Peroxide Molecules Research Articles

Study of the Use of Oxygenated Water as a Non-Toxic Molecule Model for Catalytic Testing of Pozzolana-PN and Iron-Based NOx Reducing Catalysts

During previous catalytic tests on the reducing power of NOx catalysts based on pozzolana and PN-black citric acid polymer, it was found that the use of the NO<sub>2</sub> model molecule poses a significant health and environmental risk. Thus, a project was launched to find another, much less harmful model molecule. Hydrogen peroxide H<sub>2</sub>O<sub>2</sub> was chosen, a molecule naturally secreted by the body to prevent pigment synthesis, with disinfectant, antiseptic and whitening properties widely used in various activities, including cosmetics. Consequently, catalytic tests of NOx-reducing power using hydrogen peroxide H<sub>2</sub>O<sub>2</sub> as a model molecule were carried out on two catalysts based on pozzolana and PN-black polymer of citric acid, PNP-Fe-water-15% and PNP-Fe-ethanol-15%, differing in the solvent used during their syntheses according to a procedure detailed in the bibliography and this manuscript. Pozzolana is a volcanic rock widespread in the volcanic mountains in the Vakinankaratra region of Madagascar. Its use as a support for catalysts based on PN-black polymer of citric acid and Iron-Fe enabled us to synthesize various catalysts, the characteristics and synthesis methods of which are detailed in this manuscript. In short, the catalytic test with hydrogen peroxide was conclusive, enabling a pragmatic comparison of the two catalysts tested, with the result that the catalyst synthesized with water PNP-Fe-water-15% is more active than the catalyst synthesized with ethanol PNP-Fe-ethanol-15%. This is due to the quality and difference in dispersion of the PN-black polymer molecules depending on the solvent used, which can have an impact on the nature of the catalyst surfaces and certain characteristics such as porosity. This dispersion is confirmed and viewed using an optical microscope to visualize the surface of a catalyst grain. Kinetic results from two proposed mechanisms for the reduction of H<sub>2</sub>O<sub>2</sub> hydrogen peroxide molecules using PNP-Fe catalysts also confirmed not only the proposed mechanisms, but also the higher activity of PNP-Fe catalysts synthesized with water, whose kinetic constants are much higher than those synthesized with ethanol.

S-Equol Ameliorates Menopausal Osteoarthritis in Rats through Reducing Oxidative Stress and Cartilage Degradation.

Osteoarthritis (OA) is a chronic degenerative disease leading to articular cartilage destruction. Menopausal and postmenopausal women are susceptible to both OA and osteoporosis. S-equol, a soy isoflavone-derived molecule, is known to reduce osteoporosis in estrogen-deficient mice, but its role in OA remains unknown. This study aimed to explore the effect of S-equol on different degrees of menopausal OA in female Sprague-Dawley (SD) rats induced by estrogen deficiency caused by bilateral ovariectomy (OVX) combined with intra-articular injection of mono-iodoacetate (MIA). Knee joint histopathological change; serum biomarkers of bone turnover, including N-terminal propeptide of type I procollagen (PINP), C-terminal telopeptide of type I collagen (CTX-I) and N-terminal telopeptide of type I collagen (NTX-I); the cartilage degradation biomarkers hyaluronic acid (HA) and N-terminal propeptide of type II procollagen (PIINP); and the matrix-degrading enzymes matrix metalloproteinases (MMP)-1, MMP-3 and MMP-13, as well as the oxidative stress-inducing molecules nitric oxide (NO) and hydrogen peroxide (H2O2), were assessed for evaluation of OA progression after S-equol supplementation for 8 weeks. The results showed that OVX without or with MIA injection induced various severity levels of menopausal OA by increasing pathological damage, oxidative stress, and cartilage matrix degradation to various degrees. Moreover, S-equol supplementation could significantly reduce these increased biomarkers in different severity levels of OA. This indicates that S-equol can lessen menopausal OA progression by reducing oxidative stress and the matrix-degrading enzymes involved in cartilage degradation.

