Nanomaterials最新文献

As a renewable energy source, solar energy holds significant potential for addressing future energy and environmental challenges. Concurrently, hydrogen (H₂), as a clean and renewable energy carrier, has garnered substantial attention. Photoelectrocatalytic water splitting to produce H₂ represents an emerging green technology for converting solar energy into hydrogen energy, which has been highly valued by researchers. The key to advancing this technology lies in identifying photoelectrode materials with high catalytic activity and stability. In this study, dendritic α-Fe was synthesized via electrodeposition at the optimal potential of -1.4 V vs. Ag/AgCl for 300 s, and the photoelectrocatalytic performance of α-Fe₂O₃@Fe was enhanced through partial oxidation annealing at 300 °C for 6 h. This approach effectively addressed the issue of the short carrier transport distance in α-Fe₂O₃. The resulting partially oxidized α-Fe₂O₃@Fe(300 °C, 6 h) exhibited a photocurrent density of 281.1 μA/cm² at +0.55 V vs. Ag/AgCl, which was 2.23 times higher than that of the fully oxidized dendritic α-Fe₂O₃(500 °C, 2 h) (125.8 μA/cm²). The influence of deposition potential on photoelectrocatalytic performance was systematically explored, and the optimal deposition potential was identified. Additionally, surface modification with 0.15 wt% Pt (ultra-low loading) was employed to further improve the photocatalytic stability of α-Fe₂O₃(500 °C, 2 h). After continuous operation for 2 h, the photocurrent of the surface-modified sample decreased by only 6.5%, indicating a substantial enhancement in stability.

It is my pleasure as Guest Editor to introduce this Special Issue reprint, which brings together eleven high-quality contributions exploring both fundamental physics and practical applications in low-dimensional systems [...].

Thin liquid film flows of nanofluids over porous surfaces are central to applications ranging from microfluidic thermal management to precision coating technologies. This study investigates the hydrodynamic and thermal stability of a nanofluid flowing down a non-uniformly heated inclined porous plane subject to the Beavers-Joseph slip boundary condition. Using the long-wave approximation, a nonlinear evolution equation governing the film thickness is derived. The stability characteristics are systematically analyzed via linear stability theory, weakly nonlinear analysis, and fast Fourier transform (FFT) numerical simulations. Quantitative results indicate that the porous medium permeability, density difference, and Marangoni number act as destabilizing factors; specifically, increasing the porous parameter β (from 0 to 0.3), the density ratio ζ0 (from 0 to 5), and the Marangoni number Mn (from 0 to 0.3) significantly reduces the critical Reynolds number and accelerates the onset of interfacial instabilities. In contrast, increasing the nanoparticle volume fraction ϕ from 0 to 0.3 exerts a dominant stabilizing effect by elevating the critical Reynolds number and shrinking the unstable wavenumber domain. Furthermore, nonlinear simulations confirm that higher nanoparticle concentrations effectively suppress the saturation amplitude of disturbances, promoting the eventual stabilization of the liquid film.

Poly(ethylene oxide) (PEO)-based solid electrolytes are promising candidates for solid-state lithium metal batteries because of their flexibility and ease of processing. However, their practical application is limited by insufficient mechanical strength and poor interfacial stability. Conventional single-filler strategies typically improve either ionic conductivity or mechanical robustness, making it challenging to simultaneously optimize both properties. In this work, a dual-ceramic strategy is proposed that integrates inert and active ceramic fillers with complementary roles to construct a polymer electrolyte that is both mechanically robust and ionically conductive. The inert ceramic filler promotes lithium-salt dissociation and Li⁺ transport, whereas the active ceramic filler enhances structural integrity and suppresses lithium dendrite growth, enabling a synergistic balance between ionic transport and cycling stability. As a representative implementation, paraelectric SrTiO₃ and Li⁺-conducting Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) are incorporated into the PEO/LiTFSI matrix to construct a composite solid electrolyte (PLLS). The optimized PLLS electrolyte, containing 8 wt% STO and 5 wt% LLZTO, exhibits a high ionic conductivity of 4.48×10-4Scm-1, an increased Li⁺ transference number of 0.20, and a wide electrochemical stability window of 5.165 V versus Li/Li⁺ at 60 °C. Li/Li symmetric cells demonstrate stable lithium plating/stripping for nearly 2000 h at a current density of0.2mAcm-2. Furthermore, LiFePO₄/Li full cells retain 92.1% of their initial capacity after 500 cycles at 1 C, and stable cycling performance is also achieved with high-voltage LiCoO₂ cathodes. These results demonstrate that the proposed dual-ceramic synergistic strategy offers an effective and potentially generalizable approach to enhancing the durability of PEO-based solid electrolytes for long-life solid-state lithium metal batteries.

