ACS Applied Nano Materials最新文献

Chemical pollution poses a major threat to environmental and human health, necessitating efficient remediation strategies. Photocatalysis offers a promising approach, yet its effectiveness is often limited by charge recombination and surface reactivity. Here, we investigate aliovalent doping of strontium titanate (SrTiO₃) with aluminum to enhance photocatalytic degradation of organic pollutants, including the anionic dye methyl orange and the chlorinated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D). SrTiO₃ nanoparticles were synthesized via solid-state reaction and subjected to flux-mediated Al doping (0–20 mol %). High-resolution electron microscopy revealed a previously unreported Al-enriched surface layer at high doping levels (>5 mol %), which correlates with reduced photocatalytic activity. The highest degradation rate was observed for nominally undoped samples (0 mol % Al, sourced from the crucible), suggesting surface Al accumulation inhibits charge migration and pollutant adsorption. Scavenger experiments identified superoxide anions as key reactive species. Furthermore, C–Cl bond cleavage in 2,4-D confirms the material’s potential for remediating persistent organic pollutants. These findings provide mechanistic insight into dopant distribution and surface effects, guiding future design of photocatalysts for environmental applications.

Inspired by the remarkable sensitivity of spider slit organs, nanostructured strain sensors based on the controlled formation of micro/nanocracks offer promising solutions for applications in tactile sensing, electronic skin, and physiological monitoring. However, existing crack-based strain sensors often struggle to simultaneously achieve low detection limits, wide linear ranges, fast response, and long-term durability. This bottleneck arises from the fundamental trade-off between the large expansion of microcracks required for high signal modulation and the elastic recovery necessary for cyclic stability. Here, we developed a trinanomaterial Au/graphene–CNT (AGC) strain sensor by integrating a nanogold (Au) layer with a graphene–carbon nanotube (Gr–CNT) composite layer. The brittle Au nanolayer generates a dynamic microcrack network that enhances mechanical sensitivity during deformation, while the ductile Gr–CNT layer maintains electrical conductivity under large strains. Leveraging this strategy, the fabricated AGC strain sensor exhibits exceptional sensing performance: an ultralow detection limit (<0.01% strain), wide sensing range (0–35%), rapid response time (4.3 ms), and excellent long-term durability (>20,000 cycles). These combined capabilities make it highly versatile, enabling applications ranging from the real-time detection of subtle physiological signals and human joint movements to gesture recognition and high-frequency fatigue monitoring in structural materials.

Solar-blind ultraviolet (UV) photodetectors are critically important for applications such as flame sensing, missile warning, and space communications. These applications exploit the solar-blind background in the near-earth atmosphere, where the ozone layer strongly absorbs solar UV-C radiation (200–280 nm), creating an environment with inherently low background noise. To achieve high-performance detection under such weak signal conditions, we present a self-powered detector architecture based on a band-offset engineered n–n heterojunction. The device was fabricated by directly growing a network of Sn-doped Ga₂O₃ nanowires on a GaN substrate via chemical vapor deposition (CVD), forming a heterostructure with patterned electrodes. Under 254 nm illumination (82 μW/cm²), the device demonstrates exceptional performance: a photocurrent of 14.57 μA, a responsivity of 5.66A/W, an external quantum efficiency (EQE) of 2762%, and a high photo-to-dark current ratio (PDCR) of 8830. Moreover, the detector exhibits a specific detectivity (D*) of 4.36 × 10¹³ Jones, a fast response time below 50 ms, an ultralow dark current of 1.65 nA, and excellent operational stability. The superior performance is attributed to two key design features: the favorable band alignment at the GaN/Sn:Ga₂O₃ interface, which promotes efficient carrier separation through a strong built-in electric field originating from the large conduction band offset (ΔE_c ≈ 1.36 eV), and the light-trapping effect of the nanowire network architecture, which enhances photon absorption. The powerful built-in electric field further enables effective self-powered operation without external bias, making this architecture highly suitable for low-power and portable solar-blind detection systems.

Herein, we report a simple and rapid method for the synthesis of DNA–gold nanoparticle conjugates (DNA-AuNPs) relying on the mechanism of DNA extraction. By the addition of ethanol and NaCl to the mixture of DNA and AuNPs, charge-neutralized DNA strands are instantaneously decorated on AuNPs to form DNA-AuNPs. Meanwhile, the as-formed DNA-AuNPs are promptly salted and aggregated to facilitate subsequent rapid separation. The whole process requires no special reagents or instruments and can be easily completed in a few minutes. The prepared DNA-AuNPs exhibit high stability and are hybridizable. The proposed method simultaneously satisfies the demands of simplicity, rapidity, high DNA grafting density, scalability, and generality. This study provides an advanced strategy for the efficient synthesis of DNA-AuNPs for subsequent applications.

