Oxygen Nitrogen Research Articles

Cyanide Functionalization and Oxygen Vacancy Creation in Ni-Fe Nano Petals Sprinkled with MIL-88A Derived Metal Oxide Nano Droplets for Bifunctional Alkaline Seawater Electrolysis.

This work investigates novel improvements in FeNi-layered double hydroxide (LDH)/MIL-88A heterocomposite for sustainable seawater electrolysis through a single-step dual functionalization process. The Fe/Ni precursor weight ratio is optimized, resulting in the formation of smaller LDH petals and nano-sized MIL-88A metal-organic framework, which transforms into clusters of Fe2O3 nanospheres within a nitrogen-functionalized carbon matrix over NiFe2O4 nano petals upon calcination. Furthermore, oxygen vacancies, and nitrogen functionalization are attained in a single step by employing thermal ammonia reduction, significantly improving the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities. Particularly the oxygen vacancy and nitrogen functionalization are found to accelerate the O─O coupling step in OER by lowering the activation barrier. Likewise, the dual functionalization promotes destabilizing the hydride intermediates in HER potentially facilitating faster proton-coupled electron transfer. Hence, the optimized electrode achieves current densities of 200mAcm-2 at overpotentials of 350 and 240mV for OER and HER respectively. The chronopotentiometry stability tests confirms the electrode's durability over 200h at 20mAcm-2 in alkaline seawater electrolyte. The optimized electrode, composed of cost-effective and environmentally friendly materials, demonstrates robustness in alkaline seawater electrolytes, positioning it as a strong candidate for practical and sustainable water electrolysis applications.

Purification mechanism of emergent aquatic plants on polluted water: A review.

Nitrogen and phosphorus inputs to surface water bodies lead to a decline in water quality and a disruption in the balance of aquatic ecosystems. Emergent aquatic plants were widely used for their high efficiency in removing nitrogen and phosphorus from surface waters. However, there was a lack of systematic analyses on the purification of surface waters by emergent aquatic plants, and the mechanism of differences in nitrogen and phosphorus removal by different plants needs to be further revealed. By preferentially selecting emergent aquatic plants, the removal effects of 15 selected aquatic plants on five pollutant indicators (total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus, and chemical oxygen demand) were analyzed at different concentrations, and the characteristics of the removal of pollutants by different aquatic plants were explored. At the same time, combined with the morphology and synergistic action of microorganisms, in-depth research on the purification mechanism of water bodies by emergent aquatic plants was conducted. Differences were found in the purification of different water-supporting aquatic plants for different concentrations of pollutants. The comprehensive evaluation results of the membership function showed that the combined purification ability of Acorus calamus, Cyperus involucratus, Iris pseudacorus and Typha orientalis was better for the conventional pollutants. This study provides an important reference for the preferential selection of emergent aquatic plants to enhance water pollution purification and further promote the progress of ecological water treatment technology.

Warming effects on the emission pathways of N2O and CH4 and the role of water column in shallow eutrophic lakes.

Shallow lakes are frequently reported to be pivotal sources of greenhouse gases (GHGs) such as methane (CH4) and nitrous oxide (N2O) to the atmosphere, and their emissions are strongly influenced by changing climate and water eutrophic state. However, the transfer of N2O and CH4 from sediments to the atmosphere and the role of the water column in shallow eutrophic lakes remain poorly understood, particularly under warming conditions. Herein, the effects of experimental warming on diffusion and ebullition emissions of N2O and CH4 from shallow lakes and the potential drivers were investigated. Results showed that 88.68% of N2O emissions depended on diffusion, while 61.60% of the CH4 was emitted by ebullition. Warming significantly stimulated N2O and CH4 emissions at the water-air interface, with CH4 (0.45eV) having a higher temperature dependence than N2O (0.25eV). Warming also shifted CH4 emission pathways from diffusion-dominated to ebullition-dominated at approximately 20°C. As a source, the water column contributed 35.33%-66.51% of N2O emissions to the atmosphere, but as a sink, it oxidized 30.00%-67.49% of the CH4 from the sediments. These were driven mainly by the eutrophic state, except for the direct effect of warming, such as the changes of dissolved oxygen, organic carbon, and ammonia nitrogen in the sediment and water column. Warming not only accelerated the GHGs emission from sediments, but also correspondingly changed the transferring processes of GHGs in the water column and then the emissions to the atmosphere. Understanding the complex interactions between climate warming and N2O and CH4 fluxes in shallow eutrophic lakes is critical for effective lake management and control of GHGs emissions.

