ACS Applied Engineering Materials最新文献

In this work, we first report the use of palladium–boron–phosphorus (PdBP) ternary alloys as highly efficient nitrobenzene hydrogenation catalysts, where these alloys feature mesoporous and metal–metalloid–nonmetal ternary alloy nanostructures. The mentioned mesoporous PdBP alloys (m-PdBP) were synthesized by a one-pot aqueous coreduction method followed by loading them on alumina to obtain m-PdBP/Al₂O₃ nanocatalysts. At 45 °C, a nitrobenzene/Pd molar ratio of 2500/1 and atmospheric hydrogen pressure, m-PdBP/Al₂O₃ could achieve 98% conversion of nitrobenzene at the a reaction time of 30 min. m-PdBP/Al₂O₃ is comparable to state-of-the-art Pd-based catalysts for nitrobenzene hydrogenation at atmospheric hydrogen pressure. Characterizations and theoretical calculations indicate that the improvement of catalytic performance can be attributed to the alloying effect of the incorporation of B and P into palladium, which facilitates the desorption of aniline and thus promotes the hydrogenation activity.

Multifunctional flexible textile conductors, such as those capable of physiological signal detection, electromagnetic interference (EMI) shielding, and thermal management, are highly desirable for stretchable and wearable electronic devices, but there are still challenges in good performance and conformability on human skin. Liquid metals (LMs) possess ideal characteristics such as fluidity, high conductivity, and low toxicity, making them inherently soft and suitable for the fabrication of wearable biosensors. In this work, a multifunctional wearable liquid metal-coated stretchable olefin block copolymers (OBCs) film with high elasticity and conductivity, incorporating a three-dimensional conductive network, is developed for EMI shielding, motion monitoring, bioelectric monitoring, and Joule heating via an electrospinning method and spraying process. The OBCs film exhibited outstanding elasticity with a large elongation strain of 1560% and a high tensile strength of 0.48 MPa. The excellent conductivity of liquid metal endows the LM/OBCs with an outstanding EMI shielding performance of 69.38 dB; even after 1000 stretching cycles, the average EMI SE remains at 58.89 dB. Attributed to the high elasticity of the OBC, the prepared film exhibited a wide sensing range and fast response of 200 ms, indicating excellent motion monitoring capability. When employed for electrocardiography and electromyography, the LM/OBCs exhibited good conformability to skin and precise signal quality, outperforming commercial electrodes. Additionally, the Joule heating temperature of the LM/OBCs could be up to 71.9 °C at a low supplied voltage of 0.4 V. This work demonstrates that the stretchable LM/OBCs film suggests great potential for multifunctional smart textiles and flexible wearable electronics.

Aerosol contamination presents significant challenges across various industries, ranging from healthcare to manufacturing. Over the past few years, open foam filters have gained prominence for their ability to efficiently capture particles while allowing reasonable airflow. In this work, we present the use of 3D-printed idealized open foam-like lattice structures as aerosol filtration media, leveraging advances in additive manufacturing to generate these highly tunable and modular filters. Using parametric design approaches, we fabricated lattice filters with four different unit cell geometries (Cubic, Kelvin, Octahedron, and Weaire-Phelan) via Digital Light Synthesis 3D printing and characterized these structures with X-ray microcomputed tomography. We compared the aerosol filtration performance of the different lattice unit cell geometries using 1 μm polystyrene latex (PSL) aerosol particles, finding the filtration performance to be positively correlated with the single-unit-cell specific surface area. We then expanded our evaluation of deposition efficiency in Kelvin cell lattice structures of varied porosities, again finding a correlation between the specific surface area and deposition performance. Experimental analysis confirmed that deposition primarily occurs through impaction and electrostatic mechanisms within the parameter space. Overall, our findings demonstrate that unit-cell-based lattices can achieve a wide range of aerosol filtration efficiencies (∼10-100%) across various operating conditions (1-4 m/s superficial velocity), offering a highly tunable in-line filtration medium capable of maintaining high efficiency even at elevated airflow rates. This work not only provides essential guidelines for designing and manufacturing 3D-printed lattices as customizable aerosol filters but also highlights the current limitations and challenges in producing these structures.

