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41.
Thanh Tran‐Phu Rahman Daiyan Zelio Fusco Zhipeng Ma Rose Amal Antonio Tricoli 《Advanced functional materials》2020,30(3)
3D Bi2O3 fractal nanostructures (f‐Bi2O3) are directly self‐assembled on carbon fiber papers (CFP) using a scalable hot‐aerosol synthesis strategy. This approach provides high versatility in modulating the physiochemical properties of the Bi2O3 catalyst by a tailorable control of its crystalline size, loading, electron density as well as providing exposed stacking of the nanomaterials on the porous CFP substrate. As a result, when tested for electrochemical CO2 reduction reactions (CO2RR), these f‐Bi2O3 electrodes demonstrate superior conversion of CO2 to formate (HCOO?) with low onset overpotential and a high mass‐specific formate partial current density of ?52.2 mA mg?1, which is ≈3 times higher than that of the drop‐casted control Bi2O3 catalyst (?15.5 mA mg?1), and a high Faradaic efficiency (FEHCOO?) of 87% at an applied potential of ?1.2 V versus reversible hydrogen electrode. The findings reveal that the high exposure of roughened β‐phase Bi2O3/Bi edges and the improved electron density of these fractal structures are key contributors in attainment of high CO2RR activity. 相似文献
42.
Amal Bouazizi Ghada Zaibi Amjad Iqbal Abdul Basir Mounir Samet Abdennaceur Kachouri 《国际射频与微波计算机辅助工程杂志》2019,29(8)
In this article, a novel 3D meandered planar inverted‐F antenna (PIFA) is proposed for dual band application targeting Wireless Body Area Network (WBAN). The proposed antenna is printed on the casing of a 3D‐base‐station model having a size of 88 × 95 × 10.2 mm3. The proposed PIFA covers two bands including medical implant communication service (MICS) (402‐405 MHz), as well as the industrial, scientific, and medical (ISM) (2.4‐2.48 GHz) bands. Each of the two bands can be controlled independently. The 3D configuration contains two linked meandered resonators to downsize the structure. Due to its conformal shape, omnidirectional radiation pattern, and low‐profile nature, the proposed PIFA is a potential candidate for targeting the WBAN applications. The proposed antenna, covering the MICS and ISM bands, works with an optimally matching (VSWR<2) at the aforementioned bands. The design concept was validated by fabricating the antenna prototype and measuring its characteristics. 相似文献
43.
M. Salem I. Massoudi Munirah A. Almessiere Amal L. Al-Otaibi Nada M. Alghamdi M. Gaidi M. A. El Khakani K. Khirouni 《Journal of Materials Science: Materials in Electronics》2017,28(21):15768-15774
Pulsed laser deposition of Al2O3 onto porous silicon (PS) is shown to provide excellent passivation of multi-crystalline silicon surfaces intended for solar cells applications. Surface passivation and reflectivity are investigated before and after the deposition of various nominal thicknesses of Al2O3 ranging from isolated nanoparticles to ~80 nm-thick films. The level of surface passivation is determined by techniques based on photoconductance and FTIR. As a result, the effective minority carrier lifetime increase from 1 to 130 μs at a minority carrier density (Δn) of 1?×?1013 cm?3. However, passivation scheme provide a significant decrease in the reflectivity; it’s reduced from 28% to about 5% after Al2O3/PS coating. 相似文献
44.
Hao Wu Hui Ling Tan Cui Ying Toe Jason Scott Lianzhou Wang Rose Amal Yun Hau Ng 《Advanced materials (Deerfield Beach, Fla.)》2020,32(18):1904717
Photocatalytic and photoelectrochemical processes are two key systems in harvesting sunlight for energy and environmental applications. As both systems are employing photoactive semiconductors as the major active component, strategies have been formulated to improve the properties of the semiconductors for better performances. However, requirements to yield excellent performances are different in these two distinctive systems. Although there are universal strategies applicable to improve the performance of photoactive semiconductors, similarities and differences exist when the semiconductors are to be used differently. Here, considerations on selected typical factors governing the performances in photocatalytic and photoelectrochemical systems, even though the same type of semiconductor is used, are provided. Understanding of the underlying mechanisms in relation to their photoactivities is of fundamental importance for rational design of high-performing photoactive materials, which may serve as a general guideline for the fabrication of good photocatalysts or photoelectrodes toward sustainable solar fuel generation. 相似文献
45.
Shenlong Zhao Xunyu Lu Lianzhou Wang Julian Gale Rose Amal 《Advanced materials (Deerfield Beach, Fla.)》2019,31(13)
The electrocatalytic nitrogen reduction reaction (NRR) is a promising catalytic system for N2 fixation in ambient conditions. Currently, metal‐based catalysts are the most widely studied catalysts for electrocatalytic NRR. Unfortunately, the low selectivity and poor resistance to acids and bases, and the low Faradaic efficiency, production rate, and stability of metal‐based catalysts for NRR make them uncompetitive for the synthesis of ammonia in comparison to the industrial Haber–Bosch process. Inspired by applications of carbon‐based metal‐free catalysts (CMFCs) for the oxygen reduction reaction (ORR) and CO2 reduction reaction (CO2RR), the studies of these CMFCs in electrocatalytic NRR have attracted great attention in the past year. However, due to the differences in electrocatalytic NRR, there are several critical issues that need to be addressed in order to achieve rational design of advanced carbon‐based metal‐free electrocatalysts to improve activity, selectivity, and stability for NRR. Herein, the recent developments in the field of carbon‐based metal‐free NRR catalysts are presented, along with critical issues, challenges, and perspectives concerning metal‐free catalysts for electrocatalytic reduction of nitrogen for synthesis of ammonia at ambient conditions. 相似文献
46.