Studying the Properties of Water Activated by Hybrid Plasma for Biological and Medical Applications

This work investigates the chemical and physical properties of water activated by Hybrid plasma, using argon gas. Two ways were used to activate the water: the first one was done by mixing the argon gas and air at atmospheric pressure at two flow rates of 0.7 and 1.0 L/min, and the second, used only atmospheric air. To study the physical and chemical properties of water, 10 cm3 of distilled water was placed in a container made of glass in the form of a dish with a diameter of 5 cm and 1 cm depth; an AC sinewave voltage of 12 kV, a frequency of 20 kHz, and power of 36 watts was used; the exposure time ranged from 1-30 minutes. The generated RONS (oxygen nitrogen reactive species) were quantified utilizing tools designed specifically for this objective. The results showed that NO2, NO3 and H2O2 concentrations increased with the exposure time but they decreased with the increases the flow rate. The water pH in both methods decreased with the exposure time until it reached 2.3; the water temperature increased reaching 51.7°C with the first method and 50.6°C with the second method. The pH increased with the storage time, and the plasma activated water (PAW) reached the natural pH value of 7 after 24 hours of storage. From these findings, it can be concluded that Hybrid plasma discharge can produce RONS that may be applied in biological applications.

Lysyl oxidase nanozyme-loaded hydrogel for sustained release and promotion of diabetic bone defect regeneration.

The process of regenerating bone injuries in diabetic presents significant challenges because lysine oxidase (LOX), a key catalytic enzyme for collagen cross-linking, is inhibited in hyperglycemia. The supplementation of LOX is constrained by inadequate sources and diminished enzymatic activity, necessitating the development of effective alternatives for enhancing bone regeneration in diabetes. Herein, we reported a lysyl oxidase nanozyme (LON), derived from the catalytic domain of LOX. LON formed a stable coordination structure with the active center Cu2+ through histidine imidazolyl nitrogen and quinone oxygen, which is consistent with the conformation of the LOX. Our findings suggested that LON demonstrated the capacity to substitute LOX in promoting collagen synthesis and biomineralization. To enable sustained LON delivery, it was incorporated into a GelMA hydrogel (GH), forming a sustained-release reservoir known as LON-GelMA hydrogel (LONGH). Mechanism of LONGH promoting bone healing to accelerate the crosslinking and maturation stage of collagen were also explored, and the 23 genes closely associated with collagen regeneration and osteogenesis were found to be upregulated. The present investigation outcomes reveal that the engineered LONGH hydrogel presents a novel, simple, and commercially viable approach for bone regeneration, offering significant potential for clinical applications.

Synthesis, structure and fluorescence of a novel zinc(II) polymer based on N-[(3-pyridine)-3-sulfonyl]-threonine

Abstract A novel zinc(II) polymer based on pyridine sulfonyl amino acid, namely [Zn(HL)(H2O)2]n·4H2O (1) (HL=(1-carboxylato-2-hydroxypropyl)(pyridin-3-sulfonyl)-threonine), was synthesized by reacting Zn(NO3)2·6H2O with H3L in a mixed solvent solution of MeCN/EtOH/H2O under acidic conditions. Single crystal X-ray diffraction analysis revealed that the polymer 1 crystallized in trigonal crystal system, space group P3121. Notably, the unit cell of the as-formed polymer 1 contains only one crystallographically independent zinc(II) ion, and the divalent anion ligand HL adopts a coordination pattern of η 1 :η 2 :μ 2. The zinc(II) central ions are connected by bridging coordination with the HL ligand through pyridyl nitrogen and carboxy oxygen atoms to form an infinite helix chain. Furthermore, numerous hydrogen bonds were observed among these chains, joining them into a 2D supramolecular network. Finally, the complex is stacked along the 31 helical axis to yield a three-dimensional supramolecular structure. Additionally, the thermal stability and photoluminescence properties of 1 were determined and discussed.