The role of strigolactones in resistance to environmental stress in plants.

Abiotic stress impairs plant growth and development, thereby causing low yield and inferior quality of crops. Increasing studies reported that strigolactones (SL) are plant hormones that enhance plant stress resistance by regulating plant physiological processes and gene expressions. In this review, we introduce the response and regulatory role of SL in salt, drought, light, heat, cold and cadmium stresses in plants. This review also discusses how SL alleviate the damage of abiotic stress in plants, furthermore, introducing the mechanisms of SL enhancing plant stress resistance at the genetic level. Under abiotic stress, the exogenous SL analog GR24 can induce the biosynthesis of SL in plants, and endogenous SL can alleviate the damage caused by abiotic stress. SL enhanced the stress resistance of plants by protecting photosynthesis, enhancing the antioxidant capacity of plants and promoting the symbiosis between plants and arbuscular mycorrhiza (AM). SL interact with abscisic acid (ABA), salicylic acid (SA), auxin, cytokinin (CK), jasmonic acid (JA), hydrogen peroxide (H2O2) and other signal molecules to jointly regulate plant stress resistance. Lastly, both the importance of SL and their challenges for future work are outlined in order to further elucidate the specific mechanisms underlying the roles of SL in plant responses to abiotic stress.

SWEET family transporters act as water conducting carrier proteins in plants.

Dedicated water channels are involved in the facilitated diffusion of water molecules across the cell membrane in plants. Transporter proteins are also known to transport water molecules along with substrates, however the molecular mechanism of water permeation is not well understood in plant transporters. Here, we show plant sugar transporters from the SWEET (Sugar Will Eventually be Exported Transporter) family act as water-conducting carrier proteins via a variety of passive and active mechanisms that allow diffusion of water molecules from one side of the membrane to the other. This study provides a molecular perspective on how plant membrane transporters act as water carrier proteins, a topic that has not been extensively explored in literature. Water permeation in membrane transporters could occur via four distinct mechanisms which form our hypothesis for water transport in SWEETs. These hypothesis are tested using molecular dynamics simulations of the outward-facing, occluded, and inward-facing state of AtSWEET1 to identify the water permeation pathways and the flux associated with them. The hydrophobic gates at the center of the transport tunnel act as a barrier that restricts water permeation. We have performed in silico single and double mutations of the hydrophobic gate residues to examine the changes in the water conductivity. Surprisingly, the double mutant allows the water permeation to the intracellular half of the membrane and forms a continuous water channel. These computational results are validated by experimentally examining the transport of hydrogen peroxide molecules by the AtSWEET family of transporters. We have also shown that the transport of hydrogen peroxide follows the similar mechanism as water transport in AtSWEET1. Finally, we conclude that similar water-conduction states are also present in other SWEET transporters due to the high sequence and structure conservation exhibited by this transporter family.

Theoretical studies the structure and properties of bicyclic and tricyclic hydrogen peroxide clusters (H2O2)n, n = 8–21: MP2 and DFT calculations

DFT calculations of bicyclic and tricyclic hydrogen peroxide (HP) clusters Pn up to n = 21 in the gas phase have been performed for the first time. Three main types of coupling of two or more ring clusters P4-P7 (tetramer, pentamer, hexamer, heptamer) into a cyclic structure have been studied. The first, type A, involves the reorientation of hydrogen bonds and a change in the chirality of several HP molecules. The second, type B, consists in the formation of bridges between two HP molecules without changing the chirality. The third way in which two clusters can be connected is by forming nested structures in which the smaller cluster is inside the larger one. Thermodynamic parameters of the coupling of P4-P7 clusters with the formation of cyclic structures have been calculated. In the gas phase, heterochiral structures of type A are lower in energy than homochiral structures of type B with the same number of HP molecules. In low energy clusters, the largest number of hydrogen bonds (2n) is more favourable.

