Surfaces and Interfaces最新文献

Developing tunable gas sensors is pivotal for advancing the embodied perception of robots. In this study, first-principles calculations explore the adjustable sensing capabilities of BiSb monolayers towards ethanol gas under external biaxial and uniaxial strain. The results indicate a reduction in adsorption energy with increasing tensile strain in both biaxial and b-directional uniaxial conditions. Furthermore, strain effectively modulates the electronic structure of the adsorption system. Additionally, computed recovery times suggest that BiSb monolayers face significant challenges in ethanol gas desorption without strain, making them unsuitable for gas sensing under normal conditions. However, under strain, BiSb monolayers demonstrate potential as gas sensors for ethanol detection. These findings introduce novel avenues for enhancing the sensing performance of BiSb monolayers and underscore their prospective application as reversible sensors for ethanol detection.

This review provides a concise yet comprehensive exploration of single atom catalysts (SACs) in air pollution control. It begins with an overview of air pollution challenges and the emergence of SACs as a novel solution. The paper discusses the fundamentals of SACs, including their unique properties and the importance of surface engineering. Various synthesis strategies for SACs are examined, from wet-chemistry to electrochemical methods. The review also delves into the application of SACs in degrading harmful gases, treating volatile organic compounds, and reducing particulate matter. Additionally, it includes a life cycle assessment to evaluate the environmental impact of SACs. The paper concludes with a discussion on the challenges and future directions in the field, emphasizing the role of SACs in sustainable air quality management.

People have recently shown increasing interest in wearable and flexible electronics. Due to their high electrical conductivity and flexibility, carbon nanofibers can be utilized for various flexible applications. However, pure carbon nanofibers have low capacity, which makes it challenging to achieve high capacity for flexible applications. Herein, sandwich-like nanofibers - nickel disulfide@carbon nanofibers - carbon nanofibers are obtained through a multi-step electrospinning process to serve as a flexible binder-free anode for lithium-ion batteries. This strategy stabilizes the structure well with two layers of carbon nanofibers, effectively accelerating the Li⁺diffusion and promoting the electrolyte infiltration. Accordingly, the electrode exhibits a discharge capacity of 551.8 mAh g^-1 at 0.1 A g^-1 after 100 cycles and achieves a discharge capacity of 523.8 mAh g^-1 at 1 A g^-1 after 1000 cycles, demonstrating excellent cyclic stability and high capacity for Li⁺ storage. The kinetic analysis also reveals that the sandwich structure provides a higher capacity contribution. This work introduces a novel approach for creating flexible binder-free anodes with high performance, effectively expanding the application of sulfides through electrospinning.

Obtaining white anodic aluminum oxide (AAO) is a major challenge in the surface finishing industry. The present work presents a cost-effective route to design light-scattering morphologies through submicrometric hollows homogeneously dispersed in the depth of the oxide layer, created by localized hydrogen evolution. To this end, cathodic steps are added in alternance with anodic steps in a bipolar pulse anodizing process performed in 2 M sulfuric acid. The mechanisms of nucleation and growth of the targeted hollows within the AAO are highlighted by combining in situ electrochemical measurements and high magnification SEM observations. The aesthetic performances in terms of white color, evaluated by reflectance spectroscopy in comparison with a white reference, are directly related to the size, shape and distribution of the hollows, controlled by both the parameters of the cathodic step and the thickness of the unit anodic oxide layers.

Surface preparation is very important for the adhesion of thermal sprayed coatings. In this work, the effect of surface preparation on the adhesion strength of suspension plasma sprayed (SPS) Al₂O₃ coatings is investigated. Aluminum (Al-2024) substrates were micromachined by femtosecond laser (FSL) and also mechanically blasted by conventional grit blasting for surface preparation prior to SPS coating. Surface morphology results showed laser-induced periodic surface structures (LIPSS) produced by FSL, whereas grit blasting produced random irregularities with peaks and undercuts. Surface chemistry analysis showed that the FSL-prepared substrates were functionalized by -OH and O, while the grit-blasted substrates were not functionalized. The prepared substrates were coated by the SPS process under two spray conditions, where one condition was selected to produce a dense coating and the other condition was selected to produce a porous coating. The dense coating showed poor adhesion regardless of surface preparation, while the porous coating showed good adhesion for both grit-blasted and FSL-treated substrates. The adhesion strength of the porous coating was evaluated using the ASTM C-633 pull test protocol. A significant improvement (4.5 factors higher) in adhesion strength was achieved for the FSL-prepared substrates compared to the grit-blasted substrates. The improved adhesion of the FSL-prepared substrates was assessed by surface chemistry and surface morphology analyses of the prepared substrates, as well as by further analysis of the failed samples after the adhesion test and splat analysis. Results from this research showed that FSL has potential as an effective surface preparation technique for SPS.

