ACS Applied Nano Materials最新文献

The uncontrolled release of industrial wastewater, domestic sewage, and frequent crude oil spills has impacted both the environment and human health. Hence, finding efficient and effective methods to treat oil-contaminated wastewater has become a critical area of focus. Herein, we demonstrate a superamphiphilic titanium-based (Ti-based) nanowire-woven microporous array gate enabling water–oil separation. The results showed that the microporous array gate has the ability to regulate liquid pressure on demand and quickly self-clean its surface. It is reusable multiple times and remains unaffected by the temperature of the oil–water separation liquid. Additionally, the separation flux and efficiency of the microporous array gate can reach up to 37,000 L/m²/h and 99.1%, respectively. Further research reveals that the nanowire structural layer plays a crucial role in the oil–water separation process. This work has potential applications in designing water–oil separation devices with on-demand pressure regulation, self-cleaning capabilities, and high efficiency.

Herein, we propose a hybrid approach for optimizing the carbon nanotube (CNT) dispersion in polypropylene (PP) nanocomposites based on both chemical functionalization and physical confinement. Our approach relies on a two-step scheme where CNTs are first functionalized and dispersed in an ethylene-propylene-diene-monomer (EPDM) rubber phase via solution mixing, followed by a second step where the CNT-reinforced EPDM phase is melt-mixed with PP and taken through the in situ fibrillation process. Morphological characterization supported by rheological analysis show that the CNTs are successfully confined and dispersed within an interconnected network of nanosized rubbery EPDM fibrils, distributed throughout the PP matrix. In addition to reducing the electrical and thermal percolation thresholds from approximately 1.5 to 0.25 wt %, this unique morphology brings significant improvement in the crystallization behavior of the PP nanocomposites, resulting in a more uniform crystallization behavior with both increased percent crystallinity and increased crystallization temperature compared to conventional PP/CNT nanocomposites. This morphology brings also significant improvement in the mechanical properties, raising both the tensile toughness and ductility by three times compared to conventional PP/CNT nanocomposites. All in all, our innovative morphology strikes an excellent balance between high electrical/thermal conductivity and high toughness and ductility presenting them as promising for flexible antistatic packaging and electrostatic dischargers.

The photothermal catalysis of carbon dioxide (CO₂) reduction into value-added solar fuels represents a promising approach to addressing the energy crisis and mitigating global warming. Recent experimental findings indicate that Ru-H_xMoO_3–y is capable of completely converting CO₂ into methane (CH₄). In contrast, Pt-H_xMoO_3–y has been observed to produce a range of products, with carbon monoxide (CO) being the most prevalent. A comprehensive understanding of the reaction mechanism is essential to elucidate the different sensitivities of catalysts and to facilitate the development of H_xMoO_3–y-based catalytic systems. This study employs density functional theory to examine the mechanism of CO₂ reduction on Ru-H_xMoO_3–y. The d⁷ configuration of Ru enables the transfer of d electrons from the Ru-H_xMoO_3–y catalyst to CO via π-back-bond, which results in the weakening of the C–O bond and the preferential formation of CH₄. Moreover, Ru-H_xMoO_3–y has been identified as a promising candidate for the production of ethylene (C₂H₄), with its selectivity being adjustable through variations in reaction temperature and pressure. Our findings demonstrate that the performance of C–C coupling in H_xMoO_3–y-based catalysts is significantly influenced by the d configuration of the metal cluster. The theoretically designed Fe/Ru-H_xMoO_3–y exhibits the most favorable catalytic activity. These insights offer critical mechanistic guidance for the design of advanced photocatalysts to convert CO₂ into solar fuels.

