ACS Applied Nano Materials最新文献

Molybdenum oxides and sulfides stand out as promising materials for chemiresistive gas sensors. In this study, we tailored MoS₂/MoO₂ heterostructures, adapting pyrolysis-assisted in situ sulfidation of hydrothermally grown MoO₃ by tuning the concentration of the sulfur source. The MoS₂ flakes adorning a MoO₂ cuboid rod heterostructure represent the n-type semiconducting property, confirmed by Hall measurement. Notably, the sensor demonstrated dual selectivity toward NH₃ and NO_x at room temperature. To our knowledge, the dual selectivity of the MoS₂/MoO₂ heterostructure has not been reported previously. The heterostructure, characterized by a higher carrier concentration, displayed enhanced sensitivity, yielding responses of 10.3 and 8.4% to 10 ppm of NH₃ and NO_x, respectively. The lowest detection limits were 0.32 ppm for NH₃ and 0.29 ppm for NO_x. Furthermore, the heterostructure sensor exhibited commendable cyclic stability and device reproducibility. A long-term stability assessment over 50 days revealed that the response of the sensor remained at 98.6 and 98.4% toward NH₃ and NO_x, respectively. Our results show that the optimized n–n heterojunction between MoO₂ and MoS₂ offers superior sensitivity to NH₃ and NO_x at room temperature. The results could have potential for the development of dual gas sensors suitable for real-time applications.

Heterogeneous multilayer configurations are discussed to enhance plasmonic hydrogen sensors (PHSs). Five sensor designs─pure Pd, Pd/Ag, Ag/Pd, Ag/Pd/Ag, and Pd/Ag/Pd─were developed by sequentially depositing Ag and Pd on nanosphere arrays. The Pd/Ag/Pd configuration demonstrated maximum 10, 2.7, and 1.69 times superior performances in rapid hydrogen sensing, signal detection, and reduced limit of detection (LOD) compared to pure Pd sensors. The impact of material composition, ambient interactions, intermaterial coupling, and surface morphology on sensitivity and response time was quantitatively analyzed using one-hot encoding and linear regression. Finite-difference time-domain (FDTD) calculations were employed to reveal the near-field surface plasmon resonance (SPR) effects. This study would offer theoretical insights and guiding principles for future PHS advancements, particularly in enhancing sensor performance through a heterogeneous multilayer configuration.

Taking advantage of the unique structural directionality of ionic liquids, we successfully synthesized highly concentrated gold nanoparticles (AuNPs) in 1-octyl-3-methylimidazolium chloride (OMImCl) using tetrabutylammonium borohydride (TBABH₄) as the reducing agent. It is a distinctly different approach, avoiding additional capping agents and producing spherical AuNPs of approximately 10 nm diameter at varying concentrations. To prevent nanoparticle aggregation during catalytic reactions and enhance catalyst reusability, these AuNPs were immobilized in cellulose films. The film fabrication involved blending each AuNP dispersion with microcrystalline cellulose dissolved in 1-butyl-3-methylimidazolium chloride (BMImCl) and further water regeneration. Therefore, these films, containing up to 1.30% AuNPs, efficiently reduced 4-nitrophenol (4-NP) using sodium borohydride. Remarkably, the catalysts remained effective through five cycles without noticeable degradation. Compared to other methods, our catalysts displayed a higher turnover frequency (TOF), especially in films with lower gold content, due to their smaller particle size and uniform distribution. Our approach, avoiding the need for complex recovery processes typical of powder-based catalysts, offers an environmentally friendly, efficient, and reusable solution, emphasizing its potential for robust catalytic applications.