Aerosol contamination presents significant challenges across various industries, ranging from healthcare to manufacturing. Over the past few years, open foam filters have gained prominence for their ability to efficiently capture particles while allowing reasonable airflow. In this work, we present the use of 3D-printed idealized open foam-like lattice structures as aerosol filtration media, leveraging advances in additive manufacturing to generate these highly tunable and modular filters. Using parametric design approaches, we fabricated lattice filters with four different unit cell geometries (Cubic, Kelvin, Octahedron, and Weaire–Phelan) via Digital Light Synthesis 3D printing and characterized these structures with X-ray microcomputed tomography. We compared the aerosol filtration performance of the different lattice unit cell geometries using 1 μm polystyrene latex (PSL) aerosol particles, finding the filtration performance to be positively correlated with the single-unit-cell specific surface area. We then expanded our evaluation of deposition efficiency in Kelvin cell lattice structures of varied porosities, again finding a correlation between the specific surface area and deposition performance. Experimental analysis confirmed that deposition primarily occurs through impaction and electrostatic mechanisms within the parameter space. Overall, our findings demonstrate that unit-cell-based lattices can achieve a wide range of aerosol filtration efficiencies (∼10–100%) across various operating conditions (1–4 m/s superficial velocity), offering a highly tunable in-line filtration medium capable of maintaining high efficiency even at elevated airflow rates. This work not only provides essential guidelines for designing and manufacturing 3D-printed lattices as customizable aerosol filters but also highlights the current limitations and challenges in producing these structures.

Adsorption of inert small molecules has always been challenging, and hence, these molecules are generally difficult to remove from solution. In this work, we demonstrated a significant improvement (>25 times) in the adsorption of an inert small molecule, urea, using a hierarchical material design, which remarkably outperformed the simple chemical functionalization of the substrate. To illustrate this point, we employed two-dimensional (2D) materials such as Ti₃C₂T_x MXene as the adsorbent “substrate” which has a high potential for efficient urea removal. In particular, Cu-functionalized MXene, with Cu valency between 0 and +1 exhibited superior urea adsorption performance compared to pristine MXene. However, due to the strong van der Waals forces, MXene has a propensity to aggregate, leading to the loss of active sites for urea adsorption. To address this, cellulose nanocrystals were introduced as they have dual functionalities, namely, to prevent aggregation and preserve active sites for adsorption of urea. These nanocrystals are small, rigid, and hydrophilic, facilitating their interaction with hydrophilic groups on the MXene surface. Porous hydrogel macrobeads prepared using alginate cross-linked with calcium ions yielded a hierarchical structure with nanosized MXene-cellulose moieties distributed within the millimeter beads. Besides serving as mechanical support, the cellulose nanocrystals can be further surface-functionalized with enhanced interaction with chemical groups such as polydopamine to boost the adsorption properties. Each component in the hydrogel composite synergistically enhanced the interaction with urea and promoted adsorption. Consequently, the composite hydrogel exhibited a remarkable enhancement in urea adsorption capacity from 6.7 to 354.4 mg/g in aqueous solution, while a maximum adsorption capacity (Q_max) of 115.1 mg/g was observed in simulated dialysate solution due to the increased surface area available for urea adsorption. The development of this hydrogel composite consisting of Cu-functionalized MXene, functionalized cellulose nanocrystals, and alginate cross-linked with calcium showcased its potential as a highly efficient and versatile material for effective urea adsorption in both aqueous and simulated dialysate solutions.

To investigate electrolyte/electrode interactions as a way to understand and improve the overall stability of bulk electrolytes, electrodes, and interfaces, soaking experiments were conducted on an earth-abundant cathode active material of 0.3Li₂MnO₃·0.7LiMn_0.5Ni_0.5O₂ (LMR-NM) as part of an effort for the Argonne-led Deep Dive Cathode Consortium through the Department of Energy. It was discovered that electrolyte additives featuring a tetracoordinated B^–-(OR)₂XY structure [including lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate, and other additives] function through a specific swapping mechanism with early-stage LiPF₆ decomposition. This mechanism, as evidenced by NMR, facilitates the formation of thermally stable salts of LiPF₄(OR)₂, which prevents further electrolyte degradation. LiDFOB was further proven to be an effective additive in mitigating transition-metal dissolution of LMR-NM caused by acidic electrolyte decomposition products etching during electrode soaking tests due to bulk electrolyte stabilization. Additionally, in an effort to improve the stability between electrolytes and electrodes, surface modified electrodes were also tested, showing that both Co doping (as well as bulk) and Al(NO₃)₃ coating can also mitigate these adverse electrode/electrolyte interactions. Density functional theory simulations reveal that Co can increase the formation energy of surface Mn vacancy defects on LMR-NM in the presence of H⁺ ions, thereby making dissolution more difficult.

