ACS Applied Nano Materials最新文献

With the rapid development of information technology, people’s demand for intelligent, convenient, and comfortable electronic devices is gradually increasing, and flexible intelligent wearable electronic devices are leading the development trend of the future intelligent industry. As an important part of noncontact sensing, humidity sensing plays an important role in flexible wearable electronic devices. In this paper, by combining conductive multiwalled carbon nanotubes (MWCNTs) and silver nanowires (AgNFs) with sodium alginate (SA), the AgNFs/MWCNT/SA humidity sensing fibers with excellent sensitivity and stability were prepared by the simple wet spinning method. Experimental results show that the humidity sensing fiber had a large relative resistance change over a wide humidity range of 10–90%, and it can be sensitive to the humidity difference of 5% in the high humidity limit. In addition, the change in fiber diameter and AgNF content would affect the sensing performance of the humidity sensor fibers. Finally, the humidity sensing fiber with a diameter of 156 μm and a AgNFs content of 3.3 wt % was selected and woven into the mask and textile, which successfully realized the monitoring function of respiratory function and the skin surface moisture volatilization process. The successful preparation of the AgNFs/MWCNT/SA humidity sensor fiber broke through the shortcomings of traditional humidity sensing materials, such as poor flexibility, a complex preparation process, and the inability to realize fabric-based wearable devices through the weaving process, and provided unlimited possibilities for the development of smart wearable devices.

The development of economical, high-efficiency synthesis approaches is the primary field of concern for research on microwave-absorbing materials (MAMs). In this work, we used the hydrothermal approach to effectively manufacture CeO₂ nanoparticles/porous carbon composites enriched with oxygen vacancies under urea-assisted conditions. The carbon source for these composites was the porous carbon generated from bamboo powders. We adjusted the electromagnetic characteristics of the composites to optimize their electromagnetic wave (EMW) attenuation mechanisms and impedance matching properties by altering the heat treatment temperatures and the extra quantity of cerium salts. The creation of many defects and heterostructures as a result of the nitrogen/oxygen doping and oxygen vacancy-rich CeO₂ leads to better EMW attenuation, conductivity loss, and increased polarization effects. The remarkable microwave absorption ability of the C2-500 composite is attributed to good impedance matching and interfacial polarization as well as dipole polarization induced by a significant number of heterogeneous interfaces and oxygen vacancies, particularly from N/O heterogeneous elements. At a filler loading of 10 wt %, C2-500 exhibits a minimum reflection loss (RL_min) of −44.94 dB at 16.16 GHz, accompanied by an effective absorption bandwidth (EAB) of 4.72 GHz. In comparison, the C3-500 composites demonstrate an EAB of 4.88 GHz and an RL_min of −46.81 dB at 9.28 GHz. This study is expected to be instrumental in the design of high-performance biomass-derived porous carbon-based MAMs, providing valuable insights for future research in this field.

Current-induced spin–orbit torque (SOT) in heavy metal/ferromagnets can be used to manipulate the magnetization and electronic transport properties for logic and memory operations. Significantly, Fe₄N shows an in-plane magnetic anisotropy at larger thicknesses but enters a noncollinear magnetic phase at suitably nanoscale thicknesses. Here, the electronic transport properties of Pt(3 nm)/Fe₄N(t_Fe4N ≤ 6 nm)/MgO(sub)structures were investigated. Current-driven anomalous Hall resistivity ρ_AHE changes appear due to SOT. Moreover, sign reversal of Hall resistivity ρ_xy occurs due to the competition between the magnetic proximity effect and inverse spin Hall effect. A model based on the above contributions was built to demonstrate how torque changes with increasing charge current and why sign reversal of ρ_xy occurs.

