Well-defined Nanostructures Research Articles

Reaction Pathway Regulation for Gaseous and Liquid Products of Electrocatalytic CO2 Reduction under Adsorbate Interactions.

Halide anion adsorption on transition metals can improve the performance of electrochemical CO2 reduction reaction (CO2RR), while the specific reaction mechanisms governing selective CO2RR pathways remain unclear. In this study, we demonstrate for the first time the distinct pathways for gaseous (CO) and liquid products (formate and ethanol) on the well-defined Ag-Cu nanostructures with controlled chlorination, respectively. We show that CO2 conversion to CO on Ag/AgCl can be tuned by adjusting the thickness of AgCl layer, achieving a Faradaic efficiency (FE) near 100% over a broad potential range in a 0.5 M KHCO3 using flow cell. In contrast, the optimized Cl-Ag/Cu system enables the conversion of CO2 into liquid products including formate and ethanol with a total FE nearing 100%, delivering high current density under similar conditions. In situ infrared experiments and theoretical calculations reveal that the lateral adsorbate of *OCHO intermediate facilitates the thermodynamics of both the CO pathway on Cl-Ag(111) and the formate pathway on Cl-Ag/Cu(111) by reducing Gibbs free energy barriers of each potential-limit step. This work uncovers the role of chlorination in the tuning of C-bound or O-bound intermediates during CO2RR on Ag-Cu catalysts, determining the reaction pathway under lateral adsorbate effects.

Visualizing supramolecular assembly behavior, stimulus response, and solid state emission of higher-order Pt2+ aggregates.

Here, we present the first instance of a highly efficient red tetramer aggregate with tunable emission based on a cationic platinum(II) complex in conjunction with a silver cluster anion counterpart. This system exhibits multicolor emission response behaviors, which can be conveniently and directly detected through spectroscopic analysis, showcasing intriguing luminescence changes. The self-assembly of Pt⋯, π-π, and hydrogen bonding interactions not only enables an intriguing color adjustment from green to yellow emission, and eventually to red emission, but also demonstrates the co-existence of the monomer, excimer, and aggregation. These phenomena are further accompanied by well-defined nanostructures. The self-assembly process of these structures exhibits an isodesmic growth mechanism, which is dependent on temperature. In this regard, it exhibits potential applicability in multi-mode logic gates that rely on external stimuli such as concentration, solvent, and temperature. The sensitivity of the aggregates towards chemical stimuli combined with their exceptionally bright emission characteristics renders them suitable for diverse applications including solid-state lighting sensing mechanisms and anticounterfeiting measures. The multi-stimuli responsive phosphorescence and self-assembly behaviors of the cationic platinum(II) complex were substantiated by X-ray crystal structure determination, 1H NMR analysis spectroscopic investigations, computational calculations and scanning electron microscopy (SEM) studies.

Computational supported experimental insights in adsorption of Congo Red using ZnO/doped ZnO in aqueous solution

The rapid growth of industrialisation has led to the discharge of harmful effluents into water bodies, severely disrupting the balance of ecosystems. The detection and removal of dyes from wastewater remains a significant challenge. In this study, we report the synthesis of zinc oxide (ZnO) and its doped derivatives through a facile chemical method, followed by comprehensive characterisation and analysis to assess their potential in various applications. The structural properties of the synthesised materials were confirmed by X-ray diffraction (XRD), which verified their crystalline nature and phase purity. Morphological analysis using field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray analysis (EDAX) revealed well-defined nanostructures and uniform elemental distribution. The adsorption ability of the synthesized adsorbents was investigated through electrochemical methods, cyclic voltammetry and Tafel plots, which demonstrated enhanced conductivity and charge transfer characteristics. Additionally, theoretical studies through molecular modelling and molecular dynamic simulations were employed to elucidate the interactions between Congo red molecules and the surface of the synthesized compounds. Adsorption experiments were conducted to evaluate the efficacy of ZnO and its doped variants as adsorbents. To investigate any structural or functional changes after dye adsorption FTIR and XRD were compared, provided a deeper insight into the adsorption mechanism. This multi-faceted approach highlights the potential of ZnO-based materials for effective wastewater treatment and other environmental applications.

