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.

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.

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.

Ammonia plays a vital role in present agriculture and industry, and is also regarded as a next-generation clean energy carrier. The development of electrocatalysis raises an opportunity to make ammonia synthesis compatible with intermittent and variable renewable energy sources such as solar and wind energy. However, the direct ammonia electrosynthesis from N₂ reduction is still challenging due to the much easier hydrogen evolution competition reaction. In this perspective, we propose a novel strategy for ammonia electrosynthesis from air and water based on the coupling of anodic nitrogen oxidation and cathodic nitrate reduction. Possible methods for breaking the bottlenecks of anodic nitrogen oxidation and cathodic nitrate reduction are discussed separately. After that, key issues that need to be considered in the coupled system are proposed for the application of this strategy.

Lipid nanoparticles (LNPs) have delivered RNA to hepatocytes in patients after intravenous administration. These clinical data support efforts to design LNPs that transfect cells in the central nervous system (CNS). However, delivery to the CNS has been difficult, in large part because quantifying on-target delivery alongside common off-target cell types in adult mice remains challenging. Here we report methods to isolate different cell types from the CNS, and subsequently present mRNA delivery readouts using a liver-detargeted LNP. These data suggest that LNPs without targeting ligands can transfect cerebral endothelial cells in mice after intravenous administration. Given the difficulty of crossing the blood–brain barrier, they also underscore the value of quantifying delivery in the CNS with cell-type resolution instead of whole-tissue resolution.

Dimensional regulation in polyoxometalates is an effective strategy during the design and synthesis of polyoxometalates-based high proton conductors, but it is not available to date. Herein, the precise regulation of dimensionality has been realized in an unprecedented gigantic molybdenum blue wheel family featuring pentagonal {(W)Mo₅} motifs through optimizing the molar ratio of Mo/W, including [Gd₂Mo₁₂₄W₁₄O₄₂₂(H₂O)₆₂]³⁸⁻ (0D-{Mo₁₂₄W₁₄}, 1), [Mo₁₂₆W₁₄O₄₄₁(H₂O)₅₁]⁷⁰⁻ (1D-{Mo₁₂₆W₁₄}_n, 2), and [Mo₁₂₄W₁₄O₄₃₀(H₂O)₅₀]⁶⁰⁻ (2D-{Mo₁₂₄W₁₄}_n, 3). Such important {(W)Mo₅} structural motif brings new reactivity into gigantic Mo blue wheels. There are different numbers and sites of {Mo₂} defects in each wheel-shaped monomer in 1–3, which leads to the monomers of 2 and 3 to form 1D and 2D architectures via Mo–O–Mo covalent bonds driven by {Mo₂}-mediated H₂O ligands substitution process, respectively, thus achieving the controllable dimensional regulation. As expected, the proton conductivity of 3 is 10 times higher than that of 1 and 1.7 times higher than that of 2. The continuous proton hopping sites in 2D network are responsible for the enhanced proton conductivity with lower activation energy. This study highlights that this dimensional regulation approach remains great potential in preparing polyoxometalates-based high proton conductive materials.

Crystallinity and crystal structure greatly influence the photocatalytic behavior of photocatalysts. Pristine g-C₃N₄ produced by traditional thermal-induced polycondensation reaction bears low crystallinity and thus poor photoactivity, which originates from the incomplete polymerization of the precursor containing amine groups, abundant hydrogen bonds, and unreacted amino, as well as cyanide functional groups in the skeleton. During photocatalytic process, these residual functional groups often work as electron trap sites, which may hinder the transfer of electrons on the plane, resulting in low photoactivity. Fortunately, crystalline carbon nitride (CCN) was reported as a promising photocatalyst because its increased crystallinity not only reduces the number of carriers recombination centers, but also increases charge conductivity and improves light utilization due to extended π-conjugated systems and delocalized π-electrons. As such, we summarize the recent studies on CCN-based photocatalysts for the photoactivity enhancement. Firstly, the unique structure and properties of CCN materials are presented. Next, the preparation methods and modification strategies are well outlined. We also sum up the applications of CCN-based materials in the environmental purification and energy fields. Finally, this review concerning CNN materials ends with prospects and challenges in the obtainment of high crystallinity by effective techniques, and the deep understanding of photocatalytic mechanism.

Powered by clean energy, the hydrogen fuel production from seawater electrolysis is a sustainable green hydrogen technology, however, chlorine corrosion and correlative oxidation reactions severely erode the catalysts. Our previous work demonstrates that direct seawater electrolysis without a desalination process and strong alkali addition can be realized by introducing a hard Lewis acid oxide on the catalyst surface to capture OH⁻. However, the criteria for selecting Lewis acid oxides and the origin of OH⁻ enrichment in chlorine chemistry inhibition on the catalyst surface remain unexplored. Here, we compare the ability of a series of Lewis acid oxides with different acidity constants (pKa), including MnO₂, Fe₂O₃, and Cr₂O₃, to enrich OH⁻ on the Co₃O₄ anode catalyst surface. Comprehensive analyses suggest that the lower pKa value of the Lewis acid oxide, the higher concentration of OH⁻ enriched on Co₃O₄ surface, and the lower Cl⁻ concentration. As established correlation among pKa of Lewis acid oxide, OH⁻ enrichment and Cl⁻ repulsion provide direct guidance for future design of highly active, selective and durable catalysts for natural seawater electrolysis.