Inert Atmosphere Protection Research Articles

Ultrafine-grained refractory high-entropy alloy with oxygen control and high mechanical performance

Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bottleneck in achieving high mechanical performance. Creating a large number of clean grain boundaries in refractory high-entropy alloys is a challenge. In this study, an ultrafine-grained (UFG) NbMoTaW alloy with high grain-boundary cohesion was prepared by powder metallurgy, taking advantages of rapid hot-pressing sintering and full-process inert atmosphere protection from powder synthesis to sintering. By oxygen control and an increase in the proportion of grain boundaries, the segregation of oxygen and formation of oxides at grain boundaries were strongly mitigated, thus the intrinsic high cohesion of the interfaces was preserved. Compared to the coarse-grained alloys prepared by arc-melting and those sintered by traditional powder metallurgy methods, the UFG NbMoTaW alloy demonstrated simultaneously increased strength and plasticity at ambient temperature. The highly cohesive grain boundaries not only reduce brittle fractures effectively but also promote intragranular deformation. Consequently, the UFG NbMoTaW alloy achieved a high yield strength even at elevated temperatures, with a remarkable performance of 1117 MPa at 1200 °C. This work provides a feasible solution for producing refractory high-entropy alloys with low impurity content, refined microstructure, and excellent mechanical performance.

Modular Assembly of Pyrrolo[3,4-c]isoquinolines through Rh-Catalyzed Cascade C-H Activation/Annulation of O-Methyl Aryloximes with Maleimides.

An efficient and practical strategy for the construction of pyrrolo[3,4-c]isoquinolines via Rh(III)-catalyzed cascade C-H activation and subsequential annulation process from easily available O-methyl aryloximes and maleimides has been disclosed. This facile protocol does not require any inert atmosphere protection with good efficiency in a low loading of catalyst and exhibits good functional group tolerance and broad substrate scope. Notably, the as-prepared products show potential photophysical properties.

A rhodium-catalyzed cascade C-H activation/annulation strategy for the expeditious assembly of pyrrolidinedione-fused 1,2-benzothiazines.

A cascade annulation strategy triggered by rhodium(III)-catalyzed C-H activation has been reported for the expeditious assembly of pyrrolidinedione-fused 1,2-benzothiazines from free NH-sulfoximines with maleimides under mild conditions. Without the need for inert atmosphere protection, a broad range of sulfoximines with maleimides were well tolerated, producing diverse fused-thiazine derivatives in moderate to good yields. Additionally, the late-stage transformation of the target product demonstrated the potential synthetic value of this protocol.

Cascade Annulation Strategy for Expeditious Assembly of Hydroxybenzo[c]chromen-6-ones and Their Photophysical Property Studies.

A 1,8-diazabicyclo[5.4.0]undec-7-ene-promoted cascade double-annulation of ortho-alkynyl quinone methide (in situ generated from modular propargylamine) for constructing of 2-aryl-4-hydroxybenzo[c]chromen-6-ones is developed. This synthetic strategy offers remarkable operational simplicity as it allows the use of benchtop-grade solvents without the need for predrying measures and inert atmosphere protection. Additionally, it demonstrates good functional group compatibility. The photophysical properties of these compounds were also examined, revealing bright fluorescence with high quantum yields.

Air‐Processed Blue Perovskite Light‐Emitting Diodes Enabled by Manipulation of Adsorbed‐Moisture‐Dominated Crystallization Kinetics