Liquid Crystal Promoted Self-Assembly of Statistical Copolymers into Diverse Nanostructures with Precise Dimensions.

In both natural and synthetic systems, the segregation of multicomponent entities is vital for regulating functions and the ultimate usage of materials. To accomplish the desired properties via nanosegregation or microphase separation, great effort is usually demanded in the synthesis. For example, microphase-separated block copolymers rely on the delicate controlled/living polymerization of different monomers in sequence. Here, we demonstrate that a facile one-pot copolymerization can generate statistical side-chain copolymers exhibiting well-defined and diverse nanostructures. Two hemiphasmidic (or wedge-shaped) cyclooctene monomers were designed, differing in the peripheral tails of the wedges (dodecyl vs. tetraethylene glycol), with lengths of ca. 1 nm. When combining the two monomers together, the statistical copolymers can show columnar liquid crystal (LC) phase and microphase-separated structures of the two monomers, including sphere, cylinder, double gyroid, and lamella. To the best of our knowledge, this is the first time the gyroid phase has been achieved in statistical copolymers. We further demonstrate that changing the side chains to calamitic (or rod-like) mesogens or the backbone to less flexible polynorbornene, the statistical copolymers can also undergo microphase separation of the side chains. The intrinsic self-assembly scheme of statistical copolymers with mesogenic side chains, which are chemically accurate, affords the resultant nanostructures with precise periodicities at the 10- or sub-10-nm scale. Given the small chemical difference between the side-chain tails, microphase separation is promoted by the anisotropic packing of mesogens. It is validated that the statistical side-chain LC copolymers can be a versatile platform for creating nanostructured materials with tailored functionalities.

Fabrication of patterned TiO2 nanotube layers utilizing a 3D printer platform and their electrochromic properties

Anodization enables nano-structure fabrication through electrochemical parameter control. While various approaches exist for creating localized or patterned oxide layers, many are complex and time-consuming. This study adopted a commercial 3D printer for high-speed (1 mm/s) anodization, forming TiO2 nanotube layers on Ti substrates in G-code-designed patterns. Comprehensive characterization using XRD, SEM, XPS, and simulated electric field distribution analysis revealed well-defined nanostructures and provided insights into the formation mechanism. Furthermore, viologen-anchored TiO2 showed significantly improved electrochromic performance compared to pristine TiO2, with a higher reflectance difference (46.2% vs. 6.85%). This 3D printing-anodization hybrid method offers a rapid approach to fabricating patterned TiO2 nanostructures, showing promise for electrochromic devices with enhanced optical modulation capabilities.

Design rules for catalysis in single-particle plasmonic nanogap reactors with precisely aligned molecular monolayers

Plasmonic nanostructures can both drive and interrogate light-driven catalytic reactions. Sensitive detection of reaction pathways is achieved by confining optical fields near the active surface. However, effective control of the reaction kinetics remains a challenge to utilize nanostructure constructs as efficient chemical reactors. Here we present a nanoreactor construct exhibiting high catalytic and optical efficiencies, based on a nanoparticle-on-mirror (NPoM) platform. We observe and track pathways of the Pd-catalysed C-C coupling reaction of molecules within a set of nanogaps presenting different chemical surfaces. Atomic monolayer coatings of Pd on the different Au facets enable tuning of the reaction kinetics of surface-bound molecules. Systematic analysis shows the catalytic efficiency of NPoM-based nanoreactors greatly improves on platforms based on aggregated nanoparticles. More importantly, we show Pd monolayers on the nanoparticle or on the mirror play significantly different roles in the surface reaction kinetics. Our data provides clear evidence for catalytic dependencies on molecular configuration in well-defined nanostructures. Such nanoreactor constructs therefore yield clearer design rules for plasmonic catalysis.

Role of Morphology on Zinc Oxide Nanostructures for Efficient Photoelectrochemical Activity and Hydrogen Production.

