BaO2 Research Articles

Metal Peroxide Nanoparticles for Modulating the Tumor Microenvironment: Current Status and Recent Prospects.

Background: The significant expansion of nanobiotechnology and nanomedicine has led to the development of innovative and effective techniques to combat various pathogens, demonstrating promising results with fewer adverse effects. Metal peroxide nanoparticles stand out among the crucial yet often overlooked types of nanomaterials, including metals. These nanoparticles are key in producing oxygen (O2) and hydrogen peroxide (H2O2) through simple chemical reactions, which are vital in treating various diseases. These compounds play a crucial role in boosting the effectiveness of different treatment methods and also possess unique properties due to the addition of metal ions. Methods: This review discusses and analyzes some of the most common metal peroxide nanoparticles, including copper peroxide (CuO2), calcium peroxide (CaO2), magnesium peroxide (MgO2), zinc peroxide (ZnO2), barium peroxide (BaO2), and titanium peroxide (TiOx) nanosystems. These nanosystems, characterized by their greater potential and treatment efficiency, are primarily needed in nanomedicine to combat various harmful pathogens. Researchers have extensively studied the effects of these peroxides in various treatments, such as catalytic nanotherapeutics, photodynamic therapy, radiation therapy, and some combination therapies. The tumor microenvironment (TME) is particularly unique, making the impact of nanomedicine less effective or even null. The presence of high levels of reactive oxygen species (ROS), hypoxia, low pH, and high glutathione levels makes them competitive against nanomedicine. Controlling the TME is a promising approach to combating cancer. Results: Metal peroxides with low biodegradability, toxicity, and side effects could reduce their effectiveness in treating the TME. It is important to consider the distribution of metal peroxides to effectively target cancer cells while avoiding harm to nearby normal cells. As a result, modifying the surface of metal peroxides is a key strategy to enhance their delivery to the TME, thereby improving their therapeutic benefits. Conclusions: This review discussed the various aspects of the TME and the importance of modifying the surface of metal peroxides to enhance their therapeutic advantages against cancer, as well as address safety concerns. Additionally, this review covered the current challenges in translating basic research findings into clinical applications of therapies based on metal peroxide nanoparticles.

Crystal facet-dependent upgrading of saccharides over barium peroxide to synthesize C-glycoside ketones

Crystal facet-dependent Knoevenagel condensation of barium peroxide (BaO2) achieves the efficient construction of C–C bonds of unprotected saccharides to synthesize C-glycosides.

Design, synthesis and formation mechanism of a novel entropy-stabilized perovskite oxide derived from barium cerate/zirconate

Through the use of the cluster-plus-glue atom model, we theoretically designed a novel perovskite-structured oxide (ABO3), derived from a barium cerate/zirconate, with the following chemical formula: Ba(Ce0.2Zr0.2Gd0.2La0.2Y0.2)O2.7. Given the five different cations on the B-site, we demonstrated that the novel system is an Entropy-Stabilized Perovskite Oxide, which exhibits a reversible transition from a single-phase to a multiphase system. By using a simple coprecipitation process, we were able to synthesize and then sinter a well-densified single-phase perovskite. In the present work, we discussed for the first time the complex interactions occurring among the involved species that, depending on the treatment conditions, could lead to the formation of either an entropy-stabilized orthorhombic perovskite or a metastable cubic perovskite.

Pyrotechnic Delay Compositions Based on BaO2: Not as "Green" as Expected.

The aims of this study were to investigate the potential of using barium peroxide as an environmentally friendly oxidising agent, to evaluate the composition of the combustion products of the developed pyrotechnic delay compositions (PDCs) and to provide information about the impact of the utilised metallic fuel (Mg, Al, Fe or Cu) on the properties of those PDCs. The PDCs exhibited acceptable friction and impact sensitivity values. This allowed conducting further experiments, e.g., determining the linear combustion velocity of the PDCs as a function of oxygen balance (OB). Based on the composition of the post-combustion residues, determined by Raman spectroscopy and SEM-EDS, an initial mechanism for the combustion of the developed PDCs was proposed.

