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Due to their versatile and unique properties, tantalum-based thin films have been extensively studied. However, tantalum is susceptible to oxidation due to its higher chemical activity, which is crucial regardless of whether oxidations of Ta are beneficial or detrimental. Therefore, the oxidation of Ta during material processing, especially without conscious means, should be taken seriously. In this study, pure Ta films were fabricated by magnetron sputtering under set procedure parameters. The effects of base pressure and substrate temperature on the degree of oxidation of Ta films were investigated. The results revealed that the magnitude of the base pressure directly affects the oxidation state of the as-deposited Ta films. When preferably avoiding the oxidation of sputtered Ta films, the base pressure should be controlled below 4.4 × 10−4 Pa. The substrate temperature has little effect on the oxidation state of the as-deposited Ta films under a base pressure ranging from about 10−2 Pa to 10−4. We hope that this study can provide some references for controlling the oxidation states of Ta involved in relevant film preparation. [ABSTRACT FROM AUTHOR]

Direct oxidation of organosilanes is one of the most straightforward ways to access silanols. Herein, we describe a novel photo-induced strategy for oxidation of organosilanes to access silanols, promoted by a photoactive charge-transfer complex (CTC) between sodium benzenesulfinate and molecular O2. A streamlined sequence transformation of organosilanes to silyl ethers was also readily achieved. This developed protocol represents the first example of CTC-based oxidation of organosilanes, offering a facile approach to access a series of silanol and silyl ether products. [ABSTRACT FROM AUTHOR]

A slurry-based laser cladding technique was used to repair the SiC coated carbon/carbon composites. The oxidation resistance of repaired samples at 1773 K for 10 h was investigated. Samples were characterized by X-ray diffraction pattern, scanning electron microscopy and confocal microscope; its interface characteristics were studied with scratch, thermal shock and internal friction tests. The results show that there is no obvious interface between the newly-formed coating and the original coating, and the newly-formed coating has a much smoother surface. With optimizing parameters, the new coating of 180 μm thickness possesses refined grains, flat surface, dense microstructure and good thermal stability. The number of internal defects in the samples repaired by laser cladding drops, compared with the damaged/undamaged samples. The weight loss of repaired samples decreases by 64.8% in comparison with the damaged ones, and it is almost the same with the undamaged samples according to a test of anti-oxidation behaviors. This is attributed to the enhanced oxidation resistance of dense newly-formed coating, which makes carbon/carbon composites well protected. [ABSTRACT FROM AUTHOR]

A porous carbon was synthesized from cotton black liquor. The carbon produced at the optimal condition was used for H 2 S oxidation at 423K at different experimental conditions. The H 2 S oxidation was modeled by a novel CFD approach by coupling the stoichiometric reaction with variation of porosity as the user-defined scalars (UDS). The established model can be a useful tool for studying the fluid dynamics of H 2 S oxidation by AC catalyst at experimental conditions in this work. • A porous carbon (AC) was synthesized from cotton black liquor. • The AC prepared under the optimal condition was applied to the direct H 2 S catalytic oxidation. • Complete parametrical computational fluid-dynamic (CFD) model was constructed. A porous activated carbon (AC) was synthesized from cotton black liquor, and the synthesis process was optimized using response surface method (RSM). The AC prepared under the optimal condition was applied to the direct H 2 S catalytic oxidation. Complete parametrical computational fluid-dynamic (CFD) model, coupling stoichiometric reaction with variation of porosity as the user-defined scalars (UDS), was developed to simulate the removal process. Various experiments, including breakthrough, pressure drops, and H 2 S conversion at different experimental conditions, were carried out. The CFD model was validated by results from the experiments, as the experiment results were found to adequately match model predictions. Hence, the model developed in this study can be a useful tool for studying the fluid dynamics of H 2 S oxidation by AC catalyst at investigated experimental conditions. [ABSTRACT FROM AUTHOR]

The development of eco-friendly and switchable catalytic systems for the conversion of a sole raw-material into distinct high-value products is a particularly attractive concept and a daunting synthetic challenge. In the present work, the first example of efficient and selective oxidation of sulfides to sulfones and sulfoxides using molecular oxygen under clean conditions was established. [ABSTRACT FROM AUTHOR]

