Nano Research最新文献

The electrocatalytic conversion of CO₂ to produce fuels and chemicals holds great promise, not only to provide an alternative to fossil feedstocks, but also to use renewable electricity to convert and recycle the greenhouse gas CO₂ to mitigate climate problems. However, the selectivity and reaction rates for the conversion of CO₂ into desirable carbon-based products, especially multicarbon products with high added value, are still insufficient for commercial applications, which is attributed to insufficiently favourable microenvironmental conditions in the vicinity of the catalyst. The construction of catalysts/electrodes with confined structures can effectively improve the reaction microenvironment in the vicinity of the electrodes and thus effectively direct the reaction towards the desired pathway. In this review, we firstly introduce the effects of the microenvironment at the electrode-electrolyte interface including local pH, local intermediate concentration, and local cation concentration on CO₂ reduction reaction (CO₂RR) as well as the mechanism of action, and then shed light on the microenvironmental modulation within the confined space, and finally and most importantly, introduce the design strategy of CO₂RR catalyst/electrode based on the confinement effect.

Droplet-based electricity generators (DEGs) leveraging triboelectric effects are simple and high-performance devices for harvesting energy from ubiquitous water droplets. Instantaneous power plays a vital role in wide applications of DEGs. However, the governing law of the maximum instantaneous power and matching resistance is lacking and their determination suffers from heavy repetitive experiments, hindering the development of DEGs. Herein, we propose a quick evaluation method for the internal droplet impedance, instantaneous peak power, maximum instantaneous power and matching resistance which exhibits broad universality and excellent accuracy. Moreover, effects of diverse factors pertaining to droplets and devices are fully investigated, highlighting that the maximum instantaneous power and matching resistance can be effectively regulated across multiple orders of magnitudes by controlling the salt concentration. Our findings shed insights into the understanding, evaluation, and regulation of instantaneous power for DEGs, and shall promote the renovation of the DEG technology.

Heterogeneous Fenton-like reaction shows great potential for eliminating organic substances (e.g. emerging organic contaminants (EOCs)) in water, which has been widely explored in recent decades. However, the catalytic mechanisms reported in current studies are extremely complicated because multiple mechanisms coexist and contribute to the removal efficiencies. Most importantly, heterogeneous systems show selective oxidation properties, which are crucial for improving the efficiencies in the catalytic elimination of organic substances. Thus, this critical review summarizes and compares the diverse existing mechanisms (non-radical and radical pathways) in heterogeneous catalytic processes based on recent studies. The typical oxidation mechanisms during selective advanced oxidation of EOCs were systematically discussed based on the following sections, including the selective adsorption and generation of reactive oxygen species (ROS) in photo/electron-Fenton and Fenton-like systems. Moreover, the non-radical pathways are discussed in depth by the singlet oxygen, high-valent metal-oxo, electron transfer process, etc. Moreover, the direct oxidative transfer process for the removal of EOCs was introduced in recent studies. Finally, the cost, feasibility as well as the sustainability of heterogeneous Fenton-like catalysts are summarized. This review offers useful guidance for developing suitable strategies to develop materials for decomposing the organic substrates.

Organic–inorganic hybrid perovskites are quite promising candidates in the field of electromagnetic wave (EMW) absorption due to their unique physicochemical properties. However, it is still a considerable challenge to satisfy the light weight, broad bandwidth, and strong absorption properties simultaneously. Herein, the solution of methylammonium lead iodide (MAPbI₃) perovskites was infiltrated into the pores of reduced graphene oxide (rGO) aerogels. After drying, a series of MAPbI₃/rGO composite aerogel (MGA) materials were synthesized by anchoring the MAPbI₃ perovskite nanoparticles to rGO sheets with the assistance of rGO templates. Through the adjustment of component ratios, excellent EMW absorption properties are obtained with the synergistic effects of polarization loss, conduction loss, and multiple reflection and scattering of MAPbI₃ and rGO. The porous structure of the aerogel and the suitable group distribution ratio allowed the MGA-4 samples to obtain excellent impedance matching and ultra-low density of ∼ 7.69 mg·cm⁻³. At a low filling ratio of 15 wt.%, the MGA-4 sample simultaneously achieves highly efficient and broadband EMW absorption performance at a thin thickness. The MGA-4 sample obtained a minimum reflection loss value of −64.35 dB and the effective absorption bandwidth (EAB) value of 5.4 GHz at a thickness of 2.08 mm and a maximum EAB (EAB_max) value of 6.2 GHz under 2.22 mm. The MGA-5 sample obtained a maximum EAB value of 6.4 GHz with the thinckness of 2.16 mm. Furthermore, the simulation results of the radar cross-section (RCS) verified the component-optimized composites are capable of achieving excellent EMW attenuation. This paper provides a new approach and valuable reference for the development of hybrid perovskite-based microwave absorption materials with lightweight, ultra-broadband, and strong absorption properties.