Traditional pesticide emulsion formulation may exert deleterious effects on the environment and even induce stress on nontarget crops in the vicinity. In this study, γ-cyclodextrin (γ-CD)-encapsulated azobenzene derivative nanovesicles were synthesized and loaded with pendimethalin to obtain pendimethalin-loaded γ-CD/azobenzene derivative nanovesicles. Upon exposure to ultraviolet irradiation or sunlight, the azobenzene derivatives are converted from the trans- to cis- configuration, leading to the dissociation of the ternary host–guest complexes, resulting in the vesicle rupture and the subsequent release of pendimethalin. Further investigations were conducted on the γ-CD/azobenzene nanovesicles. According to the release characteristics of herbicides, the release rate of pendimethalin under ultraviolet light (365 nm) or sunlight conditions reached 88.3 ± 3%, which was 4.3 times higher than that under dark conditions, demonstrating excellent photocontrolled release behavior. Pot experiments showed that the herbicidal activity of pendimethalin-loaded nanovesicles against Portulaca oleracea (L.) and Echinochloa crusgalli (L.) Beauv. at the recommended dose was comparable to that of the pendimethalin technical under illuminated conditions. Furthermore, genotoxicity experiments reveal a notable increase in the mitotic index of onion root tip cells treated with pendimethalin-loaded nanovesicles, indicating that it had minimal inhibitory effect on cell metabolism and the genotoxicity was lower than that of pendimethalin technical. Pendimethalin-loaded nanovesicles exhibited favorable stability and photoresponsive performance. These findings reveal a promising avenue for responsive material design and release modulation using such nanovesicle systems, providing insights into their potential applications in targeted pesticide delivery systems.

The integration of plasmonic effects in nano electrocatalysis has emerged as a promising avenue for advancing biosensing and energy production technologies. Termed “direct plasmon-accelerated electrocatalysis (PAE)”, this innovative approach harnesses the synergistic interplay between plasmonic materials and electrocatalysts to enhance the efficiency and selectivity of electrochemical processes. By leveraging the unique optical properties of plasmonic nanoparticles, specifically localized surface plasmon resonance (LSPR), coupled with their ability to modulate the local electromagnetic field and promote hot charge transfer, this novel concept holds significant potential for driving advancements in biosensing applications and sustainable energy generation. Moreover, efficiency is ultimately and firmly dependent on the composition and structure of plasmonic metal nanomaterials and their surroundings. Scientists all over the world have done significant research, both theoretical and experimental, on how light interacts with metal nanoparticles to create stronger effects. This opens up a new challenge: combining this with nanoscale electrochemistry to make even more powerful applications. Within this article, we embark on a comprehensive exploration of the fundamental principles, intricate mechanisms, and the latest advancements in direct plasmon-accelerated electrocatalysis by gold nanostructures (Au NSs). Our aim is to provide a deeper understanding of how this technology extends its influence across diverse domains encompassing electrochemical reactions and biosensing applications enhanced by plasmonics. Additionally, we engage in a candid discussion regarding the persistent challenges and the promising avenues that lie ahead, painting a vivid picture of future opportunities in this exciting field.

We present CdSe@CdS nanorods coated with a redox-active polydopamine (PDA) layer functionalized with cobaloxime-derived photocatalysts for efficient solar-driven hydrogen evolution in aqueous environments. The PDA-coating provides reactive groups for the functionalization of the nanorods with different molecular catalysts, facilitates charge separation and transfer of electrons from the excited photosensitizer to the catalyst, and reduces photo-oxidation of the photosensitizer. X-ray photoelectron spectroscopy (XPS) confirms the successful functionalization of the nanorods with cobalt-based catalysts, whereas the catalyst loading per nanorod is quantified by total reflection X-ray fluorescence spectrometry (TXRF). A systematic comparison of different types of cobalt-based catalysts was carried out, and their respective performance was analyzed in terms of the number of nanorods and the amount of catalyst in each sample [turnover number, (TON)]. This study shows that the performance of these multicomponent photocatalysts depends strongly on the catalyst loading and less on the specific structure of the molecular catalyst. Lower catalyst loading is advantageous for increasing the TON because the catalysts compete for a limited number of charge carriers at the nanoparticle surface. Therefore, increasing the catalyst loading relative to the absolute amount of hydrogen produced does not lead to a steady increase in the photocatalytic activity. In our work, we provide insights into how the performance of a multicomponent photocatalytic system is determined by the intricate interplay of its components. We identify the stable attachment of the catalyst and the ratio between the catalyst and photosensitizer as critical parameters that must be fine-tuned for optimal performance.

