Uniform Nanoparticles Research Articles

Supramolecular Polymer Frameworks with Controlled and Uniform Pore Apertures

AbstractPorous frameworks with controlled pore structure and tunable aperture are greatly demanded. However, precise synthesis of this kind of materials is a formidable challenge. Herein, we report the fabrication of two‐dimensional (2D) supramolecular polymer frameworks using a precisely synthesized rod‐like helical polyisocyanide as link. Four three‐arm star‐shaped polyisocyanides with the degree of the polymerization of 10, 20, 30 and 40, and having 2‐ureido‐4[1H]‐pyrimidinone (UPy) terminals were synthesized. 2D‐Crystalline polymer frameworks with apertures of 5.3, 10.1, 13.9, and 19.1 nm were respectively obtained through intermolecular hydrogen bonding interaction between the terminal Upy units. The pore aperture is dependent on the length of polyisocyanide backbone. Thus, well‐defined supramolecular polymer frameworks with controlled and uniform hexagonal pores were obtained, as proved by small‐angle X‐ray scattering (synchrotron radiation facility), atomic force microscopy, and Brunauer–Emmett–Teller analyses. The frameworks with uniform large pore aperture were used to purify nanomaterials and immobilize biomacromolecules. For instance, the membranes of the polymer frameworks could size‐fractionation of silver nanoparticles into uniform nanoparticles with very low dispersity. The frameworks with large aperture facilitated the inclusion of myoglobin and enhanced the stability and catalytic activity.

Synthesis of Multi-Metallic Alloy Nanoparticles and Electrochemical Applications on CO2 Conversion and Hydrogen Evolution Reaction

In this comprehensive research endeavor, we introduce two groundbreaking methodologies poised to reshape the landscape of nanocomposite material synthesis, unlocking unprecedented potential across a spectrum of electrochemical applications. The Joule heating method, also known as Carbothermal Shock (CTS), emerges as a remarkably simple yet highly effective technique for generating multi-metallic nanoparticles (NPs), including high-entropy alloys (HEA). The CTS process involves loading a metal precursor onto a carbon substrate and swiftly elevating the temperature through the passage of an electric current, inducing rapid thermal shock and resulting in the formation of small and uniform NPs. While the CTS method has showcased high performance in various applications, such as rechargeable energy storage systems and catalytic conversion, challenges persist in achieving optimal surface coverage of NPs, particularly for electrochemical applications. For example, metal NPs formed through the CTS method have not been used for electrocatalytic carbon dioxide (CO2) or nitrogen (N2) reduction reactions because the hydrogen evolution reaction (HER) and unwanted reactions occur on the exposed carbon substrate as a competing reactionTo overcome this challenge, we present a pioneering approach involving the utilization of partially carbonized cellulose as a novel carbon substrate. The cellulose matrix, distinguished by its unique structural characteristics, including interconnected aromatic rings and numerous edge sites, facilitates an unprecedented high surface coverage of various single and copper (Cu)-based polyelemental alloy NPs. The controlled manipulation of defect sites, such as vacancies and dangling bonds, within the carbonized cellulose plays a pivotal role in the nucleation and stabilization of metal NPs during the CTS process. The study underscores the correlation between defect sites on the carbon substrate and the resulting surface morphology of metal NPs, providing valuable insights for future advancements in nanocomposite material synthesis through the CTS method.Moreover, the cellulose-enabled high surface coverage Cu NPs exhibit remarkable potential in electrocatalytic carbon dioxide (CO2) reduction reactions. The Cu NPs on cellulose/carbon paper (Cu/cellulose/CP) demonstrated a high ethylene selectivity of 48.92% at a potential of −0.529 V versus the reverse hydrogen electrode (RHE), maintaining stability over 30 hours of reaction in a 10 M KOH electrolyte. This study presents an exciting prospect for expanding the applications of polyelemental alloy NPs synthesized via the CTS method in diverse electrochemical applications.Transitioning to the second part of the research, we explore the application of MXenes, a recently discovered family of two-dimensional materials composed of transition metal carbides and carbonitrides. These atomically thin layers exhibit a unique combination of metallic conductivity and high surface area due to their layered structure. To enhance the properties of MXenes and broaden their applications, various components, including organic small molecules, polymers, metals, and semiconducting materials, have been incorporated into their intrinsic nanostructures.However, existing methods for fabricating MXene composite hybrid materials predominantly rely on solution processing techniques, introducing challenges such as severe MXene oxidation and nanoparticle aggregation. Addressing these limitations, we introduce a revolutionary rapid Joule heating approach, a solution-free method designed to synthesize a diverse range of MXene hybrid nanocomposites. This approach minimizes MXene oxidation on the surface and ensures a uniform distribution of nanoparticles on MXene surfaces without the drawbacks of severe aggregations. It became possible to synthesize metal NPs from unary to senary combinations (including Pt, Co, Ni, Fe, Cu components) with minimal MXene oxidation through rapid heating. The ability to easily modify the precursor ratio and synthesize unlimited combinations of MXene composite hybrid nanostructures enables the modulation of material properties to achieve high performance in diverse electrochemical applications. The resulting Pt-MXene hybrid nanostructure, synthesized through this novel approach, exhibits promising electrocatalytic performance for the hydrogen evolution reaction (HER) by minimizing MXene oxidation during the synthesis process. This breakthrough method holds immense potential for a wide range of catalytic applications, where the synergistic effects of MXene composites can significantly contribute.