In-situ infrared spectroscopy analysis of proton-conducting oxy-hydroxides Ba(Zn, M)O2.9−y(OH)2y (M = Ta or W)

The bonding nature of hydroxide ions in two proton-conducting oxy-hydroxides, perovskite-type Ba(Zn0.4Ta0.6)O2.9−y(OH)2y (BZT) and double perovskite-type Ba(Zn0.55W0.45)O2.9−y(OH)2y (BZW), has been studied by Fourier transform infrared spectroscopy (FT-IR) at temperatures of 40–600 ​°C. A broad absorption peak at 2500−4000 ​cm−1 attributable to O–H stretching vibration was analyzed by deconvolution into four components, assigned as two symmetric (SC) and two asymmetric (AC) proton sites in the crystal lattice. The temperature variations of peak intensities revealed a difference in proton site preference between BZT and BZW, suggesting a crucial role of B-site cationic order in the proton distribution and, thereby, the proton conductive property.

Improved energy storage performance of Ba(Ti,Ca)O3 ceramics through tailoring phase structure and ferroelectric polarization

A novel strategy was adopted to prepare (1 − x)Ba(Ti0.97Ca0.03)O2.97–x(Bi0.51Na0.47)0.94Ba0.06TiO3 (abbreviated as (1 − x)BTC–xBNBT, x = 0.03–0.15) relaxor ferroelectric ceramics by precisely tailoring the phase structure and ferroelectric polarization. Significant enhancements in both polarization and dielectric breakdown strength are successfully achieved by realizing the phase structure dominated by the tetragonal phase in relaxor ferroelectrics. Notably, the 0.9BTC–0.1BNBT ceramic simultaneously shows an outstanding recoverable energy density of 2.17 J cm−3 and a high efficiency of 84.5% at 240 kV cm−1, as well as superior temperature (20 °C–160 °C) and frequency (1–100 Hz) stability. In addition, the charge–discharge test results show that the 0.9BTC–0.1BNBT ceramic has an ultra-fast discharge rate of t 0.9 ∼ 75 ns, an ultra-high power density of 27.7 MW cm−3 and a high discharge energy density of 0.58 J cm−3. This work not only provides a promising energy storage material for pulse capacitors, but also presents an effective method for developing new high-performance BaTiO3-based dielectric materials.

Proton conductive behaviors of Ba(ZnxNb1−x)O3−δ−y(OH)2y studied by infrared spectroscopy

Proton-conductive behaviors of oxy-hydroxide perovskites Ba(ZnxNb1−x)O3−δ−y(OH)2y (BZN) were investigated by Fourier transform infrared spectroscopy (FT-IR) at 40–600 ​°C. The in-situ FT-IR analysis upon heating in flowing N2 gas revealed a broad IR peak at about 2500–3700 ​cm−1, attributed to O–H stretching vibration modes. The broadened IR peak was deconvoluted with four Gaussian components, and their relative intensities are dependent on temperature, indicating the presence of site preference of protons in the BZN crystal lattice. The proton site preference in BZN was discussed based on the comparison of spectral features between BZN and Ba(Zr0.9Y0.1)O2.95 as a reference.

The Gallate Pnictides Ba9[GaO4]3Pn (Pn=Sb, Bi) and a Partially Oxidized Zintl Anion in Ba2[GaO2As

AbstractThe reaction of elemental barium, gallium and either bismuth or antimony with small amounts of barium peroxide yields yellow platelet‐shaped crystals of Ba9[GaO4]3Sb (1) and orange platelet‐shaped crystals of Ba9[GaO4]3Bi (2), respectively. Using arsenic instead of bismuth or antimony, black metallic shining crystals of Ba2[GaO2As] (3) are obtained. The crystals of these compounds are air‐sensitive and have been characterized by single crystal X‐ray diffraction and energy dispersive X‐ray fluorescence spectroscopy. 1 and 2 contain tetrahedral [GaO4]5− units and isolated Sb3− and Bi3− ions coordinated solely by Ba2+‐ions in icosahedral and cuboctahedral fashion. 3 is built of [GaO2As2/2]4− tetrahedra, which are linked via the As atoms to infinite chains. This polyanion can be perceived as a typical Zintl anion, which is partially oxidized.

