Nitrogen heterocycles belong to a highly important class of compounds which are found in various natural products, biologically active structures, and medicinally relevant compounds. Therefore, there ...is continuing interest in the development of novel synthetic methods for the construction of nitrogen containing heterocycles. Recently, radical insertion reactions into isonitriles have emerged as an efficient and powerful strategy for the construction of nitrogen heterocycles, such as phenanthridines, indoles, quinolines, quinoxalines, and isoquinolines. This review highlights recent advances in this fast growing research area and also includes important pioneering studies in this area.
Na‐ion batteries (NIBs) are ideal candidates for solving the problem of large‐scale energy storage, due to the worldwide sodium resource, but the efforts in exploring and synthesizing low‐cost and ...eco‐friendly anode materials with convenient technologies and low‐cost raw materials are still insufficient. Herein, with the assistance of a simple calcination method and common raw materials, the environmentally friendly and nontoxic N‐doped C@Zn3B2O6 composite is directly synthesized and proved to be a potential anode material for NIBs. The composite demonstrates a high reversible charge capacity of 446.2 mAh g−1 and a safe and suitable average voltage of 0.69 V, together with application potential in full cells (discharge capacity of 98.4 mAh g−1 and long cycle performance of 300 cycles at 1000 mA g−1). In addition, the sodium‐ion storage mechanism of N‐doped C@Zn3B2O6 is subsequently studied through air‐insulated ex situ characterizations of X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and Fourier‐transform infrared (FT‐IR) spectroscopy, and is found to be rather different from previous reports on borate anode materials for NIBs and lithium‐ion batteries. The reaction mechanism is deduced and proposed as: Zn3B2O6 + 6Na+ + 6e− ⇋ 3Zn + B2O3 ∙ 3Na2O, which indicates that the generated boracic phase is electrochemically active and participates in the later discharge/charge progress.
N‐doped C@Zn3B2O6 (NC@ZBO) composite is chemically synthesized in a green manner through a simple method, and shows considerable sodium‐ion storage ability, including high reversible charge capacity (446.2 mAh g−1) and suitable average voltage (0.69 V), together with application potential in full cells (300 cycles). The sodium‐ion storage mechanism of Zn3B2O6 is also found rather different from relevant experiments on borates and deduced to be Zn3B2O6 + 6Na+ + 6e− ⇋ 3Zn + B2O3 · 3Na2O.
Nitrogen‐doped carbon (NC) materials have been proposed as next‐generation oxygen reduction reaction (ORR) catalysts to significantly improve scalability and reduce costs, but these alternatives ...usually exhibit low activity and/or gradual deactivation during use. Here, we develop new 2D sandwich‐like zeolitic imidazolate framework (ZIF) derived graphene‐based nitrogen‐doped porous carbon sheets (GNPCSs) obtained by in situ growing ZIF on graphene oxide (GO). Compared to commercial Pt/C catalyst, the GNPCSs show comparable onset potential, higher current density, and especially an excellent tolerance to methanol and superior durability in the ORR. Those properties might be attributed to a synergistic effect between NC and graphene with regard to structure and composition. Furthermore, higher open‐circuit voltage and power density are obtained in direct methanol fuel cells.
Nitrogen‐doped: A new oxygen reduction reaction electrocatalyst was obtained from ZIF‐derived porous carbon and graphene. The catalyst exhibits high activity, superior tolerance to methanol, and good stability in comparison to commercial Pt/C catalyst.