AbstractThe fabrication of blue perovskite light‐emitting diodes (PeLEDs) in air conditions promises to liberate the manipulation procedures from the protection of inert atmosphere in the glovebox, which will remarkably promote the commercialization proceeding of perovskite‐based optoelectronic devices in display applications. However, achieving air‐processed blue PeLEDs in the interference of moisture meets great challenges in crystallization kinetics control. Herein, it is proposed that substrate‐adsorbed moisture dominates the perovskite crystallization kinetics during the fabrication in air, and the limited moisture from nonhygroscopic substrate inhibits the nucleation of the large‐n phase and allows the growth of the small‐n phase, thus yielding blue quasi‐2D perovskite films in a wide moisture range of 10–50% relative humidity. Then, air‐processed blue PeLEDs are successfully achieved for the first time, showing a brightness of 968 cd m−2, external quantum efficiency of 2.54% at stable peak emission of 483 nm, as well as an outstanding operating stability of 546 s at a peak brightness of 45 cd m−2, which are favorably competitive with PeLEDs fabricated in the glovebox. This work provides a guideline for air‐processed blue PeLEDs fabrication, which paves the way for air‐processed PeLEDs in further application of commercialization display.

Superfast desulfurization for protein chemical synthesis and modification

Superfast desulfurization for protein chemical synthesis and modification

Rapid and low temperature sintering bonding using Cu nanoparticle film for power electronic packaging

It is of great interest but very difficult to achieve both rapid (few minutes) and low temperature (<200 °C) sintering bonding using Cu nanoparticles, which is mainly due to the diffusion dominated process and complex organics in the nanoparticle paste. In present work, a copper nanoparticle film (CNF) fabricated by pulsed laser deposition (PLD) has been developed. Under the reduction of ethylene glycol (EG) and protection of inert atmosphere, it can be sintering bonded at even 140 °C, having adequate shear strength higher than that of Pb-5Sn. A remarkable high strength of 65 MPa for Cu-DBC joints and 50 MPa for Si-DBC joints were achieved when sintered at 250 °C for only 1 min. The rapid and low temperature sintering of CNF is mainly attributed to the efficient oxide film removal by EG at low-temperature, since it is an organic free dry film without the complex organics which decompose or evaporate at high temperature. The relationships among joint strength, porosity of microstructure and interfacial connection ratio have also been discussed.

Direct Construction of Quinoxaline Derivatives from Vicinal Diols and o‐Nitroanilines via NaOH‐Mediated Intermolecular Cascade Redox and Annulation Reactions

AbstractAn alkali base, such as NaOH, alone can effectively mediate the intermolecular cascade redox and annulation reactions of o‐nitroanilines with vicinal diols, providing an efficient transition metal‐free method for direct construction of the useful quinoxaline derivatives. This method tolerates a wide range of substrates, can be readily performed in open air and scaled up for gram synthesis of several pharmaceutically and biologically active quinoxaline derivatives. Studies revealed that the nitro group works as the internal oxidant and the diols the reductant. Possible reaction paths were also proposed based on control reactions. For simple operation of the reactions, requiring no external reducing and oxidizing reagents, no inert atmosphere protection and no transition metal catalysts/ligands but only a water‐soluble alkali base, and having no transition metal residue contaminant in the products, this method may be a relatively greener and practical way for construction of the quinoxaline skeleton, especially for the pharmacy‐ or biology‐oriented quinoxaline derivatives.

Gold Self‐Relay Catalysis Enabling [3,3]‐Sigmatropic Rearrangement/Nazarov Cyclization and Allylic Alkylation Cascade for Constructing All‐Carbon Quaternary Stereocenters

Comprehensive SummaryMolecular scaffolds endowed with all‐carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules. However, efficient construction of this type of structure units is full of challenge due to their congested chemical environment. Herein, we report a new gold(I) self‐relay catalysis merging [3,3]‐sigmatropic rearrangement/Nazarov cyclization with allylic alkylation starting from 1,3‐enyne acetates and allylic alcohols, producing a wide range of synthetically important allyl cyclopentenones with an all‐carbon quaternary stereocenter in good yields under mild conditions. This protocol demonstrates the precise control of regioselectivity, high functional group tolerance of substrates and the low loading of gold catalyst without inert atmosphere protection, providing a catalytic and efficient entry to all‐carbon quaternary stereocenters