• Heat stress induces mitochondrial dysfunction and oxidative changes in duck meat. • Heat stress-responding proteins in duck chest muscle are comprehensively evaluated. • Some proteins are reported for the first time as potential indicators of heat stress in duck. Heat stress causes oxidative damage and quality reduction in poultry. Here, a tandem mass tag proteomic approach was applied to investigate the proteomic differences in duck meat from birds exposed to heat stress. Altogether 212 differential proteins were identified, including 178 down-regulated and 34 up-regulated proteins, compared to the control. Malondialdehyde and carbonyl content and cooking loss of the chest muscle significantly increased under heat stress. The proteomic analysis indicated that heat stress suppressed mitochondrial functions and respiratory chains, which might be responsible for the higher oxidation level. The results also revealed potential protective proteins involved in the defensive mechanisms against heat stress in duck muscles, such as sarcoplasmic/endoplasmic reticulum calcium ATPases, Mn-superoxide dismutase, heat shock protein family B member 7, methyltransferase like 21C, myosin-binding protein C, and carbonic anhydrase 3. These results provide potential targets for the research and identification of oxidative meat products due to heat stress. [ABSTRACT FROM AUTHOR]

Two commercial diatomaceous earths were used as supports for the preparation of Mn/Co binary metal catalysts at different metal loads (5 to 10 wt % Mn and 5 to 15 wt % Co) by incipient wetness deposition. The activity of the prepared catalysts towards the complete oxidation of benzene to CO2 and water was investigated between 100 and 400 °C. Raw supports and synthesized catalysts were characterized by XRD, N2 physisorption, SEM-EDS, H2-TPR, and TPD. The purification treatment of food-grade diatomite significantly affected the crystallinity of this support while reducing its specific surface area (SSA). A loss of SSA, associated with the increase in the metal load, was observed on samples prepared on natural diatomite, while the opposite trend occurred with food-grade diatomite-supported catalysts. Metal nanoparticles of around 50 nm diameter were observed on the catalysts' surface by SEM analysis. EDS analysis confirmed the uniform deposition of the active phases on the support's surface. A larger H2 consumption was found by TPR analysis of natural diatomite-based samples in comparison to those prepared at the same metal load on food-grade diatomite. During the catalytic oxidation experiment, over 90% conversion of benzene were achieved at a reaction temperature of 225 °C by all of the prepared samples. In addition, the formation of coke during the oxidation tests was demonstrated by TGA analysis and the soluble fraction of the produced coke was characterized by GC-MS. [ABSTRACT FROM AUTHOR]

This article highlights recent advances in the development of transition metal-based catalysts for formaldehyde oxidation, particularly the enhancement of their catalytic activity for low-temperature oxidation. Various factors that enhance low-temperature activity are reviewed, such as morphology and tunnel structures, synthesis methods, specific surface area, amount and type of active surface oxygen species, oxidation state, and density of active sites are discussed. In addition, catalyst immobilization for practical air purification, reaction mechanism of formaldehyde oxidation, and the reaction parameters affecting the overall efficiency of the reaction are also reviewed. [ABSTRACT FROM AUTHOR]

To protect carbon/carbon composites against oxidation and ablation, a Fe 2 O 3 modified ZrB 2 –SiC–Si coating was prepared by a two-step pack cementation. The microstructure, oxidation and ablation resistance of the Fe 2 O 3 modified ZrB 2 –SiC–Si coating were studied. The results showed that the Fe 2 O 3 modified ZrB 2 –SiC–Si coating had good oxidation and ablation resistance, and could effectively protect the carbon/carbon composites from oxidation at 1773 K for 150 h and ablation at 2573 K for 60 s. The excellent oxidation and ablation resistance of the coating were mainly attributed to its dense and large amount of ZrB 2 in the coating. [ABSTRACT FROM AUTHOR]

Thiol (–SH) groups within a Zr(iv)-based metal–organic framework (MOF) anchor Hg(ii) atoms; oxidation by H2O2 then leads to acidic sulfonate functions for catalyzing acetylene hydration at room temperature. [ABSTRACT FROM AUTHOR]