Synthesis, characterization, and crystal structures of 4-hydroxy-N’-(2-hydroxy-5-methylbenzylidene)benzohydrazide and its copper(II) complexes with antibacterial activity

A hydrazone compound 4-hydroxy-N’-(2-hydroxy-5-methylbenzylidene)benzohydrazide (HL) was prepared from the condensation reaction of 5-methylsalicylaldehyde with 4-hydroxybenzohydrazide. The compound was characterized by IR, UV-Vis, 1H NMR, and 13C NMR spectra. Reaction of HL with copper nitrate and copper chloride, respectively, afforded two new copper(II) complexes, [Cu2L2(CH3OH)2]·2NO3 (1) and [CuL(DMF)]·Cl (2). The complexes were characterized by IR and UV-Vis spectra. Structures of HL and the complexes were confirmed by single-crystal X-ray determination. The powder X-ray diffraction was performed to verify the purity of the bulk samples of the complexes. The hydrazone compound coordinates to the Cu atoms through phenolate oxygen, imino nitrogen, and carbonyl oxygen. The Cu atoms in complex 1 are in square pyramidal coordination, while that in complex 2 is in square planar coordination. The antibacterial study using the free hydrazone compound and the two copper complexes against both Gram-positive and Gram-negative bacteria are performed, the two complexes showed antibacterial activity against both Gram-positive and Gram-negative bacteria, whereas the free ligand shows no activity.

In vitro immunotoxic evaluation of herbicides in RAW 264.7 cells

ABSTRACT Weeds are a concern in agriculture and the use of herbicides constitutes an effective, efficient, and economical way to control their growth. Recent discoveries of herbicides are promising for the management of resistant weeds. However, there is a gap in the knowledge of the toxic effects of some herbicides previously reported on immune cells. The present study aimed to examine cellular immunotoxicity of three herbicides (clomazone, glyphosate, and sulfentrazone) after 96 hr incubation utilizing RAW 264.7 BALB/c mouse monocyte/macrophage-like cell line to elucidate the role of some toxicological pathways. Data demonstrated the herbicides clomazone, glyphosate, and sulfentrazone initiated a cytotoxic effect as evidenced by EC50 values of 429.2; 53.7; 866.6 mg/L, respectively. Clomazone and sulfentrazone, at all concentrations, induced excess production of reactive oxygen (ROS) and reactive nitrogen (RNS) free radicals. An immunosuppression was observed in RAW 264.7 cells after incubation with 50 or 100 mg/L glyphosate and 500 or 1000 mg/L sulfentrazone. In addition, all herbicides produced mitochondrial depolarization and decreased tumor necrosis factor-α (TNF-α) levels. This constitutes the first report of the effects of clomazone and sulfentrazone on RAW 264.7 cells, including reduced TNF-α levels, indicating the adverse influence of herbicides on the immune system.

Molecular Design and Theoretical Study on Dioxadiazine Energetic Compounds Involving Intramolecular Hydrogen Bonds

ABSTRACTThe high nitrogen and high oxygen content of energetic dioxadiazine compounds makes them exhibit high detonation performance and good stability, showing possible application in both military and civilian fields. Energetic dioxadiazine compounds with intramolecular hydrogen bonds were designed and optimized, while introducing —NH2, —NHNO2, —CH3, —NO2, and —OH as modified groups. The bond order, density, enthalpy of formation, stability, detonation performance and inter/intramolecular interactions were analyzed. Results showed that the skeleton of 1,4,2,6‐dioxadiazine and 1,4,2,5‐dioxadiazine had good stability and symmetrical structure. Analysis of bond length revealed the strong hydrogen bonding between the hydroxyl group and dioxadiazine ring. The introduction of —NH2 and —OH groups proved beneficial in increasing molecular planarity. Bond order analysis, molecular electrostatic potential (ESP) analysis and detonation parameter calculations showed that B5 and C5 have good stability and detonation properties. Crystal structure prediction suggested that B5 would most likely crystallize in monoclinic (P21 space group) while C5 would crystallize in orthorhombic (Pbca space group). Hirshfeld surface analysis indicated strong O···H and N···H interactions for compounds B5 and C5. The above results have a positive promoting effect on obtaining high‐energy dioxadiazine compounds with high stability.

Palladium(II) complexes containing andrographolide appended N,O heterocyclic chelators: Investigation of anti-oxidant, anti-cancer and apoptotic activities.

A series of new Pd(II) complexes were synthesized from the reaction of andrographolide appended hydrazide derivatives with potassium tetrachloropalladate K2[PdCl4]. The formation of the complexes was confirmed through structural assessments conducted using various spectroscopic techniques. From the spectral studies we confirmed that the ligands coordinated to Pd(II) ion via amine nitrogen and enone oxygen. The complexes were assessed for their antioxidant properties, demonstrating significant radical scavenging activity with a series of free radicals such as 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS•+), Super oxide (O2-) and Nitric oxide (NO•) radicals compared with standard antioxidants. Moreover, in vitro antiproliferative investigations conducted on A549 (human lung cancer) and HeLa (human cervical cancer) cell lines revealed significant cytotoxicity of the complexes, with lower IC50 values compared to the standard metallo-drug cisplatin. Morphological alterations observed in HeLa and A549 cells when treated with IC50 concentrations of the complexes, as examined through Acridine Orange-Ethidium Bromide (AO-EB) and 4',6-diamidino-2-phenylindole (DAPI) staining techniques, indicated cell death via apoptosis. Biological studies indicated that AGC-Pd exhibited superior activity among others, further the percentages of the apoptotic and necrotic cells were determined by flow cytometric technique.