Chemical bath deposition of AgBiS2 films for visible and X-ray detection

AgBiS2 possesses high absorption coefficient from ultra-violet to near-infrared, decent charge transport and superior materials stability, which has emerged as a promising candidate in the field of optoelectronics. However, efficient AgBiS2-based devices are mostly based on AgBiS2 quantum dots and precursor methods, which require either long preparation time and complex synthetic steps or inert atmosphere protection. To address these issues, we developed a novel and facile chemical bath deposition approach to deposit highly crystallized, uniform AgBiS2 thin films with decent optoelectronic properties. We also fabricated AgBiS2 heterojunction photodetectors based on this method, and achieved high responsivity covering the whole range of visible and near-infrared, fast response speed of ∼960 ns, and high specific detectivity of 8 × 1011 Jones and outstanding device stability. More importantly, we first demonstrated the device performance under X-ray illumination and observed decent sensitivity, implying great potential for low-cost, solution-processable X-ray detectors.

Iridium-Catalyzed Asymmetric Transfer Hydrogenation of Quinolines in Biphasic Systems or Water.

An asymmetric transfer hydrogenation (ATH) of quinolines in water or biphasic systems was developed. This ATH reaction proceeds smoothly without the need for inert atmosphere protection in the presence of a water-soluble iridium catalyst, which bears an easily available aminobenzimidazole ligand. This ATH system can work at a catalyst loading of 0.001 mol % (S/C = 100 000, turnover number (TON) of up to 33 000) under mild reaction conditions. The turnover frequency (TOF) value can reach as high as 90 000 h-1. A variety of quinoline and N-heteroaryl compounds are transformed into the desired products in high yield and up to 99% enantiomeric excess (ee).

One-pot synthesis method of copper nanoparticles in air

A feasible one-pot synthesis method for the preparation of copper nanoparticles under ambient atmosphere is put forward. Copper oxide and D-isoascorbic acid were chosen as the copper precursor and mild reducing agent, respectively. Oleylamine and octylamine were selected as the capping agents. The effects of the amount and alkyl chain length of capping agent on the synthesis of copper nanoparticles were studied. Antioxidised copper nanoparticles were prepared successfully without the protection of inert atmosphere. The minimum average size of obtained copper nanoparticles was 149 ± 11 nm.

Facile Assembly of Carbazolyl-Derived Phosphine Ligands and Their Applications in Palladium-Catalyzed Sterically Hindered Arylation Processes

Phosphine ligands embodying a carbazolyl motif have been found to be successful in many palladium-catalyzed biaryl syntheses and direct C–H bond arylation processes. Here, a practical scaled-up synthesis of a series of carbazolyl-derived phosphine ligands, the PhenCarPhos series, is described. The original protocol for accessing the target ligand skeleton via aromatic C–N bond formation is limited by the use of a substoichiometric amount of copper salt and diamine catalysts, which both add cost and generate purification problems (significant amounts of side products and copper residues). In order to develop a more attractive and scalable synthetic pathway, a simple nucleophilic substitution method was attempted involving simple heating of 1-bromo-2-fluorobenzene, a carbazole derivative, and KOH in DMF without inert atmosphere protection. This route enables the large-scale synthesis of the desired ligand skeletons and minimizes the association of inseparable reduction side products. Particular examples of the use of these ligands in Pd-catalyzed sterically hindered arylation processes are also shown.