Energy generation today heavily relies on the field of photocatalysis, with many conventional energy generation strategies now superseded by the conversion of solar energy into chemical or thermal energy for a variety of energy-related applications. Global warming has pointed to the urgent necessity of moving away from non-renewable energy sources, with a resulting emphasis on creating the best photocatalysts for effective solar conversion by investigating a variety of material systems and material combinations. The present study explores the influence of morphological changes on the photoelectrochemical activity of zinc oxide nanostructures by exploiting electrodeposition and capping agents to control the growth rates of different ZnO facets and obtain well-defined nanostructures and orientations. A zinc nitrate (Zn (NO3)2) bath was used to electrodeposit ZnO nanostructures on an indium tin oxide glass (ITO) substrate at 70 °C with an applied potential of -1.0 V. Ethylenediamine (EDA) or ammonium fluoride (NH4F) were added as capping agents to the zinc nitrate bath. Extensive evaluation and characterization of the photoelectrochemical (PEC) capabilities of the resulting morphology-controlled zinc oxide nanostructures confirmed that altering the ZnO morphology can have positive impacts on PEC properties.

Multi-synergy enabling Ni-doped MoS2@N-doped carbon composite as versatile catalysts toward hydrogen production and photovoltaics

Construction of efficient non-precious catalyst with desired chemical composition and well-defined nanostructure is of great essential to enhance the kinetics of hydrogen evolution reaction (HER) and triiodide (I3−) reduction reaction (IRR), which is conducive to promote the development of green hydrogen production and obtain impressive photovoltaic performance of dye-sensitized solar cells (DSSCs). Herein, ZIF-8 derived N-doped carbon (NC) wrapped with two-dimensional Ni-doped MoS2 nanosheets (Ni–MoS2@NC) are elaborately designed. The catalytic activity of Ni–MoS2@NC for HER and IRR are significantly improved by modifying electronic structure through heteroatom doping. The optimized Ni–MoS2@NC has lower overpotential of 122 mV at 10 mA cm−2 in comparison with counterpart. Meanwhile, the power conversion efficiency (PCE) of DSSCs based on Ni–MoS2@NC CE catalyst is comparable to that of Pt. Density functional theory (DFT) calculation is used to unveil the mechanism of Ni–MoS2@NC for alkaline HER and IRR, namely, the multi-synergy of various sites endows Ni–MoS2@NC with appropriate Gibbs free energy for H∗ adsorption and water dissociation energy, while the top and interfacial S sites of Ni–MoS2@NC are responsible for the adsorption and activation of I3−. Our work provides a feasible route to design efficient catalysts in the field of energy conversion and understand mechanism.

A Family of Twisted Chiral Engineered Inorganic Nanoarchitectures.

Chiral inorganic materials possess unique asymmetric properties that could significantly impact various fields. However, their practical application has been hindered by challenges in creating structurally robust chiral materials. We report the synthesis of well-defined chiral-shaped hollow cobalt oxide nanostructures, extendable to a family of chalcogenides including sulfide, selenide, and telluride through topological transformations. Taking chiral cobalt oxide nanostructures as a representative material, we demonstrate precise control over their chiral architectures, enabling fine-tuning of parameters, such as twist degrees, handedness, and compositions. These chiral nanostructures exhibit high spin selectivity effects that influence the electron transfer processes in catalytic reactions. Leveraging this spin-selective behavior, the chiral cobalt oxide nanoarchitectures demonstrate enhanced electrocatalytic performance in the oxygen evolution reaction compared to their achiral counterparts. Our findings not only expand the library of chiral inorganic materials but also advance the application of chiral effects in fields such as catalysis, spintronics, and beyond.

A disposable fiber-optic plasmonic sensor for chemical sensing

The integration of fiber optics and plasmonic sensors is promising to improve the practical usability over conventional bulky sensors and systems. To achieve high sensitivity, it typically requires fabrication of well-defined plasmonic nanostructures on optical fibers, which greatly increases the cost and complexity of the sensors. Here, we present a fiber-optic sensor system by using chemical absorption of gold nanoparticles and a replaceable configuration. By functioning gold nanoparticles with aptamers or antibodies, we demonstrate the applications in chemical sensing using two different modes. Measuring shift in resonance wavelength enables the Pb2+ detection with a high linearity and a limit of detection of 0.097 nM, and measuring absorption peak amplitude enables the detection of E. coli in urinary tract infection with a dynamic range between 103 to 108 CFU/mL. The high sensitivity, simple fabrication and disposability of this sensing approach could pave the way for point-of-care testing with fiber-optic plasmonic sensors.