There is a continuous vivid search for biocompatible hybrid magneto-optical nanoprobes with high heating and photoluminescence efficiencies for photothermal theranostics. Herein, two tailored multipurpose hybrid PEGylated gold (Au) and silver sulfide (Ag₂S) magnetic iron oxide nanoparticle formulations (Au-PEG-MNPs and Ag₂S-PEG-MNPs) with unique opto-magnetic properties for simultaneous photothermal therapy were prepared. The physiochemical properties of the hybrid MNPs were fully characterized using various electronic and spectroscopic techniques, showing colloidal stabilized small-sized nanoparticles (core sizes = 10 nm, D_H = 200 nm) with high saturation magnetizations (M_s up to 85 emu/g) and superparamagnetic behavior. Thermal effects in response to an alternating magnetic field (AMF) at different frequencies (f = 25–300 kHz) and field intensities (H = 12 and 24 kA/m) were assessed using an ultrafast magnetometric method, revealing high heating efficiencies with distinctive heating responses. The “optothermal” efficacies were then evaluated using a unique experimental setup equipped with a highly sensitive thermal camera for recording temperatures in real time, along with a simultaneous clinically safe near-infrared (NIR) laser (λ = 808 nm and power = 0.5 W cm^–2) and AMF (H = 12 kA/m, f = 180 kHz) dual effect. Remarkably, when irradiated with an NIR laser and AMF, both hybrid Au- and Ag₂S-PEG-MNPs displayed superior heat induction power (SAR = 384 and 441 W/g), rapidly reaching hyperthermia temperatures of 42 °C in only a few seconds. Temperatures could reach up to 75 °C for Au-PEG-MNPs and 90 °C for Ag₂S-PEG-MNPs in only 5 min. Such superior heating efficiencies for the hybrid MNPs increased ∼1.5–2 times under concurrent irradiation compared to the action by laser alone. Finally, cytotoxicity assays against cancerous and normal cells confirmed the safety profiles and low toxicities of the hybrid nanoformulations. This unique synergistic platform has great potential to be utilized for multimodal photothermal therapy with reduced field strengths, laser intensities, and short irradiation times in the unceasing search for tangible hyperthermal clinical nanoprobes.

A highly functioning copper cobalt-based ternary phosphide (CCP) cathode was engineered from a copper cobalt carbonate hydroxide (CCH) material via a gas–solid thermal route, resulting in a 3D spatial morphology with a hierarchical architecture and porosity. Preliminary electrochemical testing revealed the superiority of the CCP cathode with a specific capacity value of 2392 C g^–1 at 10 A g^–1 and a capacity retention of 94.4% over 5000 cycles at 40 A g^–1. The morphological advantages of CCP with its 3D hierarchical architecture, highly porous network, and numerous nanospikes with sharp edges and surface defects offer tremendous active sites and ion transport channels for better charge storage performance. The CCP//activated carbon electrode (ACE) hybrid supercapacitor (HSC) device delivered a capacity value of 284.5 C g^–1 at 10 A g^–1 and a 92.3% retention in capacity for 10 000 cycles at a high current density of 30 A g^–1. Furthermore, the fabricated device provided high energy and power density values of 129.15 Wh kg^–1 and 66.4 kW kg^–1, respectively, and powered a red LED for 1 min. Thus, this work efficiently provides knowledge on the development of a Cu₃P–CoP electrode material from optimizing morphological features and synthetic routes, which leads to achieving superior functioning cathode materials for hybrid supercapacitors in the current energy storage era.

Electrocatalytic reduction of nitrate (NO₃RR) to ammonia offers a promising approach for mitigating the environmental impact of NO₃^–, while simultaneously enabling the synthesis of NH₃ under ambient conditions. Recently, single-atom catalysts (SACs) have been proven to have attractive activity on NO₃RR, and better catalysts with enhanced activity and stability are still in demand. Here, we report the efficient boosting of NH₃ production via the NO₃RR using boron-doped Fe SAC (Fe-BCN). Fe-BCN is a normal 12-hedral nanoparticle with a size of 500 nm. The NH₃ Faradaic efficiency of Fe-BCN reached 97.48%, with a high ammonia production rate of 2.17 mg cm^–2 h^–1, in an alkaline electrolyte environment at an electrode potential of −0.3 V vs reversible hydrogen electrode. Density functional theory calculations revealed the strategy of introduced B regulating the intermediate adsorption on Fe-BCN, which enhanced the NO₃RR activity. Furthermore, leveraging the high NO₃RR activity of Fe-BCN, a nitrate-zinc battery with a power density of 0.90 mW cm^–2 was constructed by using Fe-BCN as the cathode and zinc as the anode, respectively. This research demonstrates the broad prospects of Fe-BCN in the NO₃RR and provides insights for high-performance Fe SAC electrode materials.

