diesel oxidation catalyst. Near equal ratio of MnOx phase could form the three-phase (platinum, MnO2, Mn2O3) interfacial structure, leading to the smaller platinum particle size and exhibiting the higher interface rate (1.6–11.1 times) than other mono-manganese oxide with platinum. Besides, the higher oxygen mobility and more active oxygen species could be contributed to the positive effect of Pt/MnOx interface, which are prevalent to activate the reactant and greatly enhance the TOF value (1.4–20.8 times). The results imply that the modification of multi-phase metal/oxide interface is potential in dispersing platinum for greatly enhancing the catalytic efficiency. 相似文献