An Autotransferable g‐C3N4 Li+‐Modulating Layer toward Stable Lithium Anodes

Commercial deployment of lithium anodes has been severely impeded by the poor battery safety, unsatisfying cycling lifespan, and efficiency. Recently, building artificial interfacial layers over a lithium anode was regarded as an effective strategy to stabilize the electrode. However, the fabrications reported so far have mostly been conducted directly upon lithium foil, often requiring stringent reaction conditions with indispensable inert environment protection and highly specialized reagents due to the high reactivity of metallic lithium. Besides, the uneven lithium-ion flux across the lithium surface should be more powerfully tailored via mighty interfacial layer materials. Herein, g-C3 N4 is employed as a Li+ -modulating material and a brand-new autotransferable strategy to fabricate this interfacial layer for Li anodes without any inert atmosphere protection and limitation of chemical regents is developed. The g-C3 N4 film is filtrated on the separator in air using a common alcohol solution and then perfectly autotransferred to the lithium surface by electrolyte wetting during normal cell assembly. The abundant nitrogen species within g-C3 N4 nanosheets can form transient LiN bonds to powerfully stabilize the lithium-ion flux and thus enable a CE over 99% for 900 cycles and smooth deposition at high current densities and capacities, surpassing most previous works.

One‐Step Synthesis of the N and P Co–Doped Nest‐Like Mesoporous Carbon by a Microwave‐Assisted Ultra‐High Temperature Solvothermal Method for Supercapacitor Application

AbstractHerein, we report a microwave‐assisted ultra‐high temperature solvothermal method for fabricating a nitrogen and phosphorus co‐doped nest‐like mesoporous carbon under ambient atmosphere. The reported method exhibits high energy efficiency, ultra‐fast carbonization rate, and inert atmosphere protection free fabrication process. The carbonization process of precursor completes in 5∼10 min, and no apparent increase for surface oxygen content is observed for the obtained material even it is fabricated under oxygen‐riched ambient atmosphere. The obtained material fabricated by the reported method exhibits a nest‐like mesoporous morphology and high specific surface area (up to 922 m2 g−1), which nitrogen and phosphorus doping content reaches up to 3.45 and 1.26 at.%, respectively. When used as an electrode material for supercapacitor, the obtained material exhibits good capacitive performance, which specific capacitance reaches up to 171 F g−1, and more than 89.9% of initial capacitance is retained even under a high current density of 20 A g−1, the capacitance retention rate reaches up to 96.2% after 5000 charge/discharge cycles.

Direct Synthesis and Anion Exchange of Noncarbonate-Intercalated NiFe-Layered Double Hydroxides and the Influence on Electrocatalysis

Metal-layered double hydroxides (LDHs), a family of versatile layered materials recently popular as earth-abundant oxygen evolution reaction (OER) catalysts, allow for both metal substitution and interlayer anion exchange without disrupting the two-dimensional (2D) crystal structure, although the ubiquity of carbonate anions is challenging to avoid. Here, we use hydrothermal synthesis in modified solvents with triethanolamine to directly synthesize bulk NiFe LDHs with carbonate, chloride, and sulfate interlayer anions without inert atmosphere protection. Structural characterizations by X-ray diffraction, infrared spectroscopy, and energy-dispersive X-ray spectroscopy confirm the anion composition. Electrochemical characterization shows that LDHs with these three anions display similar OER catalytic performance after surface area normalization, consistent with observed anion exchange to carbonate in alkaline electrolyte under ambient conditions. However, dodecyl sulfate-intercalated NiFe LDHs prepared by a...

Stability and protection of nanowire devices in air

Nanowire devices have attracted considerable attention because of their unique structure and novel properties, and have opened up significant development opportunities. However, not many studies have focused on their stability and durability under practical conditions, which limits the rapid development of real applications. Herein, we systematically investigate three different treatments,polymer coating, inert atmosphere protection, and thickness-induced self-protection, to protect the tellurium nanowire devices from oxidation when exposed to open air. The degree of oxidation was monitored by examining changes in the valence states of tellurium element and in the morphology of the nanowires. After the protective treatments, the tellurium nanowire devices showed improved stability and remained stable even after 800 days of storage. This work highlights the importance of investigating the stability of nanowire devices, especially for their practical applications.