Sulfide-based solid-state electrolytes (SSEs) with high Li⁺ conductivity ((sigma_{text{Li}^{+}})) and trifling grain boundaries have great potential for all-solid-state lithium-metal batteries (ASSLMBs). Nonetheless, the in-situ development of mixed ionic-electronic conducting solid-electrolyte interphase (SEI) at sulfide electrolyte/Li-metal anode interface induces uneven Li electrodeposition, which causes Li-dendrites and void formation, significantly severely deteriorating ASSLMBs. Herein, we propose a dual anionic, e.g., F and N, doping strategy to Li₇P₃S₁₁, tuning its composition in conjunction with the chemistry of SEI. Therefore, novel Li_6.58P_2.76N_0.03S_10.12F_0.05 glass-ceramic electrolyte (Li₇P₃S₁₁-5LiF-3Li₃N-gce) achieved superior ionic (4.33 mS·cm⁻¹) and lowest electronic conductivity of 4.33 × 10⁻¹⁰ S·cm⁻¹ and thus, offered superior critical current density of 0.90 mA·cm⁻² (2.5 times > Li₇P₃S₁₁) at room temperature (RT). Notably, Li//Li cell with Li_6.58P_2.76N_0.03S_10.12F_0.05-gce cycled stably over 1000 and 600 h at 0.2 and 0.3 mA·cm⁻² credited to robust and highly conductive SEI (in-situ) enriched with LiF and Li₃N species. Li₃N’s wettability renders SEI to be highly Li⁺ conductive, ensures an intimate interfacial contact, blocks reductive reactions, prevents Li-dendrites and facilitates fast Li⁺ kinetics. Consequently, LiNi_0.8Co_0.15Al_0.05O₂ (NCA)/Li_6.58P_2.76N_0.03S_10.12F_0.05-gce/Li cell exhibited an outstanding first reversible capacity of 200.8/240.1 mAh·g⁻¹ with 83.67% Coulombic efficiency, retained 85.11% of its original reversible capacity at 0.3 mA·cm⁻² over 165 cycles at RT.

Intrinsic ferroelectric materials play a critical role in the development of high-density integrated device. Despite some two-dimensional (2D) ferroelectrics have been reported, the research on one-dimensional (1D) intrinsic ferroelectric materials remains relatively scare since 1D atomic structures limit their van der Waals (vdW) epitaxy growth. Here, we report the synthesis of 1D intrinsic vdW ferroelectric SbSI nanowires via a confined-space chemical vapor deposition. By precisely controlling the partial vapor pressure of I₂ and reaction temperature, we can effectively manipulate kinetics and thermodynamics processes, and thus obtain high quality of SbSI nanowires, which is determined by Raman spectroscopy and high-resolution scanning transmission electron microscopy characterizations. The ferroelectricity in SbSI is confirmed by piezo-response force microscopy measurements and the ferroelectric transition temperature of 300 K is demonstrated by second harmonic generation. Moreover, the in-plane polarization switching can be maintained in the thin SbSI nanowires with a thickness of 20 nm. Our prepared 1D vdW ferroelectric SbSI nanowires not only enrich the vdW ferroelectric systems, but also open a new possibility for high-power energy storage nanodevices.