The rational of a fixed combination of benzoyl peroxide and niacinamide in the treatment of acne vulgaris: A narrative review

Acne vulgaris (AV) in a common skin disease affecting mainly adolescents but could be present also in adult subjects. AV is characterized by the presence of non-inflammatory (comedons) and inflammatory (papules, pustules, cysts, and nodules) lesions affecting sebaceous glands rich regions like the face, back, shoulder and thorax. A central pathogenetic role of AV lesions seems played by Cutibacterium acnes, especially some phylotypes (i.e. C. acne IA1) able to induce an inflammatory response at the level of sebaceous glands. Other important pathogenetic factors of AV are the adrogen-driven increase of sebum production and the process of hyperkeratinisation of the infundibulum. The first line treatment of AV is in general done using monotherapy with antibacterial agents like benzoyl peroxide (BPO) and hydrogen peroxide or topical retinoid molecules. These two classes of drugs could interfere with C. acnes growth (BPO) and with keratinocytes proliferation (retinoid). Fixed combination of BPO and retinoid molecules are commonly used in mild to moderate forms of AV. However, both BPO and retinoids could be nor well tolerated especially during the first weeks of treatment causing skin irritation erythema and and dryness. Both BPO and topical retinoids could interfere with the skin barrier function. During BPO treatment the Trans epidermal water loss (TEWL) a marker of skin barrier function, increase significantly supporting the fact that BPO alters this function. Niacinamide is a potent anti-inflammatory molecule able to preserve the skin barrier function. Niacinamide has shown to be effective in AV with inflammatory lesions. There is a strong rationale for the development of a topical product formed by fixed combination of BPO and niacinamide for the first-line treatment of mild to moderate AV but also in the treatment of papulopustular rosacea. In this narrative review we discuss the rational of the combination and the first clinical data of this product as first line AV and rosacea treatment strategy.

A Review Of Certain Medical Plants With Antioxidant Qualities And In Vitro Approaches For Measuring Antioxidant Activity

Reactive oxygen species (ROS) are a type of extremely reactive molecule that results from oxygen metabolism. ROS, which include superoxide radicals, hydroxyl radicals, and hydrogen peroxide molecules, are frequently produced as byproducts of biological reactions or as a result of external causes. There is substantial evidence that ROS play a role in the development of degenerative illnesses. Evidence suggests that chemicals, particularly those derived from natural sources, can provide free radical protection. This has piqued the curiosity of researchers in natural antioxidants. Screening medicinal plants for antioxidant capacity is required. As a result, an attempt was undertaken to analyze various in vitro methods for assessing antioxidant activities of natural compounds derived from medicinal plants. All of the models are detailed, as well as the various estimation criteria. Finally, a great number of plants with antioxidant activity in vitro are described, although in vivo research is sparse.

Substrate-dependent oxidative inactivation of a W-dependent formate dehydrogenase involving selenocysteine displacement.

Metal-dependent formate dehydrogenases are very promising targets for enzyme optimization and design of bio-inspired catalysts for CO2 reduction, towards innovative strategies for climate change mitigation. For effective application of these enzymes, the catalytic mechanism must be better understood, and the molecular determinants clarified. Despite numerous studies, several doubts persist, namely regarding the role played by the possible dissociation of the SeCys ligand from the Mo/W active site. Additionally, the oxygen sensitivity of these enzymes must also be understood as it poses an important obstacle for biotechnological applications. This work presents a combined biochemical, spectroscopic, and structural characterization of Desulfovibrio vulgaris FdhAB (DvFdhAB) when exposed to oxygen in the presence of a substrate (formate or CO2). This study reveals that O2 inactivation is promoted by the presence of either substrate and involves forming a different species in the active site, captured in the crystal structures, where the SeCys ligand is displaced from tungsten coordination and replaced by a dioxygen or peroxide molecule. This form was reproducibly obtained and supports the conclusion that, although W-DvFdhAB can catalyse the oxidation of formate in the presence of oxygen for some minutes, it gets irreversibly inactivated after prolonged O2 exposure in the presence of either substrate.