Plasmonic metasurfaces composed of nanodimer repeat units with ultranarrow gaps have strong fields confined to the subwavelength gaps, which can enable resonance wavelength tuning and polarization control. We report a scalable fabrication process that takes advantage of nanoimprint lithography and the solution processability and surface conformability of colloidal nanocrystal dispersions to realize large-area, geometrically engineered nanodimer metasurfaces from a single master template. Geometrical control of the nanodimer gap is achieved through a combination of controlled wet etching of bilayer imprint resists and solution-based nanocrystal deposition and ligand exchange. Using a master template with 50 nm gaps and tailoring the wet etch, nanocrystal concentration, and ligand exchange time, we achieve large-area (1 cm²) metasurfaces with nanogaps tailorable from 72 nm to as narrow as 21 nm, even to the point of fusing the nanorods. We characterize the gap-size-dependent spectral response in the near-infrared, which shows increased electric field confinement and polarization dependence when the gap narrows. This process is promising in its potential for scalable manufacturing and nanogap engineering, using a single master template, of nanodimer metasurfaces, which are of particular interest for applications in refractive index sensing.

The morphology regulation of nanomaterials is an effective approach to improve the intrinsic catalytic performance of Pt-based catalysts for the methanol oxidation reaction. Herein, three templating materials composed of Fe₂P, CoP, and nitrogen-doped carbon (NDC) are designed and synthesized. By adding different surfactants, they presented separately flake-like, hydrangea-like, and sphere-like structures and were respectively named Fe₂P-CoP-NDC(f), Fe₂P-CoP-NDC(h), and Fe₂P-CoP-NDC(s) templating materials. After depositing Pt nanoparticles, flake-like Pt/Fe₂P-CoP-NDC(f), hydrangea-like Pt/Fe₂P-CoP-NDC(h), and sphere-like Pt/Fe₂P-CoP-NDC(s) catalysts were successfully obtained. By specifically discussing the influence of the nanomaterial morphology on the size, dispersion, surface state, exposed crystal facets, and catalytic behavior of Pt nanoparticles, it can be found that the morphology regulation plays an extremely crucial role in improving the catalytic performance. Moreover, compared with flake-like and hydrangea-like nanocatalysts, the sphere-like Pt/Fe₂P-CoP-NDC(s) catalyst with an appropriate porous structure exhibits the best catalytic performance. The catalytic activity of the sphere-like Pt/Fe₂P-CoP-NDC(s) catalyst reaches 1292 mA·mg^–1_Pt in acidic media, surpassing that of the flake-like Pt/Fe₂P-CoP-NDC(f) and hydrangea-like Pt/Fe₂P-CoP-NDC(h) catalysts. Additionally, the Pt/Fe₂P-CoP-NDC(s) catalyst also possesses better anti-CO poisoning ability and catalytic stability. This work elucidates the intrinsic mechanisms through which morphology regulation enhances the electrocatalytic performance over Pt nanoparticles and provides insights into the exploration of high-efficiency Pt-based nanocatalysts.

With the continuous advancement of nanotechnology, nanofluid flooding has become a widely adopted method in the development of oil and gas fields, recognized for its economic viability and efficiency in oil displacement. However, challenges remain regarding nano-oil displacement materials, including low interfacial activity and an ambiguous interfacial mechanism. Therefore, it is crucial to construct nanomaterials with high interfacial activity and investigate their interfacial mechanisms. In this study, we successfully constructed functionalized MoS₂ nanosheets characterized by high interfacial activity (SDS-MoS₂). The SDS-MoS₂ nanosheets exhibited superior interfacial properties, emulsification capabilities, climbing film effects, and oil displacement efficiencies. When a dispersion of the nanosheets at a concentration of 0.01 wt % is injected at 3 pore volumes (PV), the enhanced oil recovery can achieve 18.05%. Based on these findings, the interfacial interaction mechanism of SDS-MoS₂ nanosheets was elucidated through microscopic visual displacement experiments. This research aims to provide theoretical insights into synthesizing high interfacial activity nano-oil displacement materials, analyzing their oil–water interface mechanisms, and advancing the practical application of these materials in oilfield settings.