The pursuit of energy-efficient technologies is crucial for achieving sustainability amid rising global energy demands and climate concerns. MXenes-a class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides-have recently attracted significant attention in thermoelectric (TE) research due to their outstanding electrical conductivity, tunable surface chemistry, and unique layered structures. This review uniquely focuses on the integration of MXenes into flexible and wearable platforms, offering a systematic analysis of material innovations specifically tailored to mechanical compliance. Beyond material-level transport properties, we critically evaluate actual device-level demonstrations, including fabrication strategies for flexible TE generators (f-TEGs), that achieve impressive outputs, such as Seebeck voltages of up to 399.9 mV for 200 p-n modules. To assist readers in gauging progress, we provide a comprehensive comparative analysis of diverse MXene architectures, summarized in a quantitative benchmark table covering Seebeck coefficients (S), electrical conductivity (σ), power factor (PF), and ZT values. Notably, experimental optimization has led to performance breakthroughs, with MXene-based flexible films exhibiting power factors exceeding 2100 µW m^-1 K^-2 and ZT values as high as 1.33 at room temperature. Finally, critical challenges, including environmental stability and large-scale manufacturing, are discussed alongside future perspectives on multifunctional MXene systems.

The escalation of thermal runaway in lithium-ion batteries presents severe safety hazards that necessitate advanced monitoring protocols to ensure early warning of potential failures. Carbon dioxide (CO₂) is released during preliminary decomposition well before catastrophic failure occurs, thereby providing a strategic advantage for early-stage warning. Consequently, identifying materials with high-selective CO₂ recognition is an essential prerequisite for developing reliable sensing platforms. This study integrates Grand Canonical Monte Carlo simulations with Random Forest (RF) models to systematically screen 1470 MOFs from the CoRE-MOF 2019 database. The screening process evaluates selective CO₂ recognition under multicomponent competitive adsorption conditions involving CO₂, C₂H₄, and O₂. The performance evaluation is based on working capacity, selectivity, and the trade-off between working capacity and selectivity (TSN). The RF model achieves high predictive accuracy, with tested R² exceeding 0.92 on the test samples. Shapley Additive Explanations (SHAP) interpretability analysis identifies Q⁰_st(CO₂), Q⁰_st(C₂H₄), WEPA, K_H(C₂H₄), and ETR as key performance drivers. The results indicate that CO₂ selectivity is constrained by the binding strength of competing C₂H₄. Optimal materials tend to have hard Lewis acid centers and polar inorganic clusters to minimize non-specific π-interactions with interfering species. Top-performing MOFs require balanced structural features, concentrating in moderate surface areas (965-1975 m²/g), narrow pore windows (PLD ≈ 4-7 Å, LCD ≈ 5.5-9.6 Å), high void fractions above 0.6, and low densities below 1.3 g/cm³. AJOTEY emerges as the optimal candidate with a TSN of 6.43 mol/kg, combining substantial working capacity (4.57 mol/kg) with strong selectivity (25.52). These results will accelerate the discovery of sensing materials and provide a practical pathway for MOF-based CO₂ sensor development to enhance lithium-ion battery safety.

This study analyzed the low-frequency noise characteristics of nanosheet field-effect transistors (NSFETs) using technology computer-aided design (TCAD) simulations. In particular, the effects of shallow trench isolation (STI) depth and gate-insulator interface trap density on the device's flicker noise power spectral density (PSD) were systematically evaluated. The simulation results show that as STI depth increases, excessive trap charges formed in the STI oxide can deplete or invert the substrate beneath the STI layer, reducing the threshold voltage of parasitic transistors and thereby increasing flicker noise. In contrast, the shallow STI structure's trapped charge density was found to be lower than in thicker structures. Additionally, when an HfO₂-ZrO₂ (HZO)-based ferroelectric insulator is applied, improved gate-field control and reduced trap-induced noise are observed compared to HfO₂. Optimization results indicate that the optimal noise performance is achieved with an STI depth of 3 nm and a SiO₂/silicon interface trap density of 1 × 10¹⁰ eV^-1cm^-2. This study provides a design direction for low-noise NSFETs through structural (STI) and material (interface traps and HZO) optimization and is expected to contribute to the development of next-generation low-power, high-reliability logic devices.