Surface oxidation of as-deposit uranium film characterized by X-ray photoelectron spectroscopy

Uranium film is a main functional component to realize the high efficiency conversion of laser to X-ray in the study on laser inertial confinement fusion. It also has important applications in relevant physics experiments. Due to its active chemical properties, the metal uranium film is extremely difficult to preserve in the atmosphere. A variety of methods may help to avoid the oxidation of uranium film, such as coating protective layer, vacuum or inert atmosphere protection. But under these conditions, the oxidation property of uranium film still needs experimental investigation. In this paper, the oxidation processes of uranium films under different atmospheres are studied by X-ray photoelectron spectroscopy (XPS) and depth profiling. Firstly, uranium films and gold-uranium multilayer films are prepared by ultra-high vacuum magnetron sputtering deposition, and then they are exposed to atmosphere, high purity argon and ultrahigh vacuum for a period of time. Finally, the distributions and valence states of oxygen and uranium elements are investigated by XPS depth profiling. The oxidation mechanism is analyzed according to the oxidation products and the microstructure characteristics of samples. The results show that the oxygen element is undetectable in the initial films. In the Au-U multilayer film, the protective ability of Au layer is greatly weakened by the micro-defects. The defect is not only the micro channel of oxygen entering into the sample directly, but also the origin of the interlaminar cracks at the Au/U interface. In about three weeks, the uranium layer is severely oxidized and large area lamination occurs. The oxidation products consist of a dense oxide thin film on uranium surface and corrosion pitting around the defects, which are mainly UO2. For the pure uranium film, the surface of the film is completely oxidized when it is exposed to high purity argon only for 6 h. The UO2 layers with different thickness values are formed on their surface, which is due to the rapid diffusion of oxygen atoms at the columnar grain boundaries of the film. After the sample is exposed to the ultra-high vacuum for 12 h, UO2 layer with a thickness of less than 1 nm is generated on the surface of the pure uranium film. In the etching of oxide by argon ion beams, the preferential sputtering effect of O is produced, and UO2 is reduced into non-stoichiometric UO2-x. The effect of preferential sputtering is weakened with the decrease of oxide content. When the oxide content is less than 10%, the reduction of UO2 can hardly be detected.

Ultra-facile fabrication of phosphorus doped egg-like hierarchic porous carbon with superior supercapacitance performance by microwave irradiation combining with self-activation strategy

Herein, we report an ultra-facile fabrication method for a phosphorus doped egg-like hierarchic porous carbon by microwave irradiation combining with self-activation strategy under air atmosphere. Comparing with the traditional pyrolytic carbonization method, the reported method exhibits incomparable merits, such as high energy efficiency, ultra-fast and inert atmosphere protection absent fabrication process. Similar morphology and graphitization degree with the sample fabricated by the traditional pyrolytic carbonization method under inert atmosphere protection for 2 h can be easily achieved by the reported microwave irradiation method just for 3 min under ambient atmosphere. The samples fabricated by the reported method display a unique phosphorus doped egg-like hierarchic porous structure, high specific surface area (1642 m2 g−1) and large pore volume (2.04 cm3 g−1). Specific capacitance of the samples fabricated by the reported method reaches up to 209 F g−1, and over 96.2% of initial capacitance remains as current density increasing from 0.5 to 20 A g−1, indicating the superior capacitance performance of the fabricated samples. The hierarchic porous structure, opened microporosity, additional pseudocapacitance, high electrolyte-accessible surface area and good conductivity make essential contribution to its superior capacitance performance.

Pd/C-Catalyzed Aminocarbonylation of Aryl Iodides with Anthranils in Water Using Mo(CO)6 as the CO Source.

A convenient procedure for the synthesis of N-(2-carbonylaryl)benzamides has been developed. Through Pd/C-catalyzed aminocarbonylation of anthranils with various hindered and functionalized aryl iodides, the desired amides were afforded in moderate to good yields. The protocol is advantageous due to the recyclable Pd/C catalyst, safe Mo(CO)6 as the solid CO source, and environmentally benign water as solvent. No inert atmosphere protection is needed.