Thanh Tran-Phu Manjunath Chatti Joshua Leverett Thi Kim Anh Nguyen Darcy Simondson Dijon A Hoogeveen Alexander Kiy The Duong Bernt Johannessen Jaydon Meilak Patrick Kluth Rose Amal Alexandr N. Simonov Rosalie K. Hocking Rahman Daiyan Antonio Tricoli 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(25):2208074
Unlocking the potential of the hydrogen economy is dependent on achieving green hydrogen (H2) production at competitive costs. Engineering highly active and durable catalysts for both oxygen and hydrogen evolution reactions (OER and HER) from earth-abundant elements is key to decreasing costs of electrolysis, a carbon-free route for H2 production. Here, a scalable strategy to prepare doped cobalt oxide (Co3O4) electrocatalysts with ultralow loading, disclosing the role of tungsten (W), molybdenum (Mo), and antimony (Sb) dopants in enhancing OER/HER activity in alkaline conditions, is reported. In situ Raman and X-ray absorption spectroscopies, and electrochemical measurements demonstrate that the dopants do not alter the reaction mechanisms but increase the bulk conductivity and density of redox active sites. As a result, the W-doped Co3O4 electrode requires ≈390 and ≈560 mV overpotentials to reach ±10 and ±100 mA cm−2 for OER and HER, respectively, over long-term electrolysis. Furthermore, optimal Mo-doping leads to the highest OER and HER activities of 8524 and 634 A g−1 at overpotentials of 0.67 and 0.45 V, respectively. These novel insights provide directions for the effective engineering of Co3O4 as a low-cost material for green hydrogen electrocatalysis at large scales. 相似文献
47.
Qingran Zhang Yinguang Chen Jian Pan Rahman Daiyan Emma C. Lovell Jimmy Yun Rose Amal Xunyu Lu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(40):2302338
Electrochemical synthesis of hydrogen peroxide (H2O2) through the selective oxygen reduction reaction (ORR) offers a promising alternative to the energy-intensive anthraquinone method, while its success relies largely on the development of efficient electrocatalyst. Currently, carbon-based materials (CMs) are the most widely studied electrocatalysts for electrosynthesis of H2O2 via ORR due to their low cost, earth abundance, and tunable catalytic properties. To achieve a high 2e− ORR selectivity, great progress is made in promoting the performance of carbon-based electrocatalysts and unveiling their underlying catalytic mechanisms. Here, a comprehensive review in the field is presented by summarizing the recent advances in CMs for H2O2 production, focusing on the design, fabrication, and mechanism investigations over the catalytic active moieties, where an enhancement effect of defect engineering or heteroatom doping on H2O2 selectivity is discussed thoroughly. Particularly, the influence of functional groups on CMs for a 2e−-pathway is highlighted. Further, for commercial perspectives, the significance of reactor design for decentralized H2O2 production is emphasized, bridging the gap between intrinsic catalytic properties and apparent productivity in electrochemical devices. Finally, major challenges and opportunities for the practical electrosynthesis of H2O2 and future research directions are proposed. 相似文献
48.
49.
Mariem Trad Wafa Miled Sofien Benltoufa Amal Boughattas Rihab Benslama Faten Fayala Amina Bakhrouf 《应用聚合物科学杂志》2018,135(34)
In this work, chitosan hydrogel has been synthesized and used to impart pH‐sensitivity and antimicrobial finish to cotton fabric. In order to enhance the incorporation rate of hydrogel, anionic, and cationic activation of the textile surface was applied and then compared. The antibacterial activity of the fabric was then studied. The results revealed an enhancement of the antibacterial activities of the modified fabrics against Escherichia coli, Listeria monocytogene, and Staphylococcus aureus bacteria's. The capacity of material to respond to pH change was studied and confirmed using contact angle method. The anionic fabric treated with hydrogel showed a better pH‐responsiveness. Scanning electron microscopic testing results has also confirmed that the deposition of hydrogel was clearly better with the anionic activation. The characteristics of breathability of the fabrics were analyzed. The results show that the moisture management behavior of the finished materials is significantly better than the control one. Although the permeability to air has reduced by 10%, the permeability to water vapor remained practically unchanged. Furthermore, the effects of the antibacterial finishing on the physical properties of the cotton fabrics were also investigated. It was established that the functionalized samples have changed structure parameters, thickness, air permeability, tensile strength, and resistance to wrinkles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46645. 相似文献
50.
Amal Al-Abri Yassine Jamoussi Naoufel Kraiem Zuhoor Al-Khanjari 《Telematics and Informatics》2017,34(6):878-893
There are a number of approaches to learning such as traditional approaches (teacher-centered) and collaborative approaches (learner-centered). Nowadays, the concepts of collaboration and social interactions are the major trends in education. Therefore, many researchers embrace these concepts to offer the educational field enhanced learning environments which are supported by communication and collaboration techniques. The adaptation causes the existence of varied approaches which are addressing the collaborative learning techniques. As a result, there is a need for a mechanism to study those approaches and highlight their eminence. The aim of this paper is to give a comprehensive overview about the state-of-art in collaborative learning, especially by integrating social media tools. To do so, the study adopts a classification framework based on four different views (subject, purpose, method, and tool). The framework has been used to compare ten collaborative e-learning approaches. The finding indicates the potential of all approaches in developing an online learning environment for remote collaborative learning despite the lack of fulfilling all the requirements highlighted in the four views. 相似文献