The generation of aroma during processing of boneless dry‐cured hams is investigated by evaluating neutral and acid lipases, phospholipase, lipoxygenase (LOX), thiobarbituric acid reactive substances (TBARS) values, fatty acid composition, and volatile substances derived from lipid oxidation (VCDFLO). It is found that moisture content, acid lipase, and phospholipase decreases in the whole processing, but sodium chloride content and TBARS increase. Neutral lipase, LOX, and total fatty acids increase from raw ham to the end of resting and decrease subsequently. 15 VCDFLO containing six ketones, three aldehydes, three hydrocarbons, one alcohol, one carboxylic acid, and one furan are identified. The total peak area of VCDFLO increases during the entire processing and indicates 39.76–40.75% of total volatile compounds. Hexanal, 1‐octen‐3‐ol, octanal, and nonanal are the major characteristic volatiles of boneless dry‐cured hams. Therefore, VCDFLO formation is associated with lipid‐related enzymes and helpful for the aroma. Practical Applications: The pork that has high intramuscular fat content is usually selected to produce boneless dry‐cured hams, because intramuscular phospholipids, and triglycerides are important precursors to produce aroma compounds. Exploring the formation mechanism of flavor associated with lipid oxidation will be beneficial for improving the quality of hams. Therefore, this study demonstrates the relationship between lipolysis‐oxidation and the generation of flavor compounds during the processing of boneless dry‐cured hams. This study demonstrates that thiobarbituric acid reactive substances (TBARS) values can reveal the changed trend of volatile compounds derived from lipid oxidation (VCDFLO) very well, and that lipid‐related enzymes plays an important role in the development of VCDFLO. [ABSTRACT FROM AUTHOR]

[Display omitted] • Controllable Brønsted acid-promoted aerobic oxidation strategy for constructing quinazolinone scaffolds was described. • Facile tunable syntheses of dihydroquinazolinones and quinazolinones have been achieved using the same bis-sulfonated ionic liquids as catalyst and air as oxidant. • The aerobic oxidation process relies on proton activity in reaction medium. • The catalyst could be recovered and reused for gram scale synthesis. A controllable Brønsted acid-driven aerobic oxidation strategy for the efficient and convenient construction of quinazolinone ring system has been developed using bi-SO 3 H-functionalized ionic liquids as catalyst under air atmosphere. The tunable syntheses of dihydroquinazolinones and quinazolinones have been achieved using the same catalyst in different reation meduim via solvation-induced proton transfer. The bi-SO 3 H-functionalized ionic liquids (ILs) catalyst can be readily recovered and reused for the gram-scale application for at least three runs without any significant impact on the yields of the products. The operational simplicity and environmentally benign procedure are synthetically useful features. [ABSTRACT FROM AUTHOR]

The effect of transition metal on oxidation process of ZrB 2 was studied by Density Functional Theory (DFT) and experimental techniques. The energy barriers of O atom diffusion on Hf-doped surface and migration inward are 0.60 eV and 7.67 eV, which are all higher than other surfaces. This is due to electronic structure's regulation of ZrB 2. After oxidation for 8 h, the mass gain of (Zr, Hf) B 2 is 11.34 %, which is lower than other ceramics. It indicates that (Zr, Hf) B 2 has excellent oxidation resistance. The thickness of oxidation layers of (Zr, Hf) B 2 is lower than that of ZrB 2. • The Zr-terminated surface is more susceptible to oxidation than B-terminated surface. • Hf atom can inhibit the diffusion of O atom on the ZrB 2 (0001) surface at 1773 K. • The electronic structure's regulation changed the migration barriers of O atoms. • (Zr, Hf) B 2 has the best oxidation protection ability at 1773 K than others. [ABSTRACT FROM AUTHOR]

To improve the bonding properties of the interface between carbon/carbon (C/C) composites and a Ti-Ni-Si interlayer, an interlocking interface structure was obtained by a two-step technique involving pre-oxidation and hot-pressing. The results show that a porous layer could be obtained on the surface of C/C composites by pre-oxidation treatment at 1173 K in air and that an interlocking C/C-Ti-Ni-Si interface was formed after hot-pressing. With increasing pre-oxidation time, the average shear strength of the Ti-Ni-Si joint initially increased and then decreased. After a pre-oxidation time for 3 min, the shear strength of the joint reached a maximum of 29.81±1.76 MPa, which is 20.1% higher than the joint strength obtained without pre-oxidation. The improvement in the shear strength is primarily attributed to the ‘pinning effect’ generated by the interlocking interface, which could play a positive role in extending the crack propagation path by inducing crack deflection. [ABSTRACT FROM AUTHOR]