Well-Dispersed Manganese-Oxo Clusters as Anode Materials for High-Performance Lithium Ion Batteries.

Metal-oxo clusters show great promise in lithium ion battery applications as anode materials by virtue of their native nature of well-defined nanostructures and multielectron redox activities. However, their intrinsic unsatisfactory electrical conductivity and tendency to aggregation make them difficult to fully utilize. Herein, a well-dispersed Mn12O12(CH3COO)16(H2O)4 (denoted as Mn12) cluster is constructed by rationally adopting carbon dots (CDs) with nanosize and high conductivity as stabilizers. Thanks to the fully exposed redox sites of Mn12 clusters and additional interfacial energy storage mechanism, the optimized Mn12/CDs-1:20 anode delivers a high specific capacity of 1643 mAh g-1 at 0.2 A g-1 (0.25 C) and exhibits outstanding rate and cycling capabilities. This paper provides a green and efficient paradigm to synthesize well-dispersed manganese-oxo clusters for the first time and builds a new platform for cluster-based energy storage.

Self-Assembly in Living Cells: Bottom-Up Syntheses in Natural Factory.

In situ self-assembly in living systems is referred to as the processes that regulate assembly by stimuli-responsive reactions at target sites under physiological conditions. Due to the advantages of precisely forming well-defined nanostructures at pathological lesions, in situ-formed assemblies with tailored bioactivity are promising for the development of next-generation biomedical agents. In this Perspective, we summarize the progress of in situ self-assembly of peptides in living cells with an emphasis on the state-of-the-art strategies regulating assembly processes, establishing complexity within assembly systems, and exploiting their applications in biomedicines. We also provide our forward conceiving perspectives on the challenges in the development of in situ assembly in living cells to demonstrate its great potential in creating biomaterials for healthcare in the future.

Bonding-Directed Crystallization of Ultra-Long One-Dimensional NbS3 van der Waals Nanowires.

The rediscovery of one-dimensional (1D) and quasi-1D (q-1D) van der Waals (vdW) crystals ushered the realization of nascent physical properties in 1D that are suitable for applications in photonics, electronics, and sensing. However, despite renewed interest in the creation and understanding of the physical properties of 1D and q-1D vdW crystals, the lack of accessible synthetic pathways for growing well-defined nanostructures that extend across several length scales remains. Using the highly anisotropic 1D vdW NbS3-I crystal as a model phase, we present a catalyst-free and bottom-up synthetic approach to access ultralong nanowires, with lengths reaching up to 7.9 mm and with uniform thicknesses ranging from 13 to 160 nm between individual nanowires. Control over the synthetic parameters enabled the modulation of intra- and interchain growth modalities to selectively yield only 1D nanowires or quasi-2D nanoribbons. Comparative synthetic and density functional theory (DFT) studies with a closely related nondimerized phase, ZrS3, show that the unusual preferential growth along 1D can be correlated to the strongly anisotropic bonding and dimeric nature of NbS3-I.

Investigating the hybrid potential of PVA-chitosan-loaded TiO2@NiO films for advanced conductivity and dielectric performance

The synthesis and characterization of PVA-chitosan-NiO, PVA-chitosan-TiO2, and PVA-chitosan-TiO2@NiO films have opened avenues for tailoring materials with specific electrical, dielectric, and optical properties. The synergistic effects arising from the combination of polymers and metal oxides offer a platform for further optimization and application-specific tuning. The synthesis process successfully incorporated NiO and TiO2 nanoparticles into the PVA-chitosan matrix, creating three distinct films: PVA-chitosan-NiO, PVA-chitosan-TiO2, and PVA-chitosan-TiO2@NiO. Structural analyses, including X-ray diffraction (XRD) and scanning electron microscopy (SEM), revealed well-defined nanostructures with crystalline metal oxide dispersions. Dielectric characterization demonstrated frequency-dependent behavior, elucidating the influence of metal oxides on dielectric constants and loss tangents. Cole–Cole plots provide insights into relaxation processes and can guide applications in capacitors and energy storage devices. Conductivity measurements highlight the enhanced electrical performance of NiO and TiO2. This study provides a foundation for future research on the development of advanced functional materials for a wide range of technological applications. The insights gained from this work contribute to the growing body of knowledge on polymer-metal oxide composites and pave the way for innovations in electronic, optoelectronic, and energy-related technologies.