( General Student Poster Award Winner, 2nd Place) Template-Assisted Fabrication of Transparent SERS Sensor with Uniform Au-Ag Nanoparticle Electrodeposition

Surface-enhanced Raman spectroscopy (SERS) is a very powerful tool for analyzing molecular interactions and provides unique spectral fingerprint information about chemical bondings.[1] SERS enhances weak Raman scattering signals through surface-localized plasmon resonance (LSPR) of the plasmonic metal nanoparticles. Arbitrarily distribution of plasmonic metal nanoparticles can result in a non-uniform SERS enhancement effect (EF) and low reproducibility, which hinders the practical application of this ultra-sensitive analysis technology.[2] The development of a cost-effective, highly reliable, and highly reproducible SERS sensor with precisely controlled nanoparticle size and distribution is still a challenge.[3] Electron beam lithography (EBL) is commonly used to achieve well-controlled nanoscale patterns, which can be used as a top-down SERS sensor fabrication technique.[2] However, the time-consuming and extremely costly method makes the SERS sensor not easily accessible.In this research, we propose a template-assisted fabrication process by electrodepositing nanoparticles into nanoarrays on a transparent ITO surface. This method precisely controls the surface morphology and provides high reproducibility without relying on EBL techniques. For the fabrication process, first, a layer of sol-gel SiO2 solution was spin-coated onto the ITO surface, and an array of nano-pillars was used to imprint the nanopattern to the sol-gel solution layer, to realize the nano-ordered uniformly distributed nanoarrays. (Fig.1) For the plasmonic material, Au-Ag alloy was deposited into the nanoarray due to its high durability and high SERS EF.[4] The use of a pulse current deposition, additives, and self-assembled monolayer (SAM) was also discussed from the perspective of altering the surface property of the ITO surface, to achieve dense and smooth filling of deposits in the nanoarray. The SERS sensor fabricated was tested with Janus Green B (JGB) and demonstrated a good SERS EF and good signal uniformity. We believe this sensor is widely applicable for different systems, further optimization and application of this sensor can bring us one step closer to the quantitative analysis by SERS. The fabricated sensor should be especially useful in electrochemical reaction analysis and biomolecular sensing.[1] Fleishmann et al., Phys. Lett., 26, 163(1974)[2] Lee et al., Chemical Society reviews., 48, 731(2019)[3] Shi et al., 66, 6525(2018)[4] B. Liu et al., 55 , 117104(2016) Figure 1

