ACS Applied Nano Materials最新文献

This study presents Materials Institute Lavoisier (MIL)-101(Cr) metal–organic framework (MOF) nanoparticles used for the detection of 6-kDa early secreted antigenic target (ESAT-6) and 10-kDa culture filtrate protein (CFP-10) biomarkers from the Mycobacterium tuberculosis complex (MTBC). The presence of CFP-10 and its fragment D7-F100 CFP-10, ESAT-6, and its variant ESAT-6*, along with their doubly charged peaks below 6 kDa, were detected using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with MIL-101(Cr) MOF nanoparticles. The mass peaks (mass-to-charge ratio, m/z) observed at approximately 10100 and 10660 correspond to CFP-10, while those at 7931, 7974, 9750, and 9796 correspond to ESAT-6. The adsorption of tuberculosis (TB) biomarkers by MIL-101(Cr) nanoparticles was primarily driven by electrostatic interaction, hydrogen bonding, and functional group binding, enabling selective protein enrichment. Their high surface area and pore volume provide accessible adsorption sites for TB-specific proteins. The sensitivity and specificity of MTBC samples reached 94.3 and 100%, respectively, and no TB biomarkers were detected in nontuberculous Mycobacteria (NTM) samples, indicating that these biomarkers effectively distinguish MTBC from NTM. This study featured a qualitative analysis MOF-based MALDI-TOF MS platform, which developed a robust and scalable alternative to the diamond nanoparticle platform. Overall, MALDI-TOF MS combined with MIL-101(Cr) nanoparticles offers a promising approach for improving TB biomarker detection, leading to more efficient and reliable strategies for TB detection.

The electrochemical reduction of CO₂ (CO₂RR) into hydrocarbons has emerged as a promising strategy for sustainable energy conversion and carbon neutrality. Among the various possible products, CH₄ is of particular interest because it can be directly used in existing infrastructure, unlike H₂ and NH₃. However, despite intensive studies, the intrinsic role of Cu catalyst size in CH₄ selectivity has remained unclear due to the complex interplay between particle size, morphology, exposed crystal planes, oxidation states, and defect structures. In this work, we aimed to clarify the size effect in the CH₄-selective CO₂RR by preparing single-layer Cu nanosheets (SLCs). By electrostatically adsorbing Cu²⁺ ions onto titanate nanosheets followed by electrochemical reduction, SLCs with an atomic thickness were synthesized, and their lateral dimensions were tuned by adjusting Cu²⁺ loading. Structural characterization confirmed that SLCs maintained single atomic layers of 0.3 nm at Cu²⁺ loadings of 1.6–7.6 wt %, whereas larger loadings resulted in multilayer Cu (MLCs) at loadings of 7.6–11.7 wt %. CH₄ Faradaic efficiency showed a volcano-type dependence on SLC diameter, peaking at 39%. In contrast, H₂ selectivity followed an inverse volcano trend. Mechanistic analysis revealed that CH₄ selectivity correlates with the fraction of in-plane Cu atoms, whereas H₂ selectivity correlates with the edge Cu atoms. These findings establish the intrinsic size–selectivity relationship in two-dimensional Cu catalysts and provide a strategy for designing oxide-supported single-layer catalysts to optimize CH₄ production in the CO₂RR.

Considering the abundance and pollution-free nature of solar energy, it is necessary to design photothermal catalysts to obtain high-value chemicals driven by the endothermic catalytic reaction. Herein, PC-1/PmPD and PC-2/PmPD with hierarchical nanostructure assembled from nanosheet arrays are fabricated by phase transition from metastable precursor metal–organic frameworks (MOFs) under the stimulation of methanol and m-phenylenediamine (mPD). This phase transition involves dissolution-recrystallization and polymerization in one step, which not only completes precise morphology transformation but also attaches functional polymer in the composites. Owing to the photothermal effect and catalytic activity provided by the poly(m-phenylenediamine) (PmPD) and hierarchical nanostructures, such as abundant optical traps and more exposed active sites on the outer surface, PC-1/PmPD and PC-2/PmPD achieve efficient photothermal catalytic activity in the cycloaddition reaction of carbon dioxide driven by simulated sunlight at room temperature. The construction of hierarchical MOFs/polymer composites with nanosheet arrays as photothermal catalysts may open opportunities to expand their diversity and range of potential applications.