The triboelectric nanogenerator (TENG) is an emerging technology to convert energy for powering electrical devices. Extensive strategies have been studied to enhance the output performance of TENG. Herein, nanopillar- and nanocone-structured SrTiO₃ (STO)/PDMS composite films with different STO concentrations were fabricated as the dielectric layer. The effects of the morphologies of nanostructured composite films produced by the anodic aluminum oxide (AAO) template method on the dielectric and electric properties of the TENG were investigated. The dielectric constant of the structured composite film increased with the concentration of STO nanoparticles and is negligible depending on the frequency from 10² to 10⁶ Hz. The 9 wt % STO/PDMS composite film with a nanocone structure (aspect ratio = 3) shows the highest dielectric constant value at 4.85. The dielectric loss of nanostructured composite films is steady at 0.01 from 1 × 10³ to 1 × 10⁶ Hz. In addition, the electrical performance of TENG with the nanocone-structured composite films is greater than the nanopillar structure based, and the electric properties are promoted with the nanostructure aspect ratio. Meanwhile, the increased STO concentrations of the composite film significantly enhanced the electric properties of TENG as well. The Voc and Isc of TENG reached about 130 V and 1.4 μA with 9 wt % STO/PDMS nanocone-structured (aspect ratio = 3) composite film. Furthermore, the output voltage and charge density of various nanostructured films were numerically calculated using the Finite Element Method (FEM) in COMSOL Multiphysics, which shows good agreement with the experimental results. Finally, the fabricated TENG device was utilized to power the commercial LEDs and electric devices successfully. As the ideal self-powered sensing device, the portable and functional TENG shows attractive potential of application in the field of self-powered sensing systems and flexible devices.

Herein, garlic oil-functionalized onion-like carbon (OLC) nanoparticles were successfully prepared through a multistep process involving the carbonization of candle ash followed by surface modification. Initially, the OLC was prepared by heat-treating candle ash under 450 °C and then grafting polyethylenimine (PEI) using epigallocatechin gallate (EGCG) as a cross-linking agent. Subsequently, garlic oil was grafted onto PEI@OLC via the aza-Michael reaction with PEI, thereby obtaining garlic oil-functionalized OLC nanoparticles (GO@OLC). The GO@OLC exhibited enhanced lubrication properties as a lube additive, with a low coefficient of friction (COF) of 0.11 and a significant reduction of 76.57% in wear volume. The enhanced lubrication performance is credited to the rolling effect and surface repairing effect of the OLC nanoparticles as well as the formation of a complex protective layer by GO@OLC-induced tribochemical reactions.

Composites of nanocarbons and transition metal oxides combine excellent mechanical properties and high electrical conductivity with high capacitive active sites. These composites are promising for applications such as electrochemical energy conversion and storage, catalysis, and sensing. Here, we show that Joule heating can be used as a rapid out-of-oven thermal processing technique to crystallize the inorganic metal oxide matrix within a carbon nanotube fabric (CNTf) composite. We choose manganese oxide and vanadium oxide as model metal oxides and show that the Joule heating process is rapid and enables accurate control over the temperature and phase transitions. Next, we use thermogravimetric analysis and Joule heating experiments in controlled atmospheres to show that metal oxides can actually catalyze thermal degradation and reduce the thermal stability of the CNTs, which could limit processing of many oxides. We solve this by using a reducing hydrogen atmosphere to successfully extend the Joule processing window and thermal stability of the CNTf/metal oxide composite to ∼1000 °C.

Hybrid systems encompassing plasmonic silver nanoprisms (AgPRs) and efficient catalysts such as platinum (Pt) offer tremendous opportunities in advancing plasmonic chemistry toward environmentally sustainable chemical transformations. Galvanic replacement reactions (GRRs) offer a simple and versatile route to preparing such hybrid systems. Syntheses of Ag–Pt hybrids via GRRs have previously employed various platinum salts that appear to face a thermodynamic barrier while reacting with a Ag crystal. This work carefully reinvestigates the reaction between AgPRs and [PtCl₄]^2– ions and identifies the important role that crystal facets and the instability of reactant molecules can play in overcoming the uphill barrier, thus allowing the reaction to proceed to at least some extent. To overcome the poor efficiency of this reaction, the work introduces a photodriven pathway that allows control over the synthesis of Pt-coated AgPRs. Photon energy plays a role in controlling the reaction kinetics and dictating the extent to which this reaction could be enhanced, while the plasmonic modulation allows spatial biasing of the reaction kinetics at specific subsites of the AgPRs. The findings presented here enrich our mechanistic understanding of plasmon-enhanced chemical reactions, thus, expediting opportunities to deploy plasmonic chemistry for industrially important chemical transformations.