Enhancing Anode Reversal Tolerance by Low-Carbon and Carbon-Free Anode Catalyst Layers for Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs), as the main hydrogen utilization device, are considered a powerful tool for accelerating a carbon-neutral society. However, durability and cost are the two main obstacles to the commercialization of PEMFCs. Specifically, the anode reversal has been extensively studied as a severe issue that deteriorates the performance and durability of PEMFCs and leads to cell failure. Commercially, iridium oxide (IrOx) or iridium black is intensively utilized as oxygen evolution reaction catalysts to fabricate reversal tolerant anodes (RTAs) despite the slight performance loss. However, previous studies concentrated on investigating the origin or phenomena during the cell-reversal, the key factors and mechanisms affecting the anti-reversal performance, and the interaction among the anode catalyst layer components are still yet to be explored.Hence, we systematically studied the performance using three typical carbon supports with three metal contents and different metal deposition orders by experiments and model calculations. First, we synthesized Ir outside Ir/Pt/C and Pt outside Pt/It/C with uniform nanoparticle size and distribution and characterized them comprehensively. A new parameter, “relative metal coverage”, is put forward to evaluate and predict the anti-reversal ability, showing that higher relative metal coverage results in a longer reversal time and lower polarization performance degradation rate. In addition, Ir outside Ir/Pt/C shows better reversal tolerance than Pt outside Pt/It/C, which has been rarely mentioned in previous studies. Further, the experimental results show that even though the metal coverage is high, the performance degradation caused by carbon corrosion is still inevitable. On this basis, we synthesized a high specific surface area conductive oxide Ti4O7 as the anode catalyst support to eliminate the adverse effects of carbon corrosion. Previously, the initial performance of Ti4O7-supported catalyst was obstructed by the disadvantaged electrical conductivity of Ti4O7. We obtain a comparable polarization performance after optimizing the Ti4O7-supported anode catalyst layer parameters by shortening the electron transfer pathway and increasing metal coverage. Typically, the Ir@IrOx/Pt/Ti4O7-fabricated RTA with low Ir loading displays approximately ten times longer reversal time (6 hours) and two orders of magnitude lower degradation rate than a conventional carbon-supported counterpart. The degradation origin of the Ti4O7-supported anodes is also studied by postmortem characterizations, pointing to the Pt oxidation caused by the formation of TiOx thin layers on the Pt surface. These two works aim to promote the development of highly durable and reversal tolerance anode and provide a bright perspective for practical high-performance, low-degradation, and cost-friendly RTA fabrication.

Surface Ammonium Ions Assisted Decoration of Monodisperse Cobalt Nanoparticles on Molybdenum Oxide Films as Efficient Electrocatalysts for Hydrogen Evolution Reaction.

The high expense associated with electrocatalysts poses a challenge to the advancement of a hydrogen-based energy economy. The utilization of nonprecious metal-based electrocatalysts that are easily prepared and cost-effective is imperative for the future sustainability of a hydrogen society. The semiconductive MoO3-x has been identified as a promising nonprecious electrocatalyst for the hydrogen evolution reaction (HER). Nevertheless, enhancing its relatively low electrocatalytic activity toward HER remains a top priority. This study illustrates the manipulation of surface ammonium ions (NH4+) to produce uniform and distinct cobalt nanoparticles (Co NPs) on active MoO3-x supports, resulting in a more effective heterostructured composite electrocatalyst for HER. The presence of NH4+ ions in the MoO3-x film was extensively examined using infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-visible colorimetric techniques. Additionally, the firmly attached NH4+ ions were employed as binding sites to precipitate Co-containing complex ions. Due to the monolayer-like adsorption of NH4+ ions, only a small quantity of Co precipitate was formed, which was subsequently electrochemically transformed into Co atoms that diffused and created well-separated uniform metallic Co nanoparticles (with an average size of less than 10 nm) on the MoO3-x film. The resulting heterostructure displays a 4.5-fold increase in current density for HER compared to the MoO3-x electrocatalyst through electrochemical assessments. The enhanced catalytic activity was ascribed to the optimized adsorption/desorption of the species involved in water reduction at the heterointerfaces and improved charge transfer rates. These nanoheterostructures hold great promise for a variety of applications in heterogeneous electrocatalysis, while the novel approach could potentially direct the creation of more heterostructures.

Harnessing the Power of Nano‐Ferroelectrics: BaTiO3/MXene (Ti3C2Tx) Composites for Enhanced Lithium Storage