Synthesis of Highly Oriented Nanocrystal Thin-Films and Their Applications to Electrochemical Devices

The precisely defined particle assembly at the nanoscale with simultaneously scalable patterning at the microscale is indispensable for enabling functionality and improving the performance of devices. While synthetic advances in the past decades now allow precise control of their size, shape, and composition, they must be processed from dispersion into functional films for many applications, which presents additional challenges. In this work, we introduce the self-assembly of inorganic nanoubes (Co3O4 NCs) and we also describe the fabrication of centimeter-scale NC superlattice thin-films on silicone substrate with anisotropic NC building blocks, thin-film patterning, and the supercrystal formation of superlattice structures. As a result, the Raman spectra of Co3O4 NC thin-films clearly exhibits the distinct feature of vibration modes of Co3O4 and synchrotron-based X-ray diffraction techniques showed the Co3O4 NCs order into [100] aligned arrays. Also, the uniformly prepared Co3O4 NC building blocks and thin-films were examined by field-emission scanning electron microscopy analysis and it shows well-defined nanostructures with ~13nm-side of NCs and ~3nm space between self-assembled NCs. To investigate the distinct feature of functional films, we prepared various type of device structures (memory, electrode, gas sensor) and examined the performances. In case of memristor, the device exhibits excellent bipolar resistance switching characteristics with better reliability and stability over various polycrystalline metal oxide nanostructures. Utilizing our approach enables the creation of miniaturized devices, followed by the transfer of NC thin-films onto TEM grids. Subsequent in-situ TEM analysis offers the potential to observe unique phenomena at the nano-scale, unveiling phase transitions in nanocrystalline materials or electrochemical reaction mechanisms previously unexplored by researchers.

Development and Evaluation of Docetaxel-Loaded Nanostructured Lipid Carriers for Skin Cancer Therapy.

This study focuses on the design, characterization, and optimization of nanostructured lipid carriers (NLCs) loaded with docetaxel for the treatment of skin cancer. Employing a systematic formulation development process guided by Design of Experiments (DoE) principles, key parameters such as particle size, polydispersity index (PDI), zeta potential, and entrapment efficiency were optimized to ensure the stability and drug-loading efficacy of the NLCs. Combined XRD and cryo-TEM analysis were employed for NLC nanostructure evaluation, confirming the formation of well-defined nanostructures. In vitro kinetics studies demonstrated controlled and sustained docetaxel release over 48 h, emphasizing the potential for prolonged therapeutic effects. Cytotoxicity assays on human umbilical vein endothelial cells (HUVEC) and SK-MEL-24 melanoma cell line revealed enhanced efficacy against cancer cells, with significant selective cytotoxicity and minimal impact on normal cells. This multidimensional approach, encompassing formulation optimization and comprehensive characterization, positions the docetaxel-loaded NLCs as promising candidates for advanced skin cancer therapy. The findings underscore the potential translational impact of these nanocarriers, paving the way for future preclinical investigations and clinical applications in skin cancer treatment.

Nanostructured transition metal dichalcogenides-based colorimetric sensors: Synthesis, characterization, and emerging applications.

Nanostructured transition metal dichalcogenides (TMDCs) have garnered significant attention as prospective materials for the development of highly sensitive and versatile colorimetric sensors. This work explores the synthesis, characterization, and emerging applications of TMDC-based sensors, focusing on their unique structural aspects and inherent properties. The synthesis methods involve tailored fabrication techniques, such as chemical vapor deposition and hydrothermal processes, aimed at producing well-defined nanostructures that enhance sensor performance. Characterization techniques, including microscopy, spectroscopy, and surface analysis, are employed to elucidate the structural and chemical features of the nanostructured TMDCs. These analyses provide insights into the correlation between the material's morphology and its sensing capabilities. The colorimetric sensing mechanism relies on the modulation of optical properties in response to specific analytes, enabling rapid and visual detection. The emerging applications of TMDC-based colorimetric sensors span diverse fields, including environmental monitoring, healthcare, and industrial processes. The sensors exhibit high sensitivity, selectivity, and real-time response, making them ideal candidates for detecting various target analytes. Furthermore, their integration with complementary technologies such as microfluidics, can facilitate the development of on-site and point-of-care applications. This work highlights the interdisciplinary significance of nanostructured TMDC-based colorimetric sensors and underscores their potential contributions to addressing contemporary challenges in sensing technology.