Insight into the Effect of Moisture and Thermal Aging on the Degradation of a Pyrotechnic Igniter Composition through Thermogravimetric Kinetics Coupled with Deconvolution Approach

AbstractIn the present study, the effect of moisture and thermal aging on the degradation of a pyrotechnic igniter composition (PIC) composed of magnesium (Mg) as fuel and dual‐oxidizer of barium nitrate (Ba(NO3)2) and barium peroxide (BaO2) has been investigated to well understand the main compositional and structural changes that may occur. The unaged and aged samples were examined through non‐destructive techniques, namely, Raman and Fourier transform infrared (FTIR) spectroscopies, scanning electron microscopy (SEM), and X‐ray diffraction (XRD). The thermal decomposition behavior and the kinetic parameters of the different Mg‐PIC samples were determined using thermogravimetry (TGA) analysis coupled with a deconvolution approach. The obtained results revealed that the aging processes performed at 65 °C and 85 % relative humidity (RH), respectively, affected the chemical structure of the samples, and the degradation became more pronounced with the increase of the aging time. These changes are attributed to the partial decomposition of barium nitrate, barium peroxide, and the oxidation of magnesium, which generated Ba(NO2)2, MgO, and Mg(OH)2 as degradation products. On the other hand, based on the TGA data, the kinetic modelling was carried out through the deconvolution approach combined with isoconversional kinetic analysis to determine the multiple‐step kinetic behaviors of the different PIC samples. The results revealed that the aging processes may engender various degradation reactions with different activation energies compared to the fresh sample, what can lead to severe changes in stability and untrustworthy performance of the pyrotechnic compositions.

Influence of the Pyrotechnic Igniter Composition Aging on Explosion Parameters of Dispersed Dusts

A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a Standards to study the explosiveness of dispersed dusts. Its pyrotechnic composition consists of 1.2 g of zirconium (40% wt.), barium peroxide (30% wt.) and barium nitrate (30% wt.). The energy released during the combustion of that amount of composition is 5 kJ. The article investigates the influence of aging of the pyrotechnic composition in the igniter on its initiation parameters. In the study, igniters of different years from date of manufacture were used: Igniter 1, manufactured in 2021 (less than 1 year from date of manufacture), and Igniter 2 (more than 2 years from date of manufacture). The study was performed in the KV 150M2 explosion chamber with a volume of 365 L and the 20 L sphere chamber with a volume of 20 L. A standard sample of Lycopodium clavatum was used in the KV 150M2 explosion chamber. Magnesium and benzoic acid were used as the samples in the 20 L sphere explosion chamber. The experiment showed that the explosion pressure Pmax of the igniter with more than 2 years from date of manufacture decreased by up to 10%, while the value of the explosion constant Kst decreased by up to 40%. The attained results proved that aging of igniters affects their explosion parameters and measurement accuracy.

Oxidation processes at the surface of BaTiO3 thin films under environmental conditions

Dissociation and adsorption of water on ferroelectric oxide surfaces playimportant role in the processes of screening and switching dynamics of ferroelectric polarization, as well as in catalytic processes which can be additionally coupled with light, temperature or vibration stimuli. In this work,we present XPS study of ferroelectric BaTiO3thin films and determine the entanglement between surface chemistry, polarization direction and stability, by observing changes upon time exposure to environmental conditions, heating in O2atmosphereandirradiation in vacuum. We devote special attention to Ba 3d spectral region and identify two different oxidation states of O atoms in the compounds of Ba. While this second specie was generally attributed to Ba in surface compounds where it has different oxygen coordination than in the bulk, based on the XPS results of oxygen annealed thin films,we demonstrate that this so far neglected component, corresponds to barium peroxide (BaO2)and identify it as important active specie for the study of screening mechanisms closely related with catalytic activity present in this ferroelectric material. Finally, we report on chemically assisted polarization switching in thin films induced byheating in vacuum or exposure to X-Ray radiation due to the formation of positive surface electric field created by oxygen orelectron vacancies, respectively.