Nanoscale materials often undergo structural, morphological, or chemical changes, especially in solution processes, where heterogeneity and defects may significantly impact the transformation pathways. Liquid phase transmission electron microscopy (TEM), allowing us to track dynamic transformations of individual nanoparticles, has become a powerful platform to reveal nanoscale materials transformation pathways and address challenging issues that are hard to approach by other methods. With the development of modern liquid cells, implementing advanced imaging and image analysis methods, and strategically exploring diverse systems, significant advances have been made in liquid phase TEM, including improved high-resolution imaging through liquids at the atomic level and remarkable capabilities in handling complex systems and reactions. In the past more than a decade, we spent much effort in developing and applying liquid phase TEM to elucidate how atomic level heterogeneity and defects impact various physicochemical processes in liquids, such as growth, self-assembly of nanoparticles, etching/corrosion, electrodeposition of alkali metals, catalyst restructuring during reactions, and so on. This article provides a brief review of the liquid phase TEM study of nanoscale materials transformations, focusing on the growth of nanomaterials with distinct shape/hierarchical structures, such as one-dimensional (1D) growth by nanoparticle attachment, two-dimensional (2D) growth with nanoparticles as intermediates, core-shell structure ripening, solid-liquid interfaces including those in batteries and electrocatalysis, highlighting the impacts of heterogeneity and defects on broad nanoscale transformation pathways.

Here, we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a metasurface. The geometrical dimensions of the proposed metasurface have been numerically optimized. The introduction of the metasurface allows exploitation of its robust resonance and superior impedance matching in low-frequency bands, thereby improving microwave absorption properties. The incorporation of the metasurface does not impact the wave transmission performance of the honeycomb core absorber at high-frequency band, thus preserving its high-frequency performance. This broadens the absorption range, leading to an expanded bandwidth. Simulation results reveal that the composite absorber (CA) exhibits strong absorption performance with an incident angle stability up to 45° for both transverse electric (TE) and transverse magnetic (TM) modes. The absorption mechanism of the CA has been investigated by using an equivalent circuit model and electromagnetic field analysis. A prototype was designed, fabricated, and tested to validate the proposed method. Both simulation and measurement results demonstrate that the prototype can achieve an average absorption rate exceeding 90% across a 1.0–18.0 GHz range. This study introduces an innovative technique for creating microwave absorbers for low-frequency wideband applications.

Nanozymes based on metal-organic frameworks (MOFs) have been concentrated on due to their naturally high-disperse metal active sites and the adjustable coordination chemistry. In this work, an N-rich melamine (Mel) was introduced into the Cu-MOF composed of copper(II) nitrate and 2-aminoterephthalic acid (Cu-NH₂-BDC-Mel) to mimic the laccase, which enzyme-like activities were assessed and applied in sensing analyses toward several phenols and amines. Compared to unmodified Cu-NH₂-BDC, the resulting Cu-NH₂-BDC-Mel exhibits enhanced laccase-like activity, superior stability and catalytic kinetics. It is demonstrated that melamine-doping has increased nitrogen content as well as the surface area, as a result, exhibits a lower Michaelis–Menten constant (K_m) (0.1877 mM) and higher maximum reaction rate (V_max) (1.7933 × 10⁻³ mM·min⁻¹) in comparison with that of natural laccase. Based on that, an efficient colorimetric sensing strategy for several phenols and amines was built up with excellent selectivity and anti-interference by using the laccase-like Cu-NH₂-BDC-Mel, the detection limits are 3.51 µM of adrenaline and 4.41 µM of dopamine. The work broadens the prospect development of bio-colorimetric sensing based on the ligand-modified Cu-MOFs nanozymes catalysis.

Although tumor cell membranes with broad-spectrum antigens have been explored for cancer vaccines for decades, their relatively poor capacity to stimulate immune responses, especially cellular immune responses, has limited their application. Here, we presented a novel bacterial and cancerous cell membrane fusogenic liposome for co-delivering cell membrane-derived antigens and adjuvants. Meanwhile, a programmed death-ligand 1 (PD-L1) inhibitor, JQ-1, was incorporated into the formulation to tackle the up-regulated PD-L1 expression of antigen-presenting cells (APCs) upon vaccination, thereby augmenting its antitumor efficacy. The fusogenic liposomes demonstrated significantly improved cellular uptake by APCs and effectively suppressed PD-L1 expression in bone marrow-derived dendritic cells (BMDCs) in vitro. Following subcutaneous vaccination, the nanovaccines efficiently drained to the tumor-draining lymph nodes (TDLNs), and significantly inhibited PD-L1 expression of both dendritic cells (DCs) and macrophages within the TDLNs and tumors. As a result, the liposomal vaccine induced robust innate and cellular immune responses and inhibited tumor growth in a colorectal carcinoma-burden mouse model. In summary, the fabricated cell membrane-based fusogenic liposomes offer a safe, effective, and easily applicable strategy for tumor immunotherapy and hold potential for personalized cancer immunotherapy.