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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]

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]

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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]