Chemoreactive Nanotherapeutics by Metal Peroxide Based Nanomedicine.

The advances of nanobiotechnology and nanomedicine enable the triggering of in situ chemical reactions in disease microenvironment for achieving disease‐specific nanotherapeutics with both intriguing therapeutic efficacy and mitigated side effects. Metal peroxide based nanoparticles, as one of the important but generally ignored categories of metal‐involved nanosystems, can function as the solid precursors to produce oxygen (O2) and hydrogen peroxide (H2O2) through simple chemical reactions, both of which are the important chemical species for enhancing the therapeutic outcome of versatile modalities, accompanied with the unique bioactivity of metal ion based components. This progress report summarizes and discusses the most representative paradigms of metal peroxides in chemoreactive nanomedicine, including copper peroxide (CuO2), calcium peroxide (CaO2), magnesium peroxide (MgO2), zinc peroxide (ZnO2), barium peroxide (BaO2), and titanium peroxide (TiOx) nanosystems. Their reactions and corresponding products have been broadly explored in versatile disease treatments, including catalytic nanotherapeutics, photodynamic therapy, radiation therapy, antibacterial infection, tissue regeneration, and some synergistically therapeutic applications. This progress report particularly focuses on the underlying reaction mechanisms on enhancing the therapeutic efficacy of these modalities, accompanied with the discussion on their biological effects and biosafety. The existing gap between fundamental research and clinical translation of these metal peroxide based nanotherapeutic technologies is finally discussed in depth.

Fecal blood tests-screening methods for identification of pre-tumor changes and tumors at the early stage

Mortality due to cancer of the rectal colon is currently increasing in all groups of the adult population. Various screening methods are used to identify the pre-tumor and early stages of the development of tumor pathology of the colon: occult blood tests in feces, computer colonography (virtual colonoscopy), colonoscopy, DNA testing, tumor marker M2-PK (tumor fractional pyruvate kinase fraction M2). All of these colorectal cancer screening methods give good results, but there is no consensus among experts regarding the choice of the most optimal method. One of the first tests to detect hidden blood in the stool was biochemical tests: guaiac test (gFOBT guaiac fecal occult-blood test ), in which hemoglobin in the stool was detected by a biochemical method that exploited the pseudoperoxidase activity of hemoglobin and the Gregersen reaction, which is a benzidine test in which benzidi was used instead of guaiac resin And instead of a hydrogen peroxide barium peroxide. Enzyme-linked immunosorbent assays, in contrast to biochemical ones, use antibodies specific only to human hemoglobin, which excludes false-positive results obtained using the biochemical method. The FIT test (Fecal Immunochemical Test or Immunochemical Fecal occult blood test) specifically determines human hemoglobin in feces at lower threshold values (40300 g HB/1 g feces) compared to g-FOBT. Due to its high accuracy, Enzyme-linked immunosorbent assays are successfully used to detect occult blood in inflammatory bowel diseases, allergic enteropathies, acute intestinal infections, and erosive gastritis.