Implementing vanadium peroxides as direct air carbon capture materials.

Direct air capture (DAC) removal of anthropogenic CO2 from the atmosphere is imperative to slow the catastrophic effects of global climate change. Numerous materials are being investigated, including various alkaline inorganic metal oxides that form carbonates via DAC. Here we explore metastable early d0 transition metal peroxide molecules that undergo stabilization via multiple routes, including DAC. Specifically here, we describe via experiment and computation the mechanistic conversion of A3V(O2)4 (tetraperoxovanadate, A = K, Rb, Cs) to first a monocarbonate VO(O2)2(CO3)3-, and ultimately HKCO3 plus KVO4. Single crystal X-ray structures of rubidium and cesium tetraperoxovanadate are reported here for the first time, likely prior-challenged by instability. Infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), 51V solid state NMR (nuclear magnetic resonance), tandem thermogravimetry-mass spectrometry (TGA-MS) along with calculations (DFT, density functional theory) all converge on mechanisms of CO2 capture and release that involve the vanadium centre, despite the end product of a 300 days study being bicarbonate and metavanadate. Electron Paramagnetic Resonance (EPR) Spectroscopy along with a wet chemical assay and computational studies evidence the presense of ∼5% adventitous superoxide, likely formed by peroxide reduction of vanadium, which also stabilizes via the reaction with CO2. The alkalis have a profound effect on the stability of the peroxovanadate compounds, stability trending K > Rb > Cs. While this translates to more rapid CO2 capture with heavier alkalis, it does not necessarily lead to capture of more CO2. All compounds capture approximately two equivalents CO2 per vanadium centre. We cannot yet explain the reactivity trend of the alkali peroxovanadates, because any change in speciation of the alkalis from reactions to product is not quantifiable. This study sets the stage for understanding and implementing transition metal peroxide species, including peroxide-functionalized metal oxides, for DAC.

Nanozymatic degradation and simultaneous colorimetric detection of tetracycline.

Tetracycline (TC) is a broad-spectrum antibiotic that can enter and accumulate in the human body via the food chain. Even in small concentrations, TC can cause several malignant health effects. We developed a system to simultaneously degrade the presence of TC in food matrices using titanium carbide MXene (FL-Ti3C2Tx). The FL-Ti3C2Tx exhibited biocatalytic property that activates hydrogen peroxide (H2O2) molecules in 3, 3', 5, 5'-tetramethylbenzidine (TMB environment. During the FL-Ti3C2Tx reaction, the catalytic products released turn the color of the H2O2/TMB system bluish-green. However, when TC is present, the bluish-green color does not appear. Via quadrupole time-of-flight mass spectrometry, we found that the TC is degraded by FL-Ti3C2Tx / H2O2 in preference to H2O2/TMB redox reaction, which intervenes in the color change. Hence, we developed a colorimetric assay to detect TC with a LOD of 615.38nM and proposed two TC degradation pathways that facilitate the highly sensitive colorimetric bioassay.

Mesoporous SiO2 anode armour for lithium oxygen battery

We are reporting a new lithium (Li) anode protective strategy using mesoporous silicon dioxide (mSiO2) to extend the operation lifetime for Li oxygen batteries (LOBs). The fabrication method is simple and easy for mass production. The mSiO2 protective layer inhibits the growth of Li dendrites and prevents the intrinsic Li corrosion phenomenon that occurs in all Li-metal-based batteries during charge/discharge cycles, the porous structure of nanoparticles within the mSiO2 also actively created parallel pathways for Li+ transport thus enhancing the mass transfer. Propylene carbonate/Li with a 100 μL drop amount of mSiO2 protective layer (mPL100) showed excellent per-formance in the Li||Li battery charge/discharge cycle test, withstanding 2,276 h of continuous operation, almost 16 times longer than the battery without the protective layer, and the LOB charge/discharge cycle test with the mSiO2 protective layer reached 382 cycles, another significant increase of 6.2 times over the unprotected battery, the full discharge capacity also reached 56,902 mAh/g that is nearly 19 times higher than the unprotected cell. Because the mSiO2 made Li+ flux more homogeneous meanwhile promoting the uniform distribution of positive electrode products and accelerating their decomposition, thus the overpotential is reduced. This layer also blocked any H2O and peroxide molecules which attack the Li anode, therefore the retention of Li has been kept at a satisfactory level.