Slender springtails (Entomobrya nivalis) and orange springtails (Neanura muscorum) are capable of repelling water and organic liquids using the hexagonally arranged nanoscale waxy protrusions and microscale wrinkles on their cuticles to protect the skin-breathing arthropods against suffocation in diversified survival environments. The omniphobic hierarchical structures can even shed and directionally transport liquids along the longitudinal direction of the wrinkles. Bioinspired by springtails, monolayer colloidal crystals are self-assembled onto anisotropic microwrinkled substrates and serve as structural templates to pattern antiwetting hierarchical structure arrays. The dependence of structure configuration on the antiwetting performances is systematically investigated in this study. Impressively, the optimized structure array exhibits anisotropic omniphobic sliding characteristics toward liquids with varied surface tensions ranging from 72.8 to 27.2 mN/m. The springtail-inspired coatings undoubtedly have great potential for developing innovative applications that require directional transportation and the collection of liquids.

CdSe/CdS quantum rods (QRs) are excellent photoluminescent nanomaterials for display applications owing to their large Stokes shift and narrow emission line width. However, integrating QRs into phosphor-converted light-emitting diodes (Pc-LEDs) poses challenges due to their significant fluorescent quenching and long-term instability. Here, we developed a nanocomposite structure to enhance the efficiency and stability of QRs by embedding them in a layer-by-layer assembled BN nanoplate via SiO₂ cross-linking. The two-dimensional SiO₂/BN assembly structure facilitates effective scattering to blue light, which improves the light absorption and minimizes the required amount of QRs to suppress light reabsorption. Furthermore, the BN nanoplates provide effective heat conduction to reduce thermal-induced fluorescence quenching of QRs in Pc-LEDs. The CdSe/CdS/SiO₂/BN assembly structure (QRBNs)-based Pc-LEDs demonstrate significantly improved efficiency and long-term stability.

In this paper, we present an efficient and rapid method for synthesizing perovskite nanoparticles (PeNPs) using ultrasonic spray techniques. The synthesized PeNPs are notably larger than the exciton Bohr radius of perovskite, avoiding the quantum confinement effect, and exhibit a size distribution of around 61.6 ± 30 nm. They show an exceptionally narrow full width at half-maximum of approximately 21.8 nm and a high exciton binding energy (E_b) of approximately 204 meV. Furthermore, the physically restrained reprecipitation method not only effectively transforms perovskite precursor droplets into solid PeNPs at the interface of an antisolvent but also concurrently achieves ligand passivation. This dual-action mechanism promotes their dispersion in various organic solvents and highly concentrated solutions, thus significantly expanding the scope of potential optoelectronic applications such as light-emitting diodes and photodetectors.

Anodization of transition metals, particularly the valve metals (V, W, Ti, Ta, Hf, Nb, and Zr) and their alloys, has emerged as a powerful tool for controlling the morphology, purity, and thickness of oxide nanostructures. The present review is focused on the advances in the synthesis of micro/nanostructures of anodic tantalum oxides (ATO) in inorganic, organic, and mixed inorganic–organic type electrolytes with critically highlighting anodization parameters, such as applied voltage, current, time, and electrolyte temperature. Particularly, the growth of ATO nanostructures in fluoride containing electrolytes and their applications are briefly covered. The details of the current– or voltage–time transient and its relation to the growth of the anodic oxide films are presented systematically. The main discussion revolves around the incorporation of various electrolyte species into the surface of ATO structures and its effects on their physicochemical properties. The latest progress in understanding the growth mechanism of nanoporous/nanotubular ATO structures is outlined. Additionally, the impact of annealing temperature (ranging from 400–1000 °C) and atmosphere on the crystalline structure, morphology, impurity content, and physical properties of the ATOs is briefly described. The common modification methods, such as decorating with other transition metal/metal oxide, heteroatom doping, or generating defects in the ATO structures, are discussed. Besides, the review also covers the most promising applications of these materials in the fields of capacitors, supercapacitors, memristive devices, corrosion protection, photocatalysis, photoelectrochemical (PEC) water splitting, and biomaterials. Finally, future research directions for designing ATO-based nanomaterials and their utilities are indicated.