Abstract2D Ti3C2Tx MXene is a desirable electrode material for advanced lithium‐ion batteries (LIBs) in the pursuit of high energy and power densities, owing to its extensive reactive area and surface‐induced pseudo‐capacitance. Here, a novel synergistic strategy for fortifying lithium storage capability is first proposed, by in‐situ anchoring BaTiO3 ferroelectric nanoparticles on few‐layered Ti3C2Tx nanosheets (BT/f‐Ti3C2Tx) using a hydrothermal method. The uniform BaTiO3 nanoparticles effectively prevent the restacking of Ti3C2Tx nanosheets, successfully deplete metastable Ti atoms, and intriguingly form a thin and well‐adhered solid electrolyte interface layer, enhancing the aggregation‐resistant, oxidation‐resistant, and electrochemical properties of Ti3C2Tx. Simultaneously, the internal electric fields, originating from the spontaneous polarization of BaTiO3 ferroelectric nanoparticles, can augment the adsorption of Li+, boosting the lithium storage capacity and reaction kinetics. The resulting composite electrode displays a remarkable charge capacity of 84 mAh g−1 at 10 A g−1, almost five times that of pristine Ti3C2Tx electrode. The excellent rate performance and cyclability make BT/f‐Ti3C2Tx composites highly attractive for LIBs. Furthermore, this synthetic approach presented here is scalable and can be extended to other Ti‐based materials. This strategy is expected to underscore the considerable potential of ferroelectric composites for integration into high‐performance LIBs.

Platinum-Ruthenium Bimetallic Nanoparticle Catalysts Synthesized Via Direct Joule Heating for Methanol Fuel Cells.

Platinum-Ruthenium (PtRu) bimetallic nanoparticles are promising catalysts for methanol oxidation reaction (MOR) required by direct methanol fuel cells. However, existing catalyst synthesis methods have difficulty controlling their composition and structures. Here, a direct Joule heating method to yield highly active and stable PtRu catalysts for MOR is shown. The optimized Joule heating condition at 1000°C over 50 microseconds produces uniform PtRu nanoparticles (6.32wt.% Pt and 2.97 wt% Ru) with an average size of 2.0 ± 0.5 nanometers supported on carbon black substrates. They have a large electrochemically active surface area (ECSA) of 239 m2 g-1 and a high ECSA normalized specific activity of 0.295mA cm-2. They demonstrate a peak mass activity of 705.9mA mgPt -1 for MOR, 2.8 times that of commercial 20 wt.% platinum/carbon catalysts, and much superior to PtRu catalysts obtained by standard hydrothermal synthesis. Theoretical calculation results indicate that the superior catalytic activity can be attributed to modified Pt sites in PtRu nanoparticles, enabling strong methanol adsorption and weak carbon monoxide binding. Further, the PtRu catalyst demonstrates excellent stability in two-electrode methanol fuel cell tests with 85.3% current density retention and minimum Pt surface oxidation after 24 h.

Optimization of Lipid-Based Nanoparticles Formulation Loaded with Biological Product Using A Novel Design Vortex Tube Reactor via Flow Chemistry.

Lipid-based nanoparticles (LNPs) is increasingly recognized for their potential in drug delivery, offering protection to hydrophobic drugs from degradation. Industrial synthesis of LNPs, exemplified by Pfizer-BioNTech and Moderna mRNA vaccines, utilizes flow chemistry or microfluidics, showcasing its scalability. This study explores the utilization of a novel design reactor, the vortex tube reactor, within flow chemistry for LNPs synthesis, aiming to optimize its conditions and compare them with batch synthesis. LNPs were synthesized using the vortex tube reactor, incorporating bovine serum albumin (BSA) as a model drug in the aqueous phase, alongside 1.2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol in the organic phase. Design of experiments (DoE), specifically Box-Behnken design, was employed to optimize parameters, including X1: the flow rate ratio (10-100 mL/min), X2: the aqueous-to-organic volumetric ratio (1:1-10:1), and X3: the number of reactor units (1-5 units). Responses evaluated encompassed physical properties and productivity. Optimized conditions were determined by minimizing particle size (Y1), polydispersity index (Y2), and zeta potential (Y3), while maximizing entrapment efficiency (Y4), drug loading (Y5), and productivity (Y5). Results indicated that optimal conditions were achieved at X1 of 100 mL/min, X2 of 5.278, and X3 of 1 unit. LNPs synthesized under these conditions exhibited favorable physical properties and productivity, with uniformity maintained across batches. The vortex tube reactor demonstrated superiority over batch synthesis, yielding smaller particles (166.23 ± 0.98 nm), more uniform nanoparticles (PDI 0.17 ± 0.01), and higher entrapment (67.75 ± 1.55%) and loading capacities (36.39 ± 0.83%), indicative of enhanced productivity (313.4 ± 12.88 mg/min). This study elucidates the potential of flow chemistry, particularly utilizing the vortex tube reactor, for large-scale LNPs formulation, offering insights into parameter relationships and advancing nanoparticle synthesis for drug delivery applications.