An ultrawide-range photochromic molecular fluorescence emitter

Photocontrollable luminescent molecular switches capable of changing emitting color have been regarded as the ideal integration between intelligent and luminescent materials. A remaining challenge is to combine good luminescence properties with wide range of wavelength transformation, especially when confined in a single molecular system that forms well-defined nanostructures. Here, we report a π-expanded photochromic molecular photoswitch, which allows for the comprehensive achievements including wide emission wavelength variation (240 nm wide, 400–640 nm), high photoisomerization extent (95%), and pure emission color (<100 nm of full width at half maximum). We take the advantageous mechanism of modulating self-assembly and intramolecular charge transfer in the synthesis and construction, and further realize the full color emission by simple photocontrol. Based on this, both photoactivated anti-counterfeiting function and self-erasing photowriting films are achieved of fluorescence. This work will provide insight into the design of intelligent optical materials.

Monodisperse Manganese-Vanadium-Oxo Clusters with Extraordinary Lithium Storage.

Although possessing well-defined nanostructures and excellent multi-electron redox properties, polyoxometalate clusters have poor intrinsic electrical conductivity and are prone to aggregation due to large surface energy, which makes them difficult to be fully utilized when applying as electrode materials for lithium-ion batteries. In this paper, monodisperse K7MnV13O38 (MnV13) clusters are achieved by rationally utilizing nano-sized high conductive carbon dots (CDs) as stabilizers. Benefiting from the fully exposed redox sites of MnV13 clusters (high utilization rate) and sufficient interfaces with carbon dots (extra interfacial energy storage), the optimized MnV13/10CDs anode delivers a high discharge capacity up to 1348 mAh g-1 at a current density of 0.1 A g-1 and exhibits superb rate/cycling capabilities. Density functional theory (DFT) calculations verify that ionic archway channels are formed between MnV13 and CDs, eliminating the bandgap and greatly improving the electron/ion conductivity of MnV13 and CDs. This paper paves a brand-new way for synthesis of monodisperse clusters and maximization of extra interfacial energy storage.

Co-Assembled Supramolecular Organohydrogels of Amphiphilic Zwitterion and Polyoxometalate with Controlled Microstructures.

The organization of modifiable and functional building components into various superstructures is of great interest due to their broad applications. Supramolecular self-assembly, based on rationally designed building blocks and appropriately utilized driving forces, is a promising and widely used strategy for constructing superstructures with well-defined nanostructures and diverse morphologies across multiple length scales. In this study, two homogeneous organohydrogels with distinct appearances were constructed by simply mixing polyoxometalate (phosphomolybdic acid, HPMo) and a double-tailed zwitterionic quaternary ammonium amphiphile in a binary solvent of water and dimethyl sulfoxide (DMSO). The delicate balance between electrostatic attraction and repulsion of anionic HPMo clusters and zwitterionic structures drove them to co-assemble into homogeneous organohydrogels with diverse microstructures. Notably, the morphologies of the organohydrogels, including unilamellar vesicles, onion-like vesicles, and spherical aggregates, can be controlled by adjusting the ionic interactions between the zwitterionic amphiphiles and phosphomolybdic acid clusters. Furthermore, we observed an organohydrogel fabricated with densely stacked onion-like structures (multilamellar vesicles) consisting of more than a dozen layers at certain proportions. Additionally, the relationships between the self-assembled architectures and the intermolecular interactions among the polyoxometalate, zwitterionic amphiphile, and solvent molecules were elucidated. This study offers valuable insights into the mechanisms of polyoxometalate-zwitterionic amphiphile co-assembly, which are essential for the development of materials with specific structures and emerging functionalities.