An ablation resistance ZrC coating composed of micrometer particles was prepared on carbon/carbon composites by chemical vapor deposition. The structure evolution, ablation property and behavior of the coating were investigated under an oxyacetylene torch environment with different heat fluxes. Results show that the ablation performance decreases with the increase of heat fluxes from 2380 to 4180 kW/m 2 . Oxidation erosion is proposed as the major ablation mechanism. The ablated coating consists of three layers (outer ZrO 2 layer, transitional ZrC x O y layer and residual ZrC layer). An oxidation progress that the ZrC is oxidized into ZrC x O y firstly and then into ZrO 2 is inferred and accelerated by the continuous diffusion of oxygen resulted from the increase of heat fluxes. During different heat flux environments, the coating exhibits efficacious mechanical denudation resistance and the formed transitional ZrC x O y and outer ZrO 2 layers act as a good oxygen diffusion barrier, which could be the reason for its high ablation resistance at the temperature of 2000–3000 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

Carbon/carbon (C/C) composites are considered the most promising materials for high-temperature structural applications owing to their excellent properties at high temperature. However, oxidation and ablation limits their applications in oxygen-containing environments at ultrahigh temperatures and high-speed gas flows. How to improve oxidation and ablation resistance of the C/C composites has become a critical issue. The methods for improving oxidation and ablation resistance of the C/C composites are reviewed, which mainly focus on optimizing the carbon fiber weave structure, controlling the pyrolytic carbon texture, modifying the matrix, and coating with anti-ablative ceramic layers. Matrix modification and coating technology have been proved to be the two effective ways of dealing with the problem. Development directions on producing oxidation and ablation resistive C/C composites are concentrated on decreasing preparation cost, controlling pyrolytic carbon texture, optimizing compositions of the doped ceramics used in the matrix and the coating layer, and combining matrix modification with an anti-ablation coating. [New Carbon Materials 2015, 30(2): 97–105] [ABSTRACT FROM AUTHOR]

To increase the oxidation resistance of carbon/carbon (C/C) composites at high temperature, it was modified by ZrB 2 –SiC ceramics with precursor infiltration and pyrolysis process, then SiC coating was prepared on the modified composites by pack cementation. The results show that the SiC coating prepared with Si/C weight ratio of 6:0.5 has better oxidation resistance, It can effectively protect C/C composites for 100 h at 1773 K with the weight gain per unit area of 7.75 g cm −2 . The good oxidation resistance of the coated composites is attributed to the formation of dense SiO 2 glass during the oxidation test. [ABSTRACT FROM AUTHOR]

To improve the bonding strength and thermal shock resistance of SiC coating for C/C–ZrC–SiC composites, a transition layer with mechanical interlocking structure was constructed at the interface by pre-oxidation treatment and chemical vapor deposition. For the coated specimens with pre-oxidation treatment at 1073 K for 5 min, the bonding strength increased from 2.0 to 4.0 N, and the mass loss percentage decreased by 52.5% after 12-time thermal cycling between 1773 K and room temperature in air. The transition interlocking structure can effectively alleviate the mismatch between the coefficients of thermal expansion of SiC coating and C/C–ZrC–SiC substrate, improving the bonding strength and thermal shock resistance. As the pre-oxidation time increases, a rugged and loose ZrO 2 –SiO 2 layer will be formed at the interface, which is disadvantageous to the bonding strength and thermal shock resistance of SiC coating for C/C–ZrC–SiC composites, and results in the debonding and collapse of the coating. [ABSTRACT FROM AUTHOR]

Abstract: A C/SiC oxidation resistance coating was prepared on carbon/carbon (C/C) composites by slurry and pack cementation. The microstructure, oxidation resistance and mechanical properties of C/SiC coating prepared from 1773 to 2573K were investigated. With the increase of the preparation temperature, the oxidation resistance of C/SiC coating increases, however, the flexure strength decreases gradually. The preparation of C/SiC coating on C/C composites results in the fracture behavior of C/C composites changing from pseudo-plastic to brittle failure model. The decrease of flexure strength is mainly attributed to the decrease of C/C matrix’ flexure strength at high temperature. [Copyright &y& Elsevier]