Sensing of nitrate/nitrite ions in aqueous medium using poly(m-aminophenol)/silver core–shell hybrid modified graphite electrode

A very facile methodology was developed for reliable sensing of nitrate/nitrite ions in the aqueous medium using poly(m-aminophenol)/silver core–shell hybrid coated graphite electrode. The hybrid consisting of a uniform silver nanoparticle core coated with a polymer shell, was synthesized by the thermal reduction of poly(meta-aminophenol) complex with silver mono-positive ions. This core–shell hybrid was fabricated on the tip of the graphite electrode by the drop-casting method and was used as a working electrode in a two electrode setup to study the sensing performance of nitrate/nitrite ions in aqueous medium. The sensitivity and limit of detection (LOD) of the sensor were determined as ∼ 190 mA mM-1cm−2 and ∼ 0.02 mM, respectively for the nitrate/nitrite anions. Very good selective response of poly(m-aminophenol)/silver core–shell hybrid towards nitrate/nitrite ions were also confirmed over the other common tested anions/cations. The mechanism of selective sensing of nitrate/nitrite by the core–shell hybrid has been explained on the basis of selective dipole interaction as well as hydrogen bonding interaction. A reliable result was verified with an accuracy of ∼ 99 ± 4 % for nitrate/nitrite ions in real water samples.

Inclusion of TAT and NLS sequences in lipopeptide molecules generates homogenous nanoparticles for gene delivery applications

PurposesThe objective of this study is to develop a versatile gene carrier based on lipopeptides capable of delivering genetic material into target cells with minimal cytotoxicity. MethodsTwo lipopeptide molecules, palmitoyl-CKKHH and palmitoyl-CKKHH-YGRKKRRQRRR-PKKKRKV, were synthesized using solid phase peptide synthesis and evaluated as transfection agents. Physicochemical characterization of the lipopeptides included a DNA shift mobility assay, particle size measurement, and transmission electron microscopy (TEM) analysis. Cytotoxicity was assessed in CHO-K1 and HepG2 cells using the MTT assay, while transfection efficiency was determined by evaluating the expression of the green fluorescent protein-encoding gene. ResultsOur findings demonstrate that the lipopeptides can bind, condense, and shield DNA from DNase degradation. The inclusion of the YGRKKRRQRRR sequence, a transcription trans activator, and the PKKKRKV sequence, a nuclear localization signal, imparts desirable properties. Lipopeptide-based TAT-NLS/DNA nanoparticles exhibited stability for up to 20 days when stored at 6–8 °C, displaying uniformity with a compact size of approximately 120 nm. Furthermore, the lipopeptides exhibited lower cytotoxicity compared to the poly-L-lysine. Transfection experiments revealed that protein expression mediated by the lipopeptide occurred at a charge ratio ranging from 4.0 to 8.0. ConclusionThese results indicate that the lipopeptide, composed of a palmitoyl alkyl chain and TAT and NLS sequences, can efficiently condense and protect DNA, form stable and uniform nanoparticles, and exhibit promising characteristics as a potential gene carrier with minimal cytotoxicity.

Nucleus-targeting Oxaplatin(IV) prodrug Amphiphile for enhanced chemotherapy and immunotherapy

Platinum(II)-based drugs (PtII), which hinder DNA replication, are the most widely used chemotherapeutics. However, current PtII drugs often miss their DNA targets, leading to severe side effects and drug resistance. To overcome this challenge, we developed a oxaliplatin-based platinum(IV) (PtIV) prodrug amphiphile (C16-OPtIV-R8K), integrating a long-chain hydrophobic lipid and a nucleus-targeting hydrophilic peptide (R8K). This design allows the prodrug to self-assemble into highly uniform lipid nanoparticles (NTPtIV) for enhanced targeting chemotherapy and immunotherapy. Subsequently, NTPtIV's bioactivity and effects were examined at diverse levels, encompassing cancer cells, 3D tumor spheres, and in vivo. Our in vitro studies show a 74% cancer cell nucleus localization of platinum drugs-3.6 times higher than that of oxaliplatin, achieving more than a ten-fold increase in eliminating drug-resistant cancer cells. In vivo, NTPtIV shows efficient tumor accumulation, leading to suppressed tumor growth of murine breast cancer. Moreover, NTPtIV recruited more CD4+ and CD8+ T cells and reduced CD4+ Foxp3+ Tregs to synergistically enhance targeted chemotherapy and immunotherapy. Overall, this strategy presents a promising advancement in nucleus-targeted cancer therapy, synergistically boosting the efficacy of chemotherapy and immunotherapy.