An experimental study on water purification performance of modified volcanic rock ecological concrete

Eco-concrete is an engineered porous material, often used in pervious pavement and slope protection. Volcanic rock, due to its loose and porous structure, can absorb pollutants and improve the performance of eco-concrete. Here, this study determined the performance of eco-concrete modified with different contents of volcanic rock in sewage purification. The results showed that eco-concrete purified sewage, and that adding volcanic rock further improved the removal capacity of total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) by 34.1, 47.3, and 6%, respectively. The water purification mechanism of volcanic rock eco-concrete (VREC) was mainly physical water absorption (mechanical retention) and microbial degradation. With the increase in the content of cement slurry, the adsorption amount decreased, porosity decreased, and strength increased, gradually not meeting the engineering application requirements. Therefore, the high porosity volcanic rock eco-concrete (VREC) had the best water purification performance. The result conclude that eco-concrete should be prepared with an admixture of volcanic rock with 30% porosity for the best sewage purification results.

Structural Categorization of Adenine, Guanine, and Xanthine Derivatives Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry with 5-Nitrosalicylic Acid and 1,5-Diaminonaphtalene.

In this study, we analyzed purine derivatives using multimatrix variation matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) with α-cyano-4-hydroxycinnamic acid (CHCA), 1,5-diaminonaphtalene (DAN), 5-formylsalicylic acid (FSA), and 5-nitrosalicylic acid (NSA) as matrices. Further, we focused on the abstraction/attachment of hydrogen from/to analytes and detected [M - H]+, [M + 2H]+• and/or [M + 3H]+ in MALDI MS spectra of compounds containing nitrogen and/or carbonyl oxygen. Although [M - H]+ generation of purine compounds in MALDI MS with conventional matrices was challenging, NSA-MALDI MS effectively yielded the [M - H]+species of purine derivatives compared with CHCA, FSA, and DAN, and the [M - H]+/[M + H]+ ratios reflected their structures, such as the substituting groups and positions. We speculated that the molecular ion [M]+• generated and the subsequent hydrogen radical abstraction proceeded by NSA matrix from the α-carbon of the amine group. The nitro group (-NO2) of NSA can withdraw hydrogen radicals in photochemical reactions. The [M - H]+ of adenosine, guanosine, and inosine suggested that hydrogen abstraction occurred in the ribose unit. The xanthine isomer of paraxanthine was distinguished from those of theophylline and theobromine using their [M - H]+/[M + H]+ ratios obtained with NSA-MALDI MS. Additionally, [M + 2H]+• generated in DAN-MALDI MS of xanthine derivatives due to their carbonyl groups. The relative abundances of [M + 2H]+• of xanthine derivatives were much higher than those of the other purine derivatives such as adenine derivatives which generated [M + 3H]+ in their DAN-MALDI MS. DAN induced the hydrogen attachment of purine compounds because the amine group (-NH2) of DAN can give hydrogen radicals in photochemical reactions. NSA- and DAN-MALDI MS characterized purine derivatives and were useful for their structure categorization.

Synthesis, Characterization and X-Ray Crystal Structures of Schiff Base Cadmium(II) and Nickel(II) Complexes with Antibacterial Activity

Two isostructural mononuclear cadmium(II) and nickel(II) complexes [Cd(HL)2(NCS)2]∙4CH3OH (1) and [Ni(HL)2(NCS)2]∙4CH3OH (2), where HL is the zwitterionic form of the Schiff base 2,4-difluoro-6-[(2-pyrrolidin-1-ylethylimino)methyl]phenol (HL), were prepared and characterized by elemental analysis, infrared and electronic spectroscopy, as well as X-ray single crystal determination. In both complexes the metal atoms are in octahedral coordination. The Schiff base ligands are coordinate to the metal atoms through phenolate oxygen and imino nitrogen. Molecules of the complexes are stabilized by hydrogen bonds. The biological assay indicates that the complexes have good antimicrobial activities on the bacteria strains Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus.

Modeling aerobic granules in continuously flowing wastewater-treatment processes.