Catalytic oxidation is a promising approach to eliminating formaldehyde (HCHO) to improve indoor air quality. Herein, CeO 2 was explored due to its remarkable properties for oxygen storage and oxygen transfer capability for co-doping δ-MnO 2 alongside cobalt for enhanced low-temperature oxidation of HCHO. Various characterization techniques were deployed to understand the morphology and physicochemical properties of the synthesized catalysts. The Co-Ce co-doped catalysts with low CeO 2 loading (0.05 and 0.1) showed higher catalytic activity for HCHO oxidation due to their higher concentration of surface-active oxygen species. Catalytic oxidation results showed that the presence of CeO 2 leads to the generation of methanol as a secondary hazardous pollutant. Methanol selectivity increases with increasing CeO 2 loading in the catalysts. The results from in-situ DRIFTS confirmed the formation of methoxy species in the presence of CeO 2 , which are intermediates for methanol generation. Considering the recent interest in CeO 2 as a potential catalyst for practical abatement of HCHO from the indoor environment, this work has thus raised questions on the safety of using CeO 2 as a catalytic material for HCHO oxidation. It also provides insights into the surface reaction mechanism leading to the generation of methanol in the presence of CeO 2. [Display omitted] • Bimetallic co-doping of δ MnO 2 with Ce and Co does not enhance HCHO oxidation. • High CeO 2 doping results in the structural collapse and lower catalytic activity. • CeO 2 leads to the generation of methanol during the catalytic oxidation. • Cannizzaro disproportionation reaction is proposed for methanol generation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The damaged SiC coated C/C composites was repaired successfully. • A Mo-modified Si-SiC coating was prepared on C/C composites by laser-inducing. • The free Si of the Si-SiC coating was decreased significantly by Mo-modification. • The interface bonding of the coating modified with 10 wt% Mo was the best. • The oxidation resistance of the repaired coating was improved significantly. As the thermal structural component of aircraft, SiC coated C/C composites will fail and cause catastrophic consequences once the SiC anti-oxidation coating is damaged. Therefore, it is extremely important to develop a coating repair system with excellent oxidation protection performance. In this study, a Mo-modified Si-SiC coating was prepared by laser-inducing to repair the damaged SiC coated C/C composites. Thermal shock test between room temperature and 1773 K was conducted to study the interface bonding and 1773 K cyclic oxidation test was performed to examine the repair effect. With 10 wt% Mo-modification by laser-inducing, MoSi 2 precipitated at the interfaces while the interface bonding was not weaken. The decreased free Si, densified structure of coating and enhanced self-healing ability, which were obtained by modifying, contributed to reduce the mass loss after oxidation by ∼ 70% compared with the damaged sample without repairing. [ABSTRACT FROM AUTHOR]

In this work, we designed and synthesized a ratiometric fluorescent sensor (POC) based phenazine derivative which can specifically detect hypochlorite (detection limit equals to 8.9 × 10−7 M) in DMSO/H 2 O (3:7, v/v) solution. With addition of hypochlorite to the solution of POC , hypochlorite broken π-π stacking of POC , and then oxidizes sulfur atoms in phenazine groups to sulfoxide, which resulted in the fluorescent color changed from blue to yellow. Job's plot showed that binding stoichiometry of POC with ClO− was 2:1. In addition, POC could be used to real-time detect hypochlorite in environment samples, and the naked eyes detection limit reached up to 7 × 10−5 M. In this work, we designed and synthesized a phenazine derivative (POC) based fluorescent sensor which could high selectivity detect hypochlorite in DMSO/H 2 O (3:7, v/v) solution. Image 1 • A novel fluorescent sensor for highly selective and sensitive detection of hypochlorite. • Taking advantage of a simple mechanism of oxidation reaction. • The test strips could conveniently and rapidly detect hypochlorite solutions. • POC could serve as a fluorescent sensor material for detecting the active ingredient in 84 disinfectant. [ABSTRACT FROM AUTHOR]