Effect of NH4F treatment on the chromaticity of the Ba2+-doped γ-Ce2S3 red pigment

The Ba2+-doped cerium precursor powder, (Ce, Ba)CO3, was successfully prepared via a co-precipitation reaction method using Ce(NO3)3·6H2O, Ba(NO3)3, and (NH4)2CO3 as raw materials. The above powder was placed in a muffle furnace and calcined at 1000°C for 120 min to obtain the corresponding oxide, (Ce, Ba)O2, subsequently, and the oxide was vulcanized at 850°C for 150 min with CS2 as a sulfur source to obtain the Ba2+-doped γ-Ce2S3 red pigment. The effects of different NH4F concentrations (1.0, 2.5, and 4.0 M) and treatment times (30, 60, 90, and 120 min) on the phase composition and chromaticity of the pigment were studied by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffractometry (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and CIELAB colorimetry. The SEM and EDS analyses revealed the presence of irregular flaky particles on the pigment surface after the NH4F treatment; the amounts of particles gradually increased with the NH4F concentration. The XRD and Raman spectra confirmed that these particles were CeF3 and CeFS heterophases. Furthermore, the Raman spectra denoted the presence of amorphous carbon. The XPS analysis demonstrated that the NH4F treatment did not change the valence of Ce (Ce3+ for γ-Ce2S3). The chromaticity of a sample reached its maximum (L* = 34.24, a* = 38.19, and b* = 39.95) after it was treated using 2.5 M NH4F for 60 min, indicating that the elimination of amorphous carbon can effectively improve the pigment chromaticity.

Effect of phase transition on electrocaloric effect in Indium substituted BaTiO3 ceramics

In the present work the dense Ba(Ti1-xInx)O3-x/2 ceramics were prepared through a standard solid-state sintering method. Although only a tetragonal phase is detected by the X-ray diffraction in these ceramics, the coexistence of multiphase is observed by the selected area electron diffraction in two substituted ceramics. Moreover, the diffused phase transition is induced by the substitution, and this can be linked to the coexistence of multiphase in these ceramics. The maximal pyroelectric coefficient of Ba(Ti0.99In0.01)O2.995 ceramics is obviously larger than those of the other ceramics, which occurs beside the ferroelectric-ferroelectric transition. While the maximal pyroelectric coefficients of other ceramics locate beside the paraelectric-ferroelectric transition. Ba(Ti0.99In0.01)O2.995 ceramics show the largest adiabatic temperature change of 0.54 K and isothermal entropy change of 0.94 J/kg·K under an electric field of 30 kV/cm among all ceramics, and the largest electrocaloric effect strengths of 0.22 × 10−6 K m/V and 0.39 × 10−6 J m/kg·K·V under an electric field of 10 kV/cm are also obtained in this ceramic. For individual composition, the electrocaloric strength displays different tendencies, which can be linked to the diffusivity of the phase transition. From the present work, the relationship between electrocaloric effect and ferroelectric phase transition is revealed.

Hole‐Boosted Cu(Cr,M)O2 Nanocrystals for All‐Inorganic CsPbBr3 Perovskite Solar Cells

The all-inorganic CsPbBr3 perovskite solar cell (PSC) is a promising solution to balance the high efficiency and poor stability of state-of-the-art organic-inorganic PSCs. Setting inorganic hole-transporting layers at the perovskite/electrode interface decreases charge carrier recombination without sacrificing superiority in air. Now, M-substituted, p-type inorganic Cu(Cr,M)O2 (M=Ba2+ , Ca2+ , or Ni2+ ) nanocrystals with enhanced hole-transporting characteristics by increasing interstitial oxygen effectively extract holes from perovskite. The all-inorganic CsPbBr3 PSC with a device structure of FTO/c-TiO2 /m-TiO2 /CsPbBr3 /Cu(Cr,M)O2 /carbon achieves an efficiency up to 10.18 % and it increases to 10.79 % by doping Sm3+ ions into perovskite halide, which is much higher than 7.39 % for the hole-free device. The unencapsulated Cu(Cr,Ba)O2 -based PSC presents a remarkable stability in air in either 80 % humidity over 60 days or 80 °C conditions over 40 days or light illumination for 7 days.

Study of gasless compositions used in time-delay elements

This article presents the results of burn rate measurements conducted for a Fe/BaO2 pyrotechnic delay composition. Compositions with an iron content between 15% (w/w) and 50% (w/w) yielded burn rates in the range of 4–36 mm s−1. Mixtures containing more than 50% (w/w) iron could not be initiated by a powder fuse and are not suited for application as delay compositions. This study also presents a cost-efficient method for measuring linear combustion velocities and its application to the investigation of the Fe/BaO2 composition. Thermogravimetric and XRD studies have revealed that the reactions between iron and barium peroxide take place in the solid phase, leading to the formation of varied spinels.