Continuously flowing wastewater-treatment processes can be configured for biological and physical selection to form and retain large biological aggregates (LBAs), along with suspended biomass that contains ordinary biological flocs and biomass that has detached from the LBAs. Suspended biomass and LBAs have different solids residence times (SRTs) and mass-transport resistances. Here, mathematical sub-models that describe metabolic processes, a 1-D biofilm, and spherical carriers that can migrate throughout a wastewater-treatment process were combined to simulate a full-scale demonstration train having anaerobic, anoxic, and oxic zones, as well as side-stream enhanced biological phosphorus removal. Hydrocyclones were utilized for physical selection. Simulation results and experimental observations agreed for soluble chemical oxygen demand, nitrogen, and phosphorus removals, as well as mixed liquor concentration and characteristics. The model outputs demonstrated that suspended biomass was responsible for most of the transformations in the bioreactor, but LBAs contributed importantly to P accumulation as polyphosphate. The simulated LBAs accumulated a higher density of phosphorus-storing bacteria, polyphosphate, and total- and protein-extracellular polymeric substances (EPS), particularly near their core. Protein-EPS accumulated near the substratum because protein-EPS hydrolyzed more slowly than carbohydrate-EPS, while the SRT in each layer increased from the surface layer to the layer adjacent to the LBA core. PRACTITIONER POINTS: Combined models well represented observed solids components in a full-scale demonstration train as A2O with S2EBPR. Simulations described aerobic-granule structure and function consistent with what is known about aerobic granules in BNR processes. Suspended biomass dominated most of the simulated transformation rates, but the LBAs accumulated ~2000 mg P/L as polyphosphosphate. The simulated aerobic granules did not intensify WWT overall but should have improved the net solids-settling characteristics. Aerobic granules had more EPS than the suspended biomass and protein-EPS accumulated inside the LBA by slower hydrolysis kinetics.

Controlled reconstruction of metal-organic frameworks via coordination environment tuning as oxygen evolution electrocatalysts.

During the oxygen evolution reaction (OER), metal-organic framework (MOF) catalysts undergo structural reorganization, a phenomenon that is still not fully comprehended. Additionally, designing MOFs that undergo structural reconstruction to produce highly active OER catalysts continues to pose significant challenges. Herein, a bimetallic MOF (CoNi-MOF) with carboxylate oxygen and pyridine nitrogen coordination has been synthesized and its reconstruction behavior has been analyzed. The CoNi-MOF electrocatalyst attains a current density of 10 mA cm-2 with a minimal overpotential of just 250 mV, along with a Tafel slope of 91.57 mV dec-1, which is relatively low. After undergoing CV cycling tests, changes were observed in its catalytic activity, as well as in the microstructure and electrochemically active surface area, which are related to its activity. Importantly, in situ Raman analysis indicates that during the electrocatalytic process, the MOFs undergo a transition to MOOH, signifying the occurrence of reconstruction. Notably, compared to monometallic MOFs, bimetallic MOFs undergo reconstruction at lower voltage and with a faster reconstruction rate. Further analysis has revealed that the electrochemical reconstruction rate of the Co-N/O coordination mode at the active center is higher than that of Ni-N/O, playing a crucial role in enhancing OER activity. This study underscores the significance of the reconstruction strategy in enhancing the activity of MOF catalysts, providing new insights for the development of high-activity materials.

CHEMICAL OXYGEN DEMAND AND NITROGEN REMOVAL IN DISGESTED BLACKWATER BY FEAMMOX PROCESS

CHEMICAL OXYGEN DEMAND AND NITROGEN REMOVAL IN DISGESTED BLACKWATER BY FEAMMOX PROCESS

Analysis of wall catalytic effects on magnetohydrodynamic control of high-temperature non-quilibrium flow field

In the re-entry process of the vehicle into the atmosphere, the high-temperature environment, induced by the compression of the strong shock wave and viscous retardation, is created around the head of a vehicle. These generate a conductive plasma flow field, which provides a direct working environment for the application of magnetohydrodynaimic (MHD) control technology. Numerical simulations based on thermochemical non-equilibrium MHD model are adopted to analyze the surface heat flux of an orbital reentry experiment (OREX) vehicle. The influences of wall catalytic conditions on the aerothermal environment under different flight conditions are discussed. In addition, the control mechanism of an external magnetic field on high-temperature thermochemical non-equilibrium flow field is analyzed. The results show that the distribution of surface heat flux monotonically increases with the catalytic recombination coefficient increasing, and the surface heat flux rises and then drops with the flight altitude decreasing. Moreover, the wall catalytic properties significantly affect the efficiency of MHD control technology, and the total heat flux is closely related to the accumulation of atomic components, diffusion gradient and temperature gradient near the wall region. With an external magnetic field applied, the accumulation of oxygen atoms and nitrogen atoms near the wall can be reduced. Moreover, the Lorentz force can increase the shock standoff distance, and then reduce the component diffusion gradient and wall temperature gradient. Under three different wall catalytic conditions, the ability to control the surface heat flux MHD is ranked from strong to weak as fully catalyzed, partially catalyzed and non-catalyzed.