The film with a composition close to Ge₂Sb₂Te₅ was fabricated by the supercycle atomic layer deposition (ALD) of GeTe and SbTe, followed by tellurization annealing. Supercycle processes are widely used for thin film deposition of multicomponent materials and often exhibit non-ideal growth behavior. Since only in situ analysis can reveal the substrate-dependent growth behavior, we used in situ quartz crystal microbalance (QCM) to study the growth mechanism during ALD supercycle processes at 85 °C. GeTe grown on SbTe was more Te-deficient than continuously grown GeTe film. As a result, more Te-deficient Ge-Sb-Te films were formed than expected. By annealing in a Te ambient at 250 °C, the Te-deficient Ge-Sb-Te film was converted to the Ge_0.23Sb_0.23Te_0.54 close to Ge₂Sb₂Te₅ film, which had a high density equivalent to 95 % of the FCC structure of Ge₂Sb₂Te₅. The film showed excellent conformality and uniform composition in a trench pattern, suggesting a uniform crystallization temperature of 118 °C at all locations.

Oxygen corrosion of the aluminum alloy has a substantial impact on the durability of engineering materials and equipment. To better understand how various alloy elements affect oxygen corrosion, we used first-principle DFT method to study the role of each given dopant atom (Be, Mg, Ca, B, Ga, C, Si, and Ge) in the formation of surface oxide film on the Al (111) surface, in the case replacing a surface Al atom. Our calculations show that the electron gain or loss abilities of these alloy elements differ from that of Al metal, with Be, B, C, and Si atoms tending to penetrate into the surface, Mg, Ca, and Ga atoms protruding, and Ge atom just embedded into the Al (111) surfaces. Additionally, the type of doping element at the Al (111) surface can greatly affect the O₂ absorption, predicting that Ca-doped surface absorb the least amount of oxygen, followed by Si-doped surface, with Be-, Mg-, B-, Ga-, C-, and Ge-doped surfaces showing higher O₂ absorption. Based on adsorption energy (E_ads) and partial density of states (PDOS) analysis, we conclude that the doped Al (111) surfaces can make O₂ adsorption different owing to the difference in electronic properties of the doping atoms. These insights draw a greater knowledge of the role of alloy elements in the oxygen corrosion of Al alloys, enabling guidance for designing more corrosion-resistant materials.

Overuse of antibiotics has reduced effective medications, requiring research to combat drug-resistant bacteria and superbugs. This work explores the synthesis of a p-n junction ZnO/Ag₂O composite for antibacterial photodynamic therapy. The as-prepared sample was thoroughly characterized using optical and structural analyses, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. Our ZnO/Ag₂O composite outperformed pristine ZnO in deactivating bacterial while also demonstrating high biocompatibility with normal cells. In silico molecular docking demonstrates that ZnO/Ag₂O composite has a strong binding affinity for bacteria proteins, which exhibits great antibacterial activity against E. coli and S. aureus.

Superhydrophobic coatings are vital in energy, aerospace, and chemical engineering, while their complex preparation and limited durability hinder widespread application. Therefore, inspired by the unique structures of hydrophobic cotton surfaces and mosquito eyes in nature, a durable aluminum alloy superhydrophobic surface is developed using a combination of femtosecond laser and chemical modification methods. Initially, porous microneedle micro-nanostructures are ablated on the surface of the aluminum alloy via femtosecond laser technology. Then, epoxy resin modified with γ-aminopropyl triethoxysilane (KH550) forms a covalently bonded intermediate layer. Finally, biphasic silicon dioxide (BP-SiO₂) nanoparticles modified by hexadecyltrimethoxysilane (HDTMS) are used to construct the top hydrophobic layer. The covalent interface interactions between the aluminum alloy substrate and the intermediate layer, as well as between the intermediate layer and the top layer, significantly enhance the durability of the superhydrophobic surface. The prepared F-M@KH-EP/BP-SiO₂ coating exhibits outstanding superhydrophobic properties, with a water contact angle (CA) as high as 168.56° and a sliding angle (SA) as low as 1.52° More encouragingly, the composite coating maintains its excellent water resistance even when subjected to harsh mechanical durability damage, including sandpaper wear, tape stripping tests, water drop and sand impact tests. Moreover, the prepared coatings maintain distinguished non-wettability in harsh operating conditions such as corrosive liquid environments, ultraviolet radiation, ultrasonic vibration, etc. Additionally, the coating demonstrates remarkable self-cleaning properties. Superhydrophobic surface durability is significantly enhanced by combining nanoparticle-induced bipolar interface effect and micro-nano structures. These findings provide theoretical reference for the design and application of durable superhydrophobic coatings.

This study reported the stable low friction of sp² nanocrystallited carbon films in vacuum environment. Carbon film with larger sp² nanocrystallites size demonstrated consistently low friction in different vacuum pressures. The lowest friction coefficient arrived 0.018 at 10^–6 Pa with a long stable sliding cycles. The mechanisms were ascribed to the stable contact interfaces formed by the rapidly transferred sp² nanocrystallites and the oxidation passivation layer. The low shear force at the nanocrystallited interface reduced the friction and the oxidation passivation promised the stabilization of interface. Carbon film with smaller sp² nanocrystallite size only achieved low friction of 0.023 at 10^–6 Pa, and the film exhibited high friction at 10^-1∼10^-3 Pa due to the insufficient passivation and large dangling bonds. As pure carbon film, sp² nanocrystallited carbon films offer broadly application possibilities for vacuum micro-/nano- devices.