Smart Interfacing between Co-Fe Layered Double Hydroxide and Graphitic Carbon Nitride for High-efficiency Electrocatalytic Nitrogen Reduction

Bimetallic compounds such as hydrotalcite-type layered double hydroxides(LDHs)are promising electrocatalysts owing to their unique electronic structures.However,their abilities toward nitrogen adsorption and reduction are undermined since the surface-mantled,electronegative-OH groups hinder the charge transfer between transition metal atoms and nitrogen molecules.Herein,a smart interfacing strategy is proposed to construct a coupled heterointerface between LDH and 2D g-C_(3)N_(4),which is proven by density functional theory(DFT)investigations to be favorable for nitrogen adsorption and ammonia desorption compared with neat LDH surface.The interfaced LDH and g-C_(3)N_(4) is further hybridized with a self-standing TiO_(2) nanofibrous membrane(NM)to maximize the interfacial effect owing to its high porosity and large surface area.Profited from the synergistic superiorities of the three components,the LDH@C_(3)N_(4)@TiO_(2) NM delivers superior ammonia yield(2.07×10^(−9) mol s^(−1) cm^(−2))and Faradaic efficiency(25.3%),making it a high-efficiency,noble-metal-free catalyst system toward electrocatalytic nitrogen reduction.

ZrO_(2)纳米纤维的最新进展:从结构设计到新兴应用

一维二氧化锆纳米纤维(ZrO_(2)NFs)作为一种重要的无机材料,以其独特的结构特性、优异的化学/热稳定性,以及杰出的光学/电子性能而备受关注.生物模板法、相转化法、离心纺丝法和静电纺丝法是合成ZrO_(2)NFs的简便且高度通用的方法,在隔热、空气过滤、水净化、催化剂载体、染料敏化电池和锂离子电池等新兴应用领域具有巨大的潜力.本文对多孔、中空、层状、甚至三维自组装等多种结构的ZrO_(2)NFs的合成策略进行了详细的描述和分析.此外,本文还讨论了近年来打破陶瓷脆性、构建柔性ZrO_(2)NFs的革命性进展及其变形机制.接着介绍了ZrO_(2)NFs在隔热、环境修复、催化、电池等领域的应用成果.最后,我们提供了关于ZrO_(2)NFs的全面总结、关键挑战和未来展望.本文对未来新型ZrO_(2)NFs的研究具有一定的指导意义.

Vacancy-enhanced Mo-N_(2) interaction in MoSe_(2) nanosheets enables efficient electrocatalytic NH_(3) synthesis

NH_(3) plays an essential role in human life since it is an important raw material for fertilizers,plastics and rubbers production.As an NH_(3) synthesis technology under ambient conditions,electrocatalytic N_(2) reduction reaction(NRR)has great potential to replace the energy-intensive Haber-Bosch process.The key of electrocatalytic NRR is the exploration of efficient catalysts.Transition metal Mo is promising since it exists naturally in nitrogenase due to the unique Mo-N_(2) interaction;particularly in the form of 2D material such as MoSe_(2),the surface area is maximized for more active sites.However,the NRR performance of MoSe_(2) is still unsatisfactory because Mo is only exposed at the semi-open edge,and the electronegative Se-mantled surface area remains inaccessible to N_(2).Herein,we propose a simple and effective strategy to create high-concentration Se vacancies in MoSe_(2) through heteroatom doping induced lattice strain,which effectively enhances the Mo-N_(2) interaction on the surface area.In result,high NH_(3) yield(3.04×10^(–10)mol s^(–1)cm^(–2))and Faraday efficiency(21.61%)are attained at–0.45 V vs.RHE in 0.1 mol/L Na_(2)SO_(4).

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone

To the Editor:Acoustic neuroma is the most common tumor in the cerebellopontine angle(CPA)area.The surgical approaches used for acoustic neuroma include the labyrinth,middle cranial fossa,posterior sigmoid sinus,and posterior labyrinth routes.However,regardless of the approach used to expose the tumor in the internal auditory canal(IAC),the bone around the IAC must be abraded,which inevitably exposes the surrounding air cells to damage and increases the risk of cerebrospinal fluid(CSF)leak after surgery.

From sand to fast and stable silicon anode:Synthesis of hollow Si@void@C yolk-shell microspheres by aluminothermic reduction for lithium storage

As an alloying type anode material, silicon is a promising alternative of graphitic carbon due to its high theoretical capacity and natural abundance. Developing an industrially viable silicon anode, however, is still a huge challenge because of several problems: First of all, the common process to synthesize a silicon anode is complicated, costly, and energy-intensive. Besides, the huge volume expansion, inevitable side reactions with the electrolyte, and low intrinsic conductivity of silicon are eventually responsible for the poor cyclability and unsatisfactory rate capability. Herein, we aim to address these issues by proposing synthesis of hollow Si@void@C yolk-shell microspheres from sand by low-temperature aluminothermic reduction, which energetically combines a cost-effective silicon source with an energy-efficient, highyield methodology. The hollow Si@void@C yolk-shell microspheres effectively accommodate the diffusion-induced stress by providing the hollow interior and the void space. Moreover, the carbon shell not only functions as an electrolyte-blocking layer to protect the silicon yolk from undesirable side reactions and SEI formation, but also acts as a conductive framework to reduce the resistance to electron and Li^+ ion transport. Benefiting from these synergistic effects, the hollow Si@void@C yolk-shell microspheres exhibit superior long-term cyclability and rate capability.

g-C_(3)N_(4) encapsulated ZrO_(2) nanofibrous membrane decorated with CdS quantum dots: A hierarchically structured, self-supported electrocatalyst toward synergistic NH3 synthesis