Effect of salinity on nitrogen removal performance, enzymatic activity and metabolic pathway of Chlorella pyrenoidosa treating aquaculture wastewater.

The nitrogen removal performance, enzymatic activity, antioxidant response and metabolic pathway of Chlorella pyrenoidosa (C. pyrenoidosa) under different salinities have been investigated during the treatment of aquaculture wastewater. The growth, chlorophyll content and photosynthetic activity of C. pyrenoidosa were negatively correlated with the salinity from 1% to 3%. The removal performance of chemical oxygen demand (COD) and nitrogen compounds for C. pyrenoidosa decreased with the increase of salinity from 1% to 3%, which was due to the decrease of their corresponding metabolism enzymatic activities. The equilibrium between the reactive oxygen species production and antioxidant defensive system in C. pyrenoidosa was destroyed under high salinity stress and then caused an irreversible damage, which decreased the nitrogen assimilation of C. pyrenoidosa. The metabolic pathway of C. pyrenoidosa under 3% salinity had some obvious variation by comparison with 1% salinity, which led to the discrepancy in the microalgae activity and nitrogen transformation performance. Additionally, high salinity could inhibit the expression of gene associated with the chlorophyll synthesis and damaged the photosystem II reaction center. This study can provide an insight into the effect of salinity on the nitrogen removal from aquaculture wastewater by microalgae.

Synergistic Effects of Nitrogen–Oxygen–Nitrogen, Forming Gas–Oxygen–Forming Gas, and Argon–Oxygen–Argon Annealing Ambient on the Structural and Electrical Characteristics of Thulium Oxide Passivation Layers on Silicon Substrate

A comprehensive probe was conducted to compare the impact of postdeposition annealing at 700°C in different ambient of nitrogen–oxygen–nitrogen (NON), forming gas–oxygen–forming gas (FGOFG), and argon–oxygen–argon (ArOAr) on the passivating characteristics of thulium oxide (Tm2O3) on the silicon (Si) substrate. The nitrogen ions have been incorporated in Tm2O3 passivation layers after annealing in NON and FGOFG ambient, of which NON ambient has impeded the growth of silicon oxide (SiO2) interfacial layer (3.258 nm). Although a thicker SiO2 interfacial layer (4.026 nm) was formed after annealing in FGOFG ambient, the attainment of the highest k value (16.8) indicated that the existence of hydrogen ions has assisted the improvement in the overall k value of Tm2O3 passivation layers. Furthermore, the capacitance–voltage characteristic revealed that the FGOFG ambient was effective in reducing the effective oxide charge (1.32 × 1012 cm−2), while NON ambient was effective in passivating the slow trap density (STD) (3.20 × 1011 cm−2). The Terman, Hill–Coleman, and high–low frequency methods have demonstrated the acquisition of the best interface quality during annealing in FGOFG ambient. As a result, the FGOFG annealing process has led to the maximum breakdown electric field of 4.03 MV/cm and the minimum leakage current density for the Tm2O3 passivation layer.

Furazan and Furoxan—A Promising Building Block for Energetic Materials

ABSTRACTThis review summarizes the representative furazan/furoxan‐based high‐energy‐density materials (HEDMs) synthesized in recent years, the related detonation parameters, and their synthesis methods, as well as classifies them based on their engineering practicality. These materials have furazan or furoxan as the key structure, which is linked to various energetic groups or nitrogen‐rich and nitrogen–oxygen azoles, such as 1,2,4‐triazole, tetrazole, and 1,2,4‐ and 1,3,4‐oxadiazoles. The review also mentions several compounds linked by two or more furazan/furoxan rings. For compounds capable of synthesizing ionic salts, some corresponding ionic salts of energetic compounds are also presented. The majority of discussed compounds have relatively good detonation properties and high sensitivity. They also have the potential to replace existing conventional explosives, such as TNT, RDX, and HMX.