Surface-enhanced infrared absorption (SEIRA) spectroscopy under highly controlled laboratory conditions has been extensively applied and is important in many areas of material analysis and sensor development. However, their direct application in aqueous environments remains a significant challenge. Addressing this, our study presents a fiber-based SEIRA technique that utilizes replaceable silver halide polycrystalline infrared (PIR) fiber loops. These fiber loops were modified with silver-poly(vinylpyrrolidone) (Ag-PVP) nanoparticles and applied for acquiring SEIRA spectra of naphthalene, a model polycyclic aromatic hydrocarbon. It was demonstrated that naphthalene dissolved in water at a concentration of 50 μM can be detected directly in aqueous environments under in situ conditions. The distinctive spectral band at 783 cm^–1 was used to identify naphthalene in water. An exploratory computational study was conducted to investigate the effect of silver interaction on the naphthalene SEIRA spectrum. The computational and experimental results indicate the absence of a covalent bond of naphthalene to the Ag-PVP nanoparticles, with only physisorption being observed. This study facilitates the applicability of SEIRA to practical, real-world scenarios, including the detection of low-solubility toxic compounds such as naphthalene, which are pertinent to environmental contamination.

Nanozymes offer a cost-effective and stable alternative to natural enzymes but often suffer from limited selectivity, requiring further modifications for targeted applications. This study introduces a distance-regulated electron-transfer (DRET) probe based on nanozymes, designed to enable selective enzymatic responses to specific targets. The hybrid DRET system comprises carbon dot (CD)-conjugated iron oxide nanoclusters (IONs), with interparticle distances controlled by linkers. The system catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), producing a blue color as a readout of enzymatic activity. Compared to its individual components, the DRET system exhibits significantly enhanced enzymatic efficiency, likely due to improved electron transfer facilitated by the CDs surrounding the IONs. By introducing linkers of varying lengths, the relationship between interparticle distance and enzymatic activity was systematically explored. To demonstrate its utility, a glutathione (GSH)-responsive DRET probe was engineered using cystamine as the linker, which is cleaved in the presence of GSH. This cleavage reduces the synergistic enzymatic effect, resulting in a proportional decrease in TMB oxidation and color intensity. The GSH-DRET system showed high specificity for GSH, outperforming responses to ions and other metabolites. Moreover, it enabled accurate detection of GSH concentration in human plasma solution (imitating human samples) via simple absorbance measurements. These findings highlight the potential of the DRET nanozyme system as a versatile field detection tool, with possibilities for expanded applications through diverse linker strategies.

The development of optical hydrogen sensors using wet-chemical methods often faces significant challenges, including slow response times and limited repeatability. This study presents an optical hydrogen sensor with a rapid response time, low detection limit, and excellent recyclability. The sensor uses core–shell Au@Pd NPs as the hydrogen response material. These NPs are self-assembled into a thin film by using an interfacial self-assembly method and then transferred onto a glass slide to form an Au@Pd nanoparticle array (NAs) sensor. The unique morphology of the Pd layer, which offers a high surface area with numerous reactive sites, significantly reduces the response time. By adjusting the Pd layer thickness, an optimal Au_0.31Pd_0.69 NPs composition was achieved, yielding a low detection limit (0.1%) and a fast response time (t₉₀ of 3% H₂ is about 6.2 s) at room temperature(abouts 23 °C). Incorporating PMMA improved the sensor’s cycling performance while maintaining a fast response (t₉₀ of about 8 s for 3% H₂) and low detection limit (0.5%). This work demonstrates a cost-effective and high-performance hydrogen sensor with superior response time, excellent repeatability, and a broad detection range fabricated through wet-chemical methods.

This study introduces a method for fabricating hollow nanoporous carbon cubes (HPCCs), utilizing the selective purification effect of acetone on a small-molecule phenolic resin (PR)/NaCl precursor. The impact of acetone-induced purification on the nanoscale microstructure and electromagnetic wave-absorbing properties of HPCCs is systematically explored. Using a template-etch-carbonization process, the HPCCs exhibit a significant increase in specific surface area from 149.61 m²/g (HPCCs0min) to 315.86 m²/g (HPCCs10min), highlighting the nanoscale structural modifications induced by acetone treatment. At 5 wt % absorber content and a 2.7 mm thickness, HPCCs treated for 10 min demonstrate optimal wave-absorbing performance, achieving a peak reflection loss (RL_min) of −24.1 dB and an effective absorption bandwidth (EAB) of 7.3 GHz. These results underscore the critical role of nanoscale surface area and pore volume modulation in enhancing the electromagnetic wave absorption capabilities of HPCCs.