Full-cycle study on developing a novel structured micromixer and evaluating the nanoparticle products as mRNA delivery carriers

Achieving precise control of nanoparticle size while maintaining consistency and high uniformity is of paramount importance for improving the efficacy of nanoparticle-based therapies and minimizing potential side effects. Although microfluidic technologies are widely used for reliable nanoparticle synthesis, they face challenges in meeting critical homogeneity requirements, mainly due to imperfect mixing efficiency. Furthermore, channel clogging during continuous operation presents a significant obstacle in terms of quality control, as it progressively impedes the mixing behavior necessary for consistent nanoparticle production for therapeutic delivery and complicates the scaling-up process. This study entailed the development of a 3D-printed novel micromixer embedded with hemispherical baffle microstructures, a dual vortex mixer (DVM), which integrates Dean vortices to generate two symmetrical counter-rotating intensified secondary flows. The DVM with a relatively large mixer volume showed rapid mixing characteristics even at a flow rate of several mL min−1 and produced highly uniform lipids, liposomes, and polymer nanoparticles in a size range (50–130 nm) and polydispersity index (PDI) values below 0.15. For the evaluation of products, SARS-CoV-2 Spike mRNA-loaded lipid nanoparticles were examined to verify protein expression in vitro and in vivo using firefly luciferase (FLuc) mRNA. This showed that the performance of the system is comparable to that of a commercial toroidal mixer. Moreover, the vigorous in-situ dispersion of nanoparticles by harnessing the power of vortex physically minimizes the occurrence of aggregation, ensuring consistent production performance without internal clogging of a half-day operation and facilitating quality control of the nanoparticles at desired scales.

User-Friendly and Responsive Electrochemical Detection Approach for Triclosan by Nano-Metal-Organic Framework.

Antimicrobial resistance poses a significant challenge to public health, and is worsened by the widespread misuse of antimicrobial agents such as triclosan (TCS) in personal care and household products. Leveraging the electrochemical reactivity of TCS's phenolic hydroxyl group, this study investigates the electrochemical behavior of TCS on a Cu-based nano-metal-organic framework (Cu-BTC) surface. The synthesis of Cu-BTC via a room temperature solvent method, with triethylamine as a regulator, ensures uniform nanoparticle formation. The electrochemical properties of Cu-BTC and the signal enhancement mechanism are comprehensively examined. Utilizing the signal amplification effect of Cu-BTC, an electrochemical sensor for TCS detection is developed and optimized using response surface methodology. The resulting method offers a simple, rapid, and highly sensitive detection of TCS, with a linear range of 25-10,000 nM and a detection limit of 25 nM. This research highlights the potential of Cu-BTC as a promising material for electrochemical sensing applications, contributing to advancements in environmental monitoring and public health protection.

LASIS-Assisted Copper Nanoparticle Synthesis and Characterization, along with UV-Visible Spectroscopy

This study investigates the creation of copper nanoparticles (CuNPs) using chemical reduction and laser ablation in liquid (LASIS). UV-visible spectroscopy is used to examine the optical characteristics of the nanoparticles created by these techniques. The purpose of the study is to compare the stability, efficacy, and particle size of CuNPs produced using different techniques. When comparing the LASIS method to the chemical reduction process, Transmission Electron Microscopy (TEM) examination revealed that the former produced smaller and more uniform nanoparticles. This work demonstrates the effectiveness of both synthesis techniques, with LASIS clearly outperforming the other in the production of superior CuNPs with more control over particle size and dispersion. A thorough explanation of the chemical reduction method and LASIS used in the synthesis of copper nanoparticles is provided, and UV-visible spectroscopy is used to characterize the resulting particles.