Multi-functional perovskites \u2013 an investigation of compositional and processing influence on microstructure, dielectric and ferroelectric properties

Ba(Ni0.5Nb0.5)O2.75 (BNNO) doped KNbO3 (KN) and (K0.5Na0.5)NbO3 (KNN), abbreviated as KBNNO and KNBNNO, respectively, have been recently reported to co-exhibit narrow band gaps (visible range) and strong piezoelectric/pyroelectric effects simultaneously within the same material. This had never been achieved in a single ceramic material. Such a breakthrough may allure the development of fundamentally novel multi-source energy harvesters based on only one piece of material as well as advanced optoelectronic devices with multiple functions. It has been found that the window of getting the unique combination of these properties is very narrow. Even a slight shifting away from the stoichiometry of the compositions may induce a significant loss of the properties. The reasons are expected to be in the compositions and microstructure of these materials. However, detailed information – e.g. the correlation of the compositions, processing conditions, microstructure and properties – remains to be investigated for such novel materials. In this paper, the inter-influence of different doping amounts of BNNO, calcination and sintering temperatures, phase structures and defects (potassium loss and oxygen vacancy) on the dielectric and ferroelectric properties are studied. The paper reveals the principles and provides guidance to achieving good ferroelectric properties in these emerging perovskite structured materials.

Infrared‐to‐ultraviolet light‐absorbing BaTiO3‐based ferroelectric photovoltaic materials

AbstractFerroelectric oxides have been demonstrated to be promising in developing emerging photovoltaic technologies because of the various mechanisms that allow above‐band‐gap photovoltages and higher efficiencies. However, the wide band gaps of conventional ferroelectric oxides (2.7‐4 eV) limit their utilization of the solar spectrum. Here the phase stability, absorption properties, ferroelectric, and photovoltaic responses of Ni‐ and Ni‐Nb‐substituted BaTiO3 were explored to evaluate their potential as visible‐light‐absorbing photovoltaic materials. Although the acceptor substitution of Ni2+ stabilized a hexagonal 6H polymorph in both systems, post‐annealing treatments allowed restoration of a tetragonal 3C phase for Ba(Ti0.99Ni0.01)O2.99 and (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75. The oxygen vacancies accompanying the Ni and Ni‐Nb substitutions significantly lower the optical band gap of BaTiO3 to ~1.5 eV and the visible light absorption can be systematically tuned between 380 and 1000 nm by varying the Ni:Nb ratio. Room temperature ferroelectricity was observed in Ba(Ti0.99Ni0.01)O2.99 with a saturation polarization = 18 μC/cm2 and remnant polarization = 1 μC/cm2. The Ni‐Nb substituted composition (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75 shows a ferroelectric response with a remnant polarization of 5 μC/cm2 at 77 K, which gradually decreases as temperature increases. Both compositions exhibit ferroelectrically switchable photoresponses under an AM 1.5 G sunlight simulator; the highest switchable steady‐state current of 8 nA/cm2 observed for (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75 exceeds those reported in previous studies of BaTiO3 ceramic samples (J Solid State Chem, 1975; 12: 193; Jpn J Appl Phys, 2013; 52: 09KF03).

Recent progress on electrochemical production of hydrogen peroxide

Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic esters. Anthraquinone process (an old production process of H2O2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H2O2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O2 is cathodically reduced to produce H2O2 via 2-electron pathway or 4-electron pathway to get H2O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H2O2. In this review paper, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives such as, anthraquinone method for industrial H2O2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H2O2. From revision of experimental and theoretical data from the past literature; we argue that successful implementation of electrochemical H2O2 production can be realized on the basis of stable, active and selective catalyst.