Lightweight polymer-derived ceramics offer exceptional thermal and chemical stability but exhibit limited performance in electromagnetic wave (EMW) absorption due to low dielectric loss. This study presents a layered β-SiC/SiOC nanocomposite architecture fabricated via direct ink writing (DIW), with carbon nanotubes (CNTs) spatially confined to the central layer. β-SiC functioned as a rheology modifier, making the inks DIW-printable, while simultaneously enhancing dielectric loss. CNTs contributed to improved conductivity and interfacial polarization losses. The three-layer design, with porous β-SiC/SiOC top and bottom layers, allows EMW penetration and reduces surface reflections, while the CNTs in the middle layer promote internal reflections and prolong EMW interaction within the absorber. Transmission electron microscopy revealed core–shell-like CNT-SiOC interfaces, highlighting the role of interfacial polarization in energy dissipation. Among the sample compositions tested (samples with 0, 1, and 2 wt % CNT content), the intermediate CNT content (CNT-1) exhibited the highest performance, achieving a minimal reflection loss of −59.47 dB at a thickness of 3.39 mm, maximum effective absorption bandwidth covering ∼88% of the X-band, and high absorption efficiency per unit thickness (EAB_max/d ∼1.16 GHz/mm). The CNT-1 also demonstrated superior compressive strength (∼1.46 MPa), nearly double that of the CNT-free composite. However, excessive CNT loading (CNT-2) led to agglomeration and reduced performance. These findings demonstrate that controlled filler distribution and architectural design enable lightweight, thin, and broadband EMW absorbers, providing a versatile strategy for next-generation functional ceramics.

High-quality, multifunctional two-dimensional (2D) titanium oxynitide (TiNO) thin films and one-dimensional (1D) TiNO nanowires have been synthesized using a pulsed laser deposition, a simple, fast, and congruent evaporation method. First-principles calculations as a function of surface orientation and termination indicate that surface oxidation of TiNO nanowires can stabilize the (110) orientation observed experimentally. The specific capacitance value for the TiNO nanowire samples (2725 mF/cm²) has been found to be nearly six times more than that of the TiNO thin film samples (400 mF/cm²), which is attributed to the high packing density of TiNO nanowires over a given area. The nanowire samples have also been found to exhibit a significantly higher energy density (1.35 μWh/cm²) than the TiNO thin-film samples (0.33 μWh/cm²). Thus, the TiNO material system in thin-film and nanowire forms has been demonstrated to be a promising candidate for use as an electrode material in supercapacitors and other charge-storage applications.

Serotonin is one of the crucial neurotransmitters that plays a vital role in human physiology and normally exists in human serum in the 200 nM to 1.1 μM range along with a wide variety of interfering agents. This makes it a quite challenging task to detect serotonin in an efficient, electrochemical way at ambient temperature in a relatively low concentration (nanomolar) of abundance. So, this work is focused on developing an enzyme-less electrochemical sensing platform that can detect serotonin with a very low limit of detection (LOD) in a highly sensitive and selective way. For this purpose, carbon quantum dots (CQDs), one of the advanced carbonaceous materials, were prepared from a natural source (corn seeds) and applied to make a nanocomposite sensing platform with an electrochemically deposited NiWO₄ thin film on FTO-coated glass substrate. The prepared materials were thoroughly characterized by using sophisticated instrumentation techniques. The fabricated NiWO₄/CQD nanocomposite thin film was then subjected to detailed electrochemical probing toward serotonin sensing. Fascinatingly, the developed sensor prototype yielded an LOD of 134.0 nM without compromising the sensitivity (16.9 μA μM^–1 cm^–2), which makes it well capable for detecting serotonin that is present in human serum in the nM to μM order.