Novel metal peroxide nanoboxes restrain Clostridioides difficile infection beyond the bactericidal and sporicidal activity.

Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl- and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag-Au peroxide coat covering Au shell and AgCl core (AgAu-based nanoboxes). The AgAu-based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30-45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au-enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide-derived AgAu-based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.

A green edge-hosted zinc single-site heterogeneous catalyst for superior Fenton-like activity

Developing green heterogeneous catalysts with excellent Fenton-like activity is critical for water remediation technologies. However, current catalysts often rely on toxic transitional metals, and their catalytic performance is far from satisfactory as alternatives of homogeneous Fenton-like catalysts. In this study, a green catalyst based on Zn single-atom was prepared in an ammonium atmosphere using ZIF-8 as a precursor. Multiple characterization analyses provided evidence that abundant intrinsic defects due to the edge sites were created, leading to the formation of a thermally stable edge-hosted Zn-N4 single-atom catalyst (ZnN4-Edge). Density functional theory calculations revealed that the edge sites equipped the single-atom Zn with a super catalytic performance, which not only promoted decomposition of peroxide molecule (HSO5-) but also greatly lowered the activation barrier for •OH generation. Consequently, the as-prepared ZnN4-Edge exhibited extremely high Fenton-like performance in oxidation and mineralization of phenol as a representative organic contaminant in a wide range of pH, realizing its quick detoxification. The atom-utilization efficiency of the ZnN4-Edge was ~104 higher than an equivalent amount of the control sample without edge sites (ZnN4), and the turnover frequency was ~103 times of the typical benchmark of homogeneous catalyst (Co2+). This study opens up a revolutionary way to rationally design and optimize heterogeneous catalysts to homogeneous catalytic performance for Fenton-like application.

Experimental and theoretical studies of the mechanism of oxidation of arsenopyrite in the presence of hydrogen peroxide

Arsenopyrite, which is a typical gold-bearing mineral, is widely distributed in gold tailings. In this study, we have examined the surface morphology of arsenopyrite before and after oxidation, the types of oxidation products, and the oxidation mechanism. We have carried out froth flotation and contact angle measurements and found that the wettability, which is a descriptor of the hydrophilicity of the arsenopyrite surfaces, increases with the levels of surface oxidation. X-ray photoelectron spectroscopy (XPS) was used to analyze the elemental composition before and after oxidation, which has demonstrated that both Fe(II) and As(III) oxidize to Fe(III) and As(V), respectively. The microscopic changes of the surface at the atomic level were also examined by atomic force microscopy (AFM), which indicated that the oxidation products gradually and partially cover the surface of the arsenopyrite upon reaction with hydrogen peroxide. These observations explain why the arsenopyrite XPS signal and the uniform change in wettability do not vanish completely during oxidation. Finally, density functional theory (DFT) calculations were used to describe the oxidation of the surface As atoms by the O of the chemisorbed hydrogen peroxide molecules. The computational results also show that the hydrogen peroxide dissociates into two hydroxyl groups that coordinate the Fe and As atoms on the surface of the arsenopyrite. The results of this study have important implications for the reuse of gold tailings containing arsenopyrite.