The advancement of electrocatalytic N2 reduction reaction (NRR) toward ambient NH3 synthesis lies in the development of more affordable electrocatalysts than noble metals. Recently, various nanostructures of transition metal compounds have been proposed as effective electrocatalysts;however, they exist in the form of loose powders, which have to be immobilized on a matrix before serving as the electrode for electrolysis. The matrix, being it carbon paper, carbon cloth or metal foam, is electrocatalytically inactive, whose introduction inevitably raises the invalid weight while sacrificing the active sites of the electrode. Herein, we report on the fabrication of a flexible ZrO2 nanofibrous membrane as a novel, self-supported electrocatalyst. The heteroatom doping can not only endow the nanofibrous membrane with excellent flexibility, but also induce oxygen vacancies which are responsible for easier adsorption of N2 on the ZrO2 surface. To improve the electrocatalytic activity, a facile SILAR approach is employed to decorate it with CdS quantum dots (QDs), thereby tuning its Fermi level. To improve the conductivity, a g-C3N4 nanolayer is further deposited which is both conductive and active. The resulting hierarchically structured, self-supported electrocatalyst, consisting of g-C3N4 encapsulated ZrO2 nanofibrous membrane decorated with CdS QDs, integrates the merits of the three components, and exhibits a remarkable synergy toward NRR. Excellent NH3 yield of 6.32 × 10−10 mol·s−1cm−2 (−0.6 V vs. RHE) and Faradaic efficiency of 12.9% (−0.4 V vs. RHE) are attained in 0.1 M Na2SO4.

Multi-dimensionally ordered, multi-functionally integrated r-GO@TiO2（B）@Mn304 yolk-membranc shell superstructures for ultrafast lithium storage

TiO2（B） is an attractive new anode candidate for lithium-ion batteries （LIBs） due to its unique and highly desirable properties, including high structural integrity, long cycle life, and low cost. However, despite these merits, its inherent slow lithium and electron transport kinetics hinder its practical application to LIBs. Here, we propose a novel, simple route towards multi-dimensionally ordered, multi-functionally integrated reduced graphene oxide （r-GO）@TiO2（B）@Mn304 yolk-membrane-shell superstructures in which r-GO nanosheets, TiO2（B） nanosheets, and Mn304 nanoparticles are hierarchically organized to achieve remarkable synergistic interactions. This hybridization design is fundamentally bilateral in nature, aiming to overcome the conductivity and capacity deficiencies of TiO2（B） simultaneously. The resulting r-GO@TiO2（B）@Mn304 yolk-membrane- shell superstructures have great potential as advanced anode materials for ultrafast lithium storage, delivering a strikingly high reversible capacity of 662 mA.h-g-1 at 500 mA-g^-1 after 500 charge-discharge cycles.

GO/PVA nanocomposites with significantly enhanced mechanical properties through metal ion coordination

In this study,a simple and efficient way is demonstrated to create strong interfacial interaction between graphene oxide(GO)filler and poly(vinyl alcohol)(PVA)matrix through metal ion coordination.The coordination bonding provides efficient load transfer during the tensile process,and enhances the mechanical properties of the nanocomposites significantly.After being coordinated with Cu(Ⅱ)ions,GO/PVA composites show much higher Young’s moduli and yield stresses than pure PVA and noncoordinated GO/PVA.UV–vis and FTIR spectra are performed to confirm the successful coordination between GO and PVA.Ethylene diamine tetraacetic acid disodium salt(EDTA-2 Na)is used to confirm the important role of coordination in enhancing the composites.This research provides a new approach to manufacture polymer-matrix nanocomposites with significantly improved mechanical performances.

Pt/TiO_(2–x) nanofibrous aerogel for effective nitrogen reduction: A simple strategy for simultaneous Pt formation and TiO_(2–x) vacancy engineering

Electrocatalysis plays an increasingly important role in converting atmospheric molecules(e.g.,N_(2),CO_(2) and H_(2)O)to value-added products(e.g.,NH_(3),C_(2)H_(4)and H_(2)).However,developing a simple strategy for preparing catalysts with high performance for the effective conversion of clean energy is still full of chal-lenges.Herein,we describe a straightforward,one-step reduction method to achieve the formation of Pt nanoparticles(NPs)and the vacancy engineering of TiO_(2-x)nanofibers(NFs)simultaneously,which can be accomplished in 5 min.Furthermore,a Pt/TiO_(2-x)nanofibrous aerogel(NA)with an ordered cellular archi-tecture is prepared through a directional freezing technology.The Pt/TiO_(2-x)NA with excellent mechanical properties can be made into a self-supporting electrode for electrocatalytic N_(2)reduction reaction(NRR),showing high NH_(3) yield rate(4.81×10^(-10)mol/s cm^(-2))and Faraday efficiency(14.9%)at-0.35 V vs.RHE.

Planar Magnetic Integrated Harmonic Filter with Reduced EMI Noise

Through the analysis of the circuit structure and electromagnetic interference(EMI)conduction path,the structure of the traditional harmonic filter is optimized so that it has the ability to suppress EMI.Using the structure of planar magnetic integration not only ensures the basic harmonic suppression ability of the harmonic filter,but also improves the EMI suppression effect.With a single-phase voltage source 500-W SiC inverter as the platform,the feasibility and effectiveness of the design scheme are experimentally verified.The results indicated that the planar magnetic integrated harmonic EMI filter satisfies the design requirements.Additionally,the proposed planar magnetic integration scheme can significantly reduce the volume and weight of the filter and increase the power density of the entire system.