With the recent adoption of Positive Psychology in foreign language education, academic motivation and resilience as secondary components of positive psychology have started to receive academic ...attention. Undoubtedly, students require constant motivation because learning a foreign language is a long-term effort especially in the first stage that they usually lose their interest and motivation. When students are academically motivated, they can put high effort to learn the language. This study aims to inspect the relationship between Chinese EFL learners' resilience and academic motivation. To this end, 482 students from different colleges and universities in China were selected and they completed the resilience and academic motivation questionnaires. Spearman's rho index and multiple regressions were run for data analyses. Results of the study indicated that there is a positive and significant association showing a relationship between these two constructs. Moreover, two components of motivation, namely interjected regulation and external regulation by attendance proved to be the best predictors of learners' resilience. The paper concludes with some pedagogical implications; for instance, motivation can be considered as a primary point for the progress of resilience for the next steps of language success.
Since turnover intention has a negative impact on teachers’ productivity, a bulk of educational research has studied the personal, organizational, and emotional predictors of this construct. ...Nevertheless, the predictive function of burnout and job-related stress as two emotional factors has been less attended to by scholars. To address this gap, the current empirical study explored the role of burnout and job-related stress in Chinese English teachers’ turnover intention during distance education. In doing so, three pre-designed questionnaires were distributed among 221 Chinese teachers. Having collected the needed data, the researcher analyzed the datasets through the Pearson correlation test and multiple regression analysis. As a result of the correlation test, positive, direct relationships were found between burnout, job-related stress, and teacher turnover intention. Moreover, the results of the regression analysis evinced the significant role of burnout and job-related stress in predicting Chinese English teachers’ turnover intention. The implications of the results are thoroughly discussed.
Li‐O2 batteries with ultrahigh theoretical energy densities usually suffer from low practical discharge capacities and inferior cycling stability owing to the cathode passivation caused by insulating ...discharge products and by‐products. Here, a trifunctional ether‐based redox mediator, 2,5‐di‐tert‐butyl‐1,4‐dimethoxybenzene (DBDMB), is introduced into the electrolyte to capture reactive O2− and alleviate the rigorous oxidative environment of Li‐O2 batteries. Thanks to the strong solvation effect of DBDMB towards Li+ and O2−, it not only reduces the formation of by‐products (a high Li2O2 yield of 96.6 %), but also promotes the solution growth of large‐sized Li2O2 particles, avoiding the passivation of cathode as well as enabling a large discharge capacity. Moreover, DBDMB makes the oxidization of Li2O2 and the decomposition of main by‐products (Li2CO3 and LiOH) proceed in a highly effective manner, prolonging the stability of Li‐O2 batteries (243 cycles at 1000 mAh g−1 and 1000 mA g−1).
A trifunctional ether‐based redox mediator, DBDMB, is introduced into the electrolyte to capture reactive discharge intermediates (O2−) with reduced formation of by‐products, regulate solution growth of Li2O2, and co‐oxidize Li2O2 and by‐products (Li2CO3 and LiOH). Li‐O2 batteries with large capacity and long cycling stability have been achieved.
Hollow ceramic microspheres (HCMs) have widespread applications in aerospace and electronic areas owing to their multiple merits such as low density, low thermal conductivity, oxidation, and ...high‐temperature resistance. In this work, monodispersed HCMs were fabricated based on preceramic polymers and the pulse‐controlled coaxial injection approach. The size and shell morphology of hollow ceramic spheres can be flexibly tailored by adjusting the diameters of coaxial needles, and the composition and flow rates of inner and outer liquids. As‐obtained HCMs were comprised of ultrafine nanocrystals of ZrO2, SiO2, ZrC, and SiC, which can enhance the interfacial polarization effect. Through optimization of microstructure and composition, the electromagnetic shielding performance of HCMs reached up to 45 dB in the frequency range of 12–18 GHz. This work demonstrates a facile and general method for the fabrication of monodispersed HCMs.
This work demonstrates a facile and general method for the fabrication of monodispersed hollow ceramic microspheres with precise control of size and shell thickness and their potential applications for electromagnetic shielding materials.