Complexes of hydrogen peroxide molecules with DNA nucleic bases

The analysis of complexes formation of hydrogen peroxide molecule with DNA nucleic bases is carried out using methods of quantum chemistry. Optimized geometries of complexes are determined and the interaction energies that lead to complex formation are calculated. Comparison with the same calculations for water molecule is made. It is shown that complexes with hydrogen peroxide molecule are energetically more stable than the same complexes with water molecule. Such energetic advantage is achieved particularly due to geometrical properties of hydrogen peroxide molecule, especially presence of dihedral angle. Position of hydrogen peroxide molecule in close vicinity to DNA could lead to blocking of its recognition by proteins or direct damage via hydroxyl radical formation. These results can have significant impact in understanding of mechanisms of cancer therapy. Communicated by Ramaswamy H. Sarma

Assessment of calcium hypochlorite for Bacillus anthracis spore surface's decontamination

Contamination with microorganisms occurs in laboratories but is also of high concern in the context of bioterrorism. Decontamination is a cornerstone that promotes good laboratory practices and occupational health and safety. Among the most resistant structures formed by microorganisms are spores, produced notably by Clostridium and Bacillus species. Here, we compared six products containing four different molecules (hydrogen peroxide, peracetic acid, sodium and calcium hypochlorite) on B. anthracis Sterne spores. We first selected the most efficient product based on its activity against spore suspensions using French and European standards. Four products showed sporicidal activity, of which only two did so in a time frame consistent with good laboratory practices. Then, we tested one of these two products under laboratory conditions on fully virulent B. anthracis spores, during common use and after contamination through a spill of a highly concentrated spore suspension. We, thus, robustly validated a decontaminant based on calcium hypochlorite not only on its ability to kill spores but also on its effectiveness under laboratory conditions. At the end, we were able to assure a complete disinfection in 1 min after spillover and in 2 min for common use.

Extraction, phytochemical screening and antioxidant potential of extract of Eulophia herbacea

A family of extremely reactive molecules called reactive oxygen species (ROS) are produced during the metabolism of oxygen. Superoxide radicals, hydroxyl radicals, and hydrogen peroxide molecules are among the ROS that are frequently produced as byproducts of biological processes or as a result of external stimuli. There are several there is evidence that ROS play a role in the emergence of degenerative illnesses. There is evidence that substances, particularly those derived from natural sources, can protect against free radicals. Traditional medicines with therapeutic utility have been used since antiquity and are still contributing a significant role in the primary health-care system. Thus this article focused on the extraction, phytochemical and detection of antioxidant potential of Eulophia herbacea plant extract. The phytochemical screening revealed that the plant is a rich source of different secondary metabolites like flavonoids, saponins, carbohydrates, proteins phenol, glycosides, diterpenes and tannins. The extract only has flavonoid content with value 0.385 mg/100 mg of dried extract. The total phenolic content is only estimated in hydroalcoholic extract of Eulophia herbacea which is found to be 0.674mg/100mg of dried extract. The anti-oxidant activity was performed using DPPH method. The percentage inhibition seen to be highest this is 79.63% at maximum concentration of 100µg/ml. Beyond that IC50 value calculations reveal that Eulophia herbacea extract have comparable antioxidant potential with IC50 value for ascorbic acid is 18.69 and for plant extract it is 107.42.

Simultaneous Sensing of H2 O, D2 O and HOD through Peroxo Vibrations.

Detection of HOD simultaneously in the presence of a mixture of H2 O and D2 O is still an experimental challenge. Till date, there is no literature report of simultaneous detection of H2 O, D2 O and HOD based on vibrational spectra. Herein we report simultaneous quantitative detection of H2 O, D2 O and HOD in the same reaction mixture with the help of bridged polynuclear peroxo complex in absence and presence of Au nanoparticles on the basis of a peroxide vibrational mode in resonance Raman and surface enhanced resonance Raman spectrum. We synthesize bridged polynuclear peroxo complex in different solvent mixture of H2 O and D2 O. Due to the formation of different nature of hydrogen bonding between peroxide and solvent molecules (H2 O, D2 O and HOD), vibrational frequency of peroxo bond is significantly affected. Mixtures of different H2 O and D2 O concentrations produce different HOD concentrations and that lead to different intensities of peaks positioned at 897, 823 and 867 cm-1 indicating H2 O, D2 O and HOD, respectively. The lowest detection limits (LODs) were 0.028 mole fraction of D2 O in H2 O and 0.046 mole faction of H2 O in D2 O. In addition, for the first time the results revealed that the cis-peroxide forms two hydrogen bonds with solvent molecules.