Molybdenum disulfide (MoS₂) possesses excellent light–matter interaction intriguing for electronics and optoelectronics applications. However, precise MoS₂ fabrication poses major challenges demanding high-temperature inert furnaces alongside the time-consuming process. Femtosecond (fs) laser fabricates with high precision owing to shorter (10^–15 s) pulses inhibit heat transfer to vicinity. 0.25 and 0.5 molar ratios are more suitable for MoS₂ fabrication, and the structural characteristics confirm the successful fabrication of fs laser-patterned MoS₂ in the 2H bulk phase. The wettability analysis manifests good hydrophilic behavior suitable for heterostructure fabrications. Thermogravimetric analysis and systematic annealing from 200 to 400 °C performed for 0.5 M of MoS₂ reveals good thermal stability until 250 °C. The chemical stability was analyzed by immersing the 0.5 M sample for 5 days in pH-3 (HCL/H₂SO₄), which holds better stability than the pH-10 (NaOH) sample, leading to chemical modifications. The optical absorption examined using UV–visible DRS shows the characteristics of MoS₂. The chemically modified pH-10 (NaOH) (CM-MoS₂) sample exhibits the characteristics of MoO₃ and MoS₂ peaks which display enhanced absorption. It shows excellent photoluminescence (PL) emission by altering the negative trions recombination to excitons yielding a high PL quantum yield. The third-order nonlinear optical absorption investigations on ITO and 0.25 M MoS₂ samples reveal saturable absorption (SA) behavior. The 0.5 M and CM-MoS₂ samples show reverse saturable absorption behavior favoring optical limiting applications.

Copper-based electrocatalysts have attracted significant attention for the electrochemical reduction of CO₂ into value-added chemicals, such as ethanol. However, their practical application is limited by poor selectivity and stability under operating conditions along with the low faradaic efficiency. In this work, we demonstrate enhanced CO₂RR performance through surface restructuring and local microenvironment manipulation via defect engineering. A controlled thermal annealing process was employed to induce hydrophobic microchannels within nanoporous copper oxide, thereby promoting the selective reduction of CO₂ to ethanol. CO-TPD and water contact angle measurements confirmed that the sample with the highest hydrophobicity exhibited superior CO₂RR activity, which remained stable under long-term chronoamperometry. The optimized catalyst achieved exceptional selectivity toward ethanol production, delivering a maximum yield of 10.05 mmol cm^–2 h^–1 g^–1 at −1 V (vs RHE), with a faradaic efficiency of 41% of ethanol production. Postcatalytic characterization revealed that both the microstructure and hydrophobicity were preserved along with the changes in the oxidation state as a result of the applied reduction potential. This work demonstrates a strategic manipulation of the microenvironment to improve faradaic efficiency of a solid–liquid–gas interfacial electron transfer reaction.

Recently, numerous researchers have overcome the insufficient energy density of metal oxides in energy storage applications by tailoring their dimensions to the quantum dot scale and integrating them with carbon-based matrices. In this work, Hf₆Ta₂O₁₇ quantum dots (HTO-QDs) were synthesized in situ on the surface of biomass-derived carbon nanospheres (CNS) via a polymer-derived ceramic method, resulting in CNS@HTO-QDs composites. The influence of varying HTO-QDs content on the microstructure and energy storage performance of the composites was systematically investigated using XRD, SEM, TEM, FTIR, and an electrochemical workstation. The results indicate that the uniformly dispersed HTO-QDs on the CNS surface significantly enhance the energy storage performance of the composite. Among them, CNS@HTO-QDs-25, with the highest HTO content, exhibits the maximum specific capacitance (485.3 F g^–1). Combined XPS analysis and first-principles calculations reveal that the HTO quantum dots not only contribute additional pseudocapacitance to enhance the electrochemical performance of the composite, but also provide strong interfacial interactions via the formation of M–O–C covalent bonds with the CNS matrix to improve the ion adsorption and transport capabilities of the composite material. Additionally, a symmetric supercapacitor (CNS@HTO-QDs-25||CNS@HTO-QDs-25) prepared in this study exhibits excellent specific capacitance, superior energy density, and good cycling stability, demonstrating an effective approach to the development of composites of transition metal oxides and carbon-based materials.

Sonodynamic therapy (SDT) offers deep-tissue cancer treatment potential but is limited by inefficient sonosensitizers like TiO₂ (due to wide bandgap and electron–hole recombination) and aggregation issues in doping various properties. To overcome this, we engineered polydopamine-dotted TiO₂ nanocomposites (PDA@TiO₂), utilizing the superior photothermal properties and anchoring ability of PDA to ensure TiO₂ dispersion and stability. The resulting PDA@TiO₂ demonstrated robust photothermal conversion and significantly enhanced sonodynamic ROS generation in vitro and in vivo; localized heat from photothermal therapy not only improved tumor penetration but also thermally augmented SDT efficacy by promoting electron–hole separation in TiO₂, creating a spatiotemporally synchronized synergistic effect. This dual-functional platform effectively eradicates tumors, overcoming limitations of individual therapies and doped TiO₂ dispersibility, demonstrating significant potential for treating deep-seated malignancies.