The limited triple‐phase boundaries (TPBs) in solid‐state cathodes (SSCs) and high resistance imposed by solid electrolytes (SEs) make the achievement of high‐performance all‐solid‐state ...lithium‐oxygen (ASS Li‐O2) batteries a challenge. Herein, an adjustable‐porosity plastic crystal electrolyte (PCE) has been fabricated by employing a thermally induced phase separation (TIPS) technique to overcome the above tricky issues. The SSC produced through the in‐situ introduction of the porous PCE on the surface of the active material, facilitates the simultaneous transfer of Li+/e−, as well as ensures fast flow of O2, forming continuous and abundant TPBs. The high Li+ conductivity, softness, and adhesion of the dense PCE significantly reduce the battery resistance to 115 Ω. As a result, the ASS Li‐O2 battery based on this adjustable‐porosity PCE exhibits superior performances with high specific capacity (5963 mAh g−1), good rate capability, and stable cycling life up to 130 cycles at 32 °C. This novel design and exciting results could open a new avenue for ASS Li‐O2 batteries.
Holey cathodes, Battman! An adjustable‐porosity plastic crystal electrolyte (PCE) has been fabricated to solve the problems of high resistance and limited triple‐phase boundaries in all‐solid‐state lithium‐oxygen (ASS Li‐O2) batteries. The ASS Li‐O2 battery with dense PCE and porous PCE‐based solid‐state cathode shows ultra‐low resistance (115 Ω), large capacity (5963 mAh g−1), good rate capability, and long cycle life (130 cycles) at 32 °C.
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•Fe3O4@C/CNFs catalysts could reduce Fe leakage and avoid agglomeration.•Complete ibuprofen degradation could be achieved in the activated PS system.•Sulfate and hydroxyl radicals ...contributed principally to ibuprofen degradation.•Based on the identified intermediates, the degradation pathways were proposed.
Heterogeneous catalysts for persulfate activation were synthesized using ferrocene and carbon nanofiber as precursor by one-pot hydrothermal method and their performances of catalysts for persulfate activation were evaluated via ibuprofen degradation efficiencies. The structure of the catalyst was identified as carbon encapsulated Fe3O4 grafted on carbon nanofibers (Fe3O4@C/CNFs) by multiple characterization methods. The CNF supporter could greatly reduce the magnetization of Fe3O4 and increase the coercivity, which effectively avoided agglomeration. The specific surface area of the Fe3O4@C/CNFs was determined as 65.36 m2/g. The Fe3O4@C/CNFs exhibited high catalytic performances for persulfate activation and ibuprofen could be completely removed in the system with an activation energy of 23.51 kJ/mol. The degradation efficiencies increased with the Fe loading, catalyst dosage and persulfate concentration. The catalysts also showed stable activity with minimal metal leaking over five cycles. Hydroxyl and sulfate radicals were verified by spin-trapping and scavenger experiments and principally contributed to ibuprofen degradation. The possible ibuprofen degradation pathways were elucidated based on intermediate analysis. This work would promote the applications of sulfate radical based advanced oxidation processes for the environmental remediation.
With the rapid development of wearable and portable electronics, flexible and stretchable energy storage devices to power them are rapidly emerging. Among numerous flexible energy storage ...technologies, flexible batteries are considered as the most favorable candidate due to their high energy density and long cycle life. In particular, flexible 1D batteries with the unique advantages of miniaturization, adaptability, and weavability are expected to be a part of such applications. The development of 1D batteries, including lithium‐ion batteries, zinc‐ion batteries, zinc–air batteries, and lithium–air batteries, is comprehensively summarized, with particular emphasis on electrode preparation, battery design, and battery properties. In addition, the remaining challenges to the commercialization of current 1D batteries and prospective opportunities in the field are discussed.
The latest advances in flexible 1D batteries, including metal‐ion batteries and metal–air batteries, are summarized, with particular emphasis on electrode preparation, battery design, and electrochemical and mechanical properties. Additionally, future perspectives on and remaining challenges to the practical application of 1D batteries are also discussed to promote the commercialization of 1D batteries.
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