African swine fever virus (ASFV) poses a severe threat to the global swine industry, demanding rapid on-site diagnostics due to the lack of an effective vaccine. Existing laboratory-based methods, such as PCR and ELISA, are limited by cost, complexity, and infrastructure requirements, hindering their use in resource-limited settings. Colorimetric assays offer a promising alternative for instrument-free, rapid detection, but conventional reliance on fragile and expensive natural enzymes such as horseradish peroxidase (HRP) is problematic. This research addresses this need by developing a highly sensitive colorimetric sensor for ASFV based on a two-dimensional (2D) MoSe₂@Fe-MOF nanozyme. This composite nanozyme leverages a synergistic effect: Fe-MOF provides abundant peroxidase-like (POD-like) active sites, while integrated MoSe₂, a p-type semiconductor, enhances charge transfer at the heterojunction. This synergy boosts the catalytic oxidation of the chromogenic substrate TMB, resulting in a vibrant blue color signal (the “ON” state). To achieve specific ASFV detection, the nanozyme surface is functionalized with antibodies targeting the p72 major capsid protein. Upon capturing ASFV, the resulting immuno-complex generates significant steric hindrance, physically blocking catalytic sites and impeding substrate access. This inhibition significantly reduces TMB oxidation, leading to a decrease in color development and absorbance (the “OFF” state). This efficient signal modulation enables the sensor to achieve a remarkably low limit of detection of 0.22 TCID₅₀/mL in just 15 min, offering a rapid, cost-effective, and reliable solution for on-site ASFV diagnostics.

Nanostructured silver-exchanged zeolites (Ag⁺-exchanged zeolites) have been widely studied for ethylene (C₂H₄) removal from space and for separation from mixtures. However, the controlled release of C₂H₄ from Ag⁺-exchanged zeolites has received little attention. In this study, we propose a novel application of Ag⁺-zeolite X as a slow C₂H₄-releasing nanoporous material to suppress potato sprouting. The adsorption and release behaviors of C₂H₄ over a series of Ag⁺-exchanged zeolites with different zeolite framework topologies and Ag loadings were systematically investigated. The characteristics of the zeolites significantly influenced the nature of the introduced Ag species, which in turn affected the adsorption and release behavior of C₂H₄. In zeolites with high Ag loadings, Ag species tend to aggregate into large Ag clusters or metallic Ag⁰ nanoparticles, which do not work as C₂H₄ binding sites. Among the Ag⁺-exchanged zeolites studied, Ag₃₆-X, which is zeolite X with a silver ion-exchange rate of 36%, showed high C₂H₄ adsorption capacities and sustained C₂H₄ release characteristics. The application of Ag₃₆-X in potato packaging demonstrated superior sprout inhibition performance compared to a commercial C₂H₄ release agent, highlighting the potential of Ag-loaded zeolites as tunable C₂H₄ release nanoporous materials for postharvest applications.

Magnesium (Mg)–air batteries are regarded as promising large-scale energy-storage devices because of their high theoretical energy density, low material cost, intrinsic safety, and environmental benignity. Nevertheless, their practical deployment is severely hindered by sluggish oxygen reduction reaction (ORR) kinetics at the cathode. Herein, nanoscale transition-metal–nitrogen-doped carbon (M-N-C, M = Fe, Co, Ni) electrocatalysts─denoted FNC, CNC, and NNC─are prepared by argon-pyrolysis of Prussian blue analogues (PBAs). The cationic and anionic ligands are systematically varied to tailor the crystal phase, pore architecture, and nanoscale M-N_x coordination environment. Comprehensive characterization shows that CNC possesses the highest density of well-dispersed Co-N_x active nanosites embedded in a graphitic matrix. This ensures rapid electron transfer and abundant accessible active centers. Electrochemical tests in alkaline (0.1 M KOH) and neutral (3.5 wt % NaCl) electrolytes demonstrate that CNC delivers the most robust ORR activity and stability (CNC > FNC > NNC) via a near-ideal 4 e pathway. Meanwhile, CNC exhibits better stability than commercial Pt/C in both alkaline and neutral electrolytes. As the cathode nanocatalyst in Mg-air batteries, CNC is found to yield a peak power density of 19.14 mW/cm²─only 0.66 mW/cm² below that of commercial Pt/C. The decisive role of nanoscale M-N_x coordination environments in boosting ORR kinetics is thus elucidated. This work provides a nanomaterials-driven strategy for developing high-performance, cost-effective electrocatalysts for Mg-air batteries.