The Boundary between Two Modes of Gas Evolution: Oscillatory (H2 and O2) and Conventional Redox (O2 Only), in the Hydrocarbon/H2O2/Cu(II)/CH3CN System

During the oxidation of hydrocarbons using hydrogen peroxide solutions, the evolution of gaseous oxygen is a side and undesirable process, in which the consumption of the oxidizer is not associated with the formation of target products. Therefore, no attention is paid to the systematic study of the chemical composition of the gas and the mechanisms of its formation. Filling this gap, the authors discovered a number of new, previously unidentified, interesting facts concerning both gas evolution and the oxidation of hydrocarbons. In a 33% H2O2/Cu2Cl4·2DMG/CH3CN system, where DMG is dimethylglyoxime (Butane-2,3-dione dioxime), and is at 50 °C, evidence of significant evolution of gaseous hydrogen, along with the evolution of gaseous oxygen was found. In the authors’ opinion, which requires additional verification, the ratio of gaseous hydrogen and oxygen in the discussed catalytic system can reach up to 1:1. The conditions in which only gaseous oxygen is formed are selected. Using a number of oxidizable hydrocarbons with the first adiabatic ionization potentials (AIPs) of a wide range of values, it was found that the first stage of such a process of evolving only gaseous oxygen was the single electron transfer from hydrogen peroxide molecules to trinuclear copper clusters with the formation, respectively, of hydrogen peroxide radical cations H2O2•+ and radical anions Cu3Cl5•− (AIP = 5 eV). When the conditions for the implementation of such a single electron transfer mechanism are exhausted, the channel of decomposition of hydrogen peroxide molecules into gaseous hydrogen and oxygen is switched on, which is accompanied by the transition of the system to an oscillatory mode of gas evolution. In some cases, the formation of additional amounts of gaseous products is provided by the catalytically activated decomposition of water molecules into hydrogen and oxygen after the complete consumption of hydrogen peroxide molecules in the reaction of gaseous oxygen evolution. The adiabatic electron affinity of various forms of copper molecules involved in chemical processes is calculated by the density functional theory method.

In-situ One-Pot Novel Synthesis of Molybdenum di-Telluride@Carbon Nano-Dots for Sensitive and Selective Detection of Hydrogen Peroxide Molecules via Turn-off Fluorescence Mechanism

Transition metal dichalcogenides (TMDs) based materials have grabbed striking attention to a great extent owing to their intriguing characteristics for biological, optical, chemical and medicinal applications. Herein, we report in-situ one-pot hydrothermal-synthesis of molybdenum ditelluride@carbon nano-dots (MoTe2@C NDs) and then explored its potency in biosensing. The MoTe2@C NDs have been characterized by using X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and Transmission Electron Microscopy (TEM) for confirmation. Furthermore, the photophysical properties of MoTe2@C NDs have been examined. Under radiation of Ultra-Violet (UV) light (λ = 365 nm), the MoTe2@C NDs emit cyan fluorescence which has been confirmed by photoluminescence (PL) spectroscopy (PL peak at ∼431 nm, excitation wavelength ∼350 nm). The as-synthesized sample has been subjugated for the sensing of hydrogen-peroxide (H2O2) molecules. Notably, with a gradual proliferation of the concentration of H2O2, the PL intensity of the MoTe2@C NDs decreases and is found to be linear (R2 = 0.9986). The detection-limit has also been estimated as 14.22 nM. The PL quenching-mechanism has been elucidated based on three-level kinetic model considering charge separated-trap states (1[D+···A−] ↔ 3[D+···A−]). This is the first work of hydrothermal-synthesis of MoTe2@C NDs and study of its optical properties, which has efficient potential to use as H2O2 sensor in industrial/biomedical applications.