Spin-orbit torque (SOT)-based spintronic devices have emerged as a preferred candidate for next-generation artificial synaptic devices due to their advantages of non-volatility, high speed, and low power consumption. The development of high-performance SOT-based artificial synaptic devices relies on the breakthrough in SOT-driven magnetization switching, wherein the performance regulation and structural design of the magnetic layer are the core critical factors. In this work, the Co/Ho multilayer system is employed as the magnetic layer to investigate its SOT-driven magnetization switching characteristics and application potential in artificial synapses. By regulating the periodic parameters of the Co/Ho multilayer structure, high perpendicular magnetic anisotropy (PMA) can be stably maintained in devices with relatively thick ferrimagnetic layers. Moreover, we elucidate the role of the antiferromagnetic coupling interface between Co and Ho in the multilayer structure in enhancing SOT efficiency and demonstrate the achievement of a high spin Hall angle of up to 0.22. The high SOT efficiency of the system enables it to drive the 8.4 nm-thick magnetic layer to achieve highly stable magnetization switching. Multistate magnetization switching behavior is observed, which can be used to simulate synaptic weight updates in neuromorphic networks, demonstrating the broad application prospects of this system in the field of artificial neural networks.

Efficient ozone synthesis has always been the pursuit of ozone workers and the foundation for the industrial application of ozone reactors. Recently, with continuous breakthroughs in materials and catalyst research, as well as the rapid development of advanced characterization technologies, introducing catalysts into dielectric barrier discharge (DBD) to build a DBD-catalyst coupled system has developed into an advanced means of improving ozone synthesis and attracted widespread attention. This review aims to provide a systematic summary for the research status of the DBD-catalyst coupled system in the field of ozone synthesis. Firstly, the structure of DBD reactors (type and shape of the electrode, etc.), catalyst types and the coupling method of DBD and catalysts (such as catalyst packing, catalyst coating/film) for the DBD-catalyst coupled system are discussed. Subsequently, the relevant mechanisms involving plasma gas-phase reactions and gas-solid interface reactions for elevating discharge ozone synthesis through coupling catalysts with DBD are summarized and analyzed. Afterwards, the research status of the DBD-catalyst coupled system in the field of ozone synthesis is surveyed. At present, the optimal ozone synthesis performance of the reactor with packed catalyst in air plasma (γ-Al₂O₃ sphere) is 0.96 g/Nm³ and 103 g/kWh, and in oxygen plasma (SiO₂ particle) is 130 g/Nm³ and 91 g/kWh, respectively. For the reactor coupled with a catalyst coating, the performance reaches 19.3 g/Nm³ and 320 g/kWh in oxygen plasma (TiO₂). Then, advanced plasma parameter detection techniques (i.e., optical emission spectroscopy and two-photon absorption laser-induced fluorescence) are expatiated to observe the changes in plasma parameters within the discharge system and then provide strong support for further in-depth research and analysis of the enhancement mechanism of coupling catalysts on ozone synthesis. Finally, a short conclusion, together with the current challenges and future opportunities of the DBD-catalyst coupled system in improving ozone synthesis, are proposed.

Integrating diamond with GaN provides an effective pathway to mitigate self-heating. However, the thermal boundary resistance (TBR) remains a persistent bottleneck for further heat dissipation. While carbon (C) diffusion into the SiNx interlayer is known to reduce TBR, the associated stress evolution and its impact on device performance remain underexplored. In this work, the synergistic regulation of heat transport and electrical performance induced by C diffusion was systematically investigated. Transmission electron microscopy (TEM) was employed to characterize the interfacial microstructure and the influence of C diffusion on the interface. To further assess the resulting impact on heat dissipation, transient thermoreflectance was utilized to precisely quantify the thermal transport within the heterostructures. Classical molecular dynamics (MD) simulations were then performed to analyze the underlying physical mechanisms, revealing that intensifying C diffusion increases the phonon density of states overlap and effectively reduces the TBR. Furthermore, the intrinsic stress was quantified through geometric phase analysis (GPA) based on TEM images, demonstrating that the stress induced during the diffusion process propagates to the AlGaN/GaN heterostructure. Crucially, this stress modulation enhances the piezoelectric polarization by approximately 32%, resulting in a 5% increase in the two-dimensional electron gas (2DEG) sheet density. These findings provide a comprehensive strategy for optimizing the thermal management and mechanical reliability of high-power GaN devices.