Two-dimensional transition metal dichalcogenides (TMDCs), such as MX₂ (M = Mo, W; X = S, Se), have emerged as promising materials for optoelectronic applications owing to their high carrier mobility and the transition from an indirect to a direct band gap at the monolayer limit. Among them, monolayer WS₂ is particularly attractive; however, films grown by chemical vapor deposition (CVD) commonly exhibit weak and spatially nonuniform photoluminescence (PL) because of intrinsic surface defects. In this work, monolayer WS₂ was synthesized via a bottom-up CVD process using a three-zone furnace, producing well-defined triangular crystals with average lateral dimensions of ∼20–25 μm and a maximum size of ∼75 μm. To improve its light-emission performance, surface defect passivation using H₂SO₄ vapor was systematically explored. Comprehensive structural, morphological, and chemical characterization using AFM, SEM, EDX, Raman spectroscopy, and XPS confirmed the formation of high-quality monolayer WS₂ and provided insight into the chemical modifications induced by the vapor treatment. Room-temperature PL measurements show that pristine WS₂ exhibits a sharp yet weak emission centered near 626 nm. After H₂SO₄ vapor exposure, the PL intensity increases by up to 20-fold, accompanied by a red shift of the emission peak to ∼634 nm. Deconvolution of the PL spectra reveals a pronounced suppression of trion emission and a corresponding enhancement of neutral exciton recombination. Consistent with these observations, first-principles calculations indicate that oxidation-driven passivation of sulfur vacancies eliminates mid-gap defect states and induces band gap renormalization. Overall, this study demonstrates, for the first time, the effectiveness of H₂SO₄ vapor passivation for WS₂ monolayers and introduces a simple, scalable, and relatively mild strategy for enhancing excitonic purity and radiative efficiency under ambient conditions. These findings strengthen the potential of monolayer WS₂ as an optically active material for photoelectric conversion, where reduced nonradiative recombination and improved optical quality are critical.

Phototheranostics, which combine light-induced therapeutic and diagnostic modalities in a single platform, is a novel approach in tumor treatment and diagnostics. The development of dual-action nanomaterials with photothermal activity and the ability to act as photoactivated chemotherapy, capable of the light-induced release of chemotherapeutic agents, is a challenging task. However, different nanosystems reported to date represent either photoactivated chemotherapy (PACT), agents of photothermal therapy (PTT), or the loading of a drug and photoabsorber in a single polymer carrier. Herein, we report a near-infrared-light-activatable theranostic nanoplatform CF₃-Pt-NPs with dual antitumor action, PTT/PACT, which is also capable of fluorescent and photothermal imaging of tumor tissues, based on the photoactivated Pt(IV) prodrug CF₃-Pt with BODIPY in the axial position. A barrier-free CF₃ rotor moiety in the BODIPY core provides excellent photothermal efficacy for the nanoplatform, while both the Pt(IV) prodrug CF₃-Pt and nanoparticles CF₃-Pt-NPs based on it act as PACT agents by releasing cisplatin under 740 nm light irradiation. Metabolomic profiles of CF₃-Pt-NP-treated MCF-7 cells confirmed strong thermal- and cisplatin-induced responses of cells. CF₃-Pt-NPs demonstrated the ability to accumulate in vivo in tumors, with the degree of fluorescence in the tumor correlating well with platinum accumulation, thereby confirming the ability of CF₃-Pt-NPs to reach the tumor intact. A strong photothermal effect in vivo was confirmed after both intratumoral and intravenous administration of CF₃-Pt-NPs with 808 nm laser irradiation. This is the first theranostic nanoplatform with dual PTT/PACT antitumor action, which is also capable of fluorescent and photothermal imaging of tumor tissues.

Ultrafast lasers have extensive and important applications in precision processing, biomedicine, ultrafast spectroscopy research, and communication fields. Saturable absorber materials are key components in obtaining ultrafast lasers. However, at high mode-locked pump power, the saturable absorber is easily damaged, greatly reducing its operational stability and service life. Here, we report the synthesis of uniform tellurium quantum dots with an average size of ∼3 nm and stable traditional soliton mode-locked fiber laser achieved at an extremely low pump power of 30 mW, with an output pulse width of 700 fs based on the tellurium quantum dot saturable absorber. As the pump power further increased, the output pulse width was compressed to 578 fs at 150 mW. Even more interestingly, by adjusting the pump power, the phenomenon of bound soliton mode-locked was also discovered. The experimental results demonstrate that the synthesized uniform tellurium quantum dots exhibit an ultralow mode-locked threshold, enabling ultrafast laser operation at low pump powers. This material represents a promising saturable absorber with unique application potential.