As the demand for mobile electronic devices continues to grow, the development of all-solid-state lithium metal batteries has emerged as a promising solution to reduce the safety risks associated with conventional lithium-ion batteries. Herein, we introduce an approach to preparing a composite solid-state electrolyte by integrating two-dimensional (2D) MXenes with cationic covalent organic frameworks (cCOFs). These frameworks are based on ethidium bromide (EB-cCOF) and porphyrin (POR-cCOF), and are incorporated into the poly(ethylene oxide) (PEO)-based solid electrolytes. The synthesized MXenes and cCOFs serve as multifunctional additives, reducing the PEO crystallinity and enhancing segmental motion. We observed a synergistic effect when COFs and MXene were used in preparing electrolytes, highlighted in the observed increase in the ionic conductivity at room temperature. Additionally, the electrolyte exhibits improved thermal stability up to ≈380 °C and retains ≈9% more residual mass at 1000 °C. These results highlight the potential of hybrid solid electrolytes as promising candidates for advancing high-performance solid-state batteries.

Rational design and development of an acid–base multifunctional catalyst is a difficult task. Here, a multifunctional zirconium phosphate-based inorganic–organic hybrid catalyst (ZPCC), incorporating both acidic and basic sites, was synthesized by exfoliating α-ZrP and subsequently functionalizing it with 3-aminopropyltriethoxysilane (APTES) and cyanuric chloride. The as-synthesized catalyst exhibits outstanding catalytic performance for the transformation of carbon dioxide into cyclic carbonates with high selectivity using a low cocatalyst dose under solvent-free conditions. The catalyst ZPCC features Zr⁴⁺ and P–OH groups as acidic sites, and N-containing moieties [secondary amine (−NH−) and triazine ring (−C═N−)] impart basic nature to the catalyst. This combination of acid and base sites enacts a synergetic effect on the activation of epoxide and CO₂, respectively, and also increases the cocatalyst activity to open or close the epoxide ring. The functionalized catalyst, ZPCC, exhibited 50% conversion, 49% yield, and 95% selectivity toward cyclic carbonate without any cocatalyst, and it shows almost 100% conversion, 99% yield, and 99% selectivity at optimized conditions (including a minimal amount of cocatalyst and short reaction period). Nuclear magnetic resonance and GC–MS techniques were used to find a plausible mechanism and reveal the direct preparation of cyclic carbonates without any byproduct formation. The characterization of the used catalyst, easy recoverability, and the ability to be recycled over five times with more than 90% conversion demonstrate its ability to be used as a suitable catalyst for industrial purposes.

Label-free optical technologies have transformed cell culture monitoring, offering noninvasive alternatives that preserve cellular integrity─a critical factor in biomedical applications such as CAR T therapies and stem cell cultures. This review examines the current landscape of these technologies and their implementation at both laboratory and industrial scales. We highlight key techniques such as quantitative phase imaging, Raman spectroscopy, and autofluorescence imaging, among others, all of which enable multiparameter analysis without exogenous markers. In this direction, recent innovations in instrumentation and data analysis have facilitated the continuous acquisition of morphological and biochemical data from live samples, at both intra- and extracellular levels. These advances are driving the development of more automated, integrated, and unbiased processes that meet the evolving demands of modern cell bioprocesses. This review also emphasizes the collaborative efforts that are shaping label-free technologies in cell culture, bridging multiple disciplines. Additionally, it critically addresses current limitations of the field and explores future directions, particularly for the monitoring of in vitro cells in biomedical applications.

Carbon-based nanofibers are critical materials with broad applications in industries such as energy, filtration, and biomedical devices. Polyacrylonitrile (PAN) is a primary precursor for carbon nanofibers, but conventional electrospinning techniques typically operate at low production rates of 0.1-1 mL/h from a single spinneret, limiting scalability. In this study, we introduce a novel liquid-assisted ultrahigh-speed electrospinning (LAUHS-ES) technique that achieved actual production rates over 220 times faster than conventional methods. This dramatic increase in throughput is achieved through Taylor cone stabilization using a thin layer of liquid sheath, allowing for ultrahigh-speed electrospinning without compromising the structural integrity or uniformity of the nanofibers. Comprehensive characterization, including scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), confirmed the high quality, consistency, and crystallinity of the produced nanofibers. Our results demonstrate that PAN nanofiber fabrication can be scaled up significantly while maintaining precise control over fiber morphology and performance. This advancement holds substantial promise for large-scale industrial applications, enabling more efficient and cost-effective production of carbon-based nanofibers.