Novel CNT/MXene composite membranes with superior electrocatalytic efficiency and durability for sustainable wastewater treatment

Self-assembled composite membranes are increasingly acknowledged for their potential in wastewater treatment due to their superior selectivity, high operational efficiency, and environmental sustainability. Nonetheless, challenges such as inadequate removal efficiencies for low molecular weight dyes and significant membrane fouling restrict their broader industrial application. To address these challenges, a structurally stable composite membrane of sodium lignosulfonate carbon nanotubes/alkalized MXene (SLS-CNT/alk-MXene) has been engineered. This membrane employs a polyethersulfone substrate pretreated with dopamine for uniform nanoparticle assembly through a layer-by-layer self-assembly technique. The manufacturing process includes hydrophilic modification of carbon nanotubes with lignosulfonate, followed by alkalization of MXene using sodium hydroxide. Performance evaluation of the M2 composite membrane, with a content ratio of SLS-CNT to alk-MXene of 4:2 by weight, revealed outstanding membrane properties. It achieved high selective permeability, with over 99 % retention efficiency for Methyl Blue and Congo Red, and a permeation flux of 51.6 L m-2h−1 bar−1. This membrane efficiently degraded various organic dyes within 1h, including Methyl Orange, Methylene Blue, Malachite Green, and Rhodamine B, and thanks to the integration of electrocatalysis with membrane separation, while maintaining a low membrane resistance of only 813 Ω. After environmentally sustainable testing, the membrane displayed excellent stability and 80 % recovery capacity, presenting a novel approach and design blueprint for enhancing clean water resources and environmental protection.

Curcumin-Assisted Synthesis of MoS2 Nanoparticles as an Electron Transport Material in Perovskite Solar Cells.

Recently, two-dimensional (2D) transition metal dichalcogenides (2D TMDs), such as molybdenum sulfide (MoS2) and molybdenum selenide (MoSe2), have been presented as effective materials for extracting the generated holes from perovskite layers. Thus, the work function of MoS2 can be tuned in a wide range from 3.5 to 4.8 eV by adjusting the number of layers, chemical composition, elemental doping, surface functionalization, and surface states, depending on the synthetic approach. In this proposed work, we attempt to synthesize MoS2 nanoparticles (NPs) from bulk MoS2 using two steps: (1) initial exfoliation of bulk MoS2 into few-layer MoS2 by using curcumin-cholesteryl-derived organogels (BCC-ED) and curcumin solution in ethylene diamine (C-ED) under sonication; (2) ultrasonication of the subsequently obtained few-layer MoS2 at 60-80 °C, followed by washing of the above chemicals. The initial treatment with the BCC-ED/C-ED undergoes exfoliation of bulk MoS2 resulted in few-layer MoS2, as evidenced by the morphological analysis using SEM. Further thinning or reduction of the size of the few-layer MoS2 by prolonged ultrasonication at 60-80 °C, followed by repeated washing with DMF, resulted in uniform nanoparticles (MoS2 NPs) with a size of ~10 nm, as evidenced by morphological analysis. Since BCC-ED and C-ED produced similar results, C-ED was utilized for further production of NPs over BCC-ED owing to the ease of removal of curcumin from the MoS2 NPs. Utilization of the above synthesized MoS2 NPs as an ETL layer in the cell structure FTO/ETL/perovskite absorber/spiro-OMeTAD/Ag enhanced the efficiency significantly. The results showed that MoS2 NPs as an ETL exhibited a power conversion efficiency (PEC) of 11.46%, a short-circuit current density of 18.65 mA/cm2, an open-circuit voltage of 1.05 V, and a fill factor of 58.66%, at the relative humidity of 70 ± 10% (open-air conditions) than that of the ED-treated MoS2 devices without curcumin. These results suggest that the synergistic effect of both curcumin and ED plays a critical role in obtaining high-quality MoS2 NPs, beneficial for efficient charge transport, lowering the crystal defect density/trap sites and reducing the charge recombination rate, thus, significantly enhancing the efficiency.

Preparing uniform supported Pd-Ni catalysts with citrate-assisted impregnation

Bimetallic supported catalysts can show synergistic effects compared to their monometallic constituents. However, it is challenging to produce bimetallic catalysts with a uniform nanoparticle distribution over the support, while ensuring each nanoparticle contains both metals. A promising strategy is to use impregnation precursors that facilitate uniform distribution of both metals over a support. In this work, citrate-based precursors were studied to prepare bimetallic Pd-Ni nanoparticles supported on SBA-15 mesoporous silica. Amongst others, cryo-electron microscopy demonstrated the excellent distribution of Ni citrate precursor after drying. Co-impregnation with Ni citrate precursor and Pd(OAc)2 or Pd(NH3)4(NO3)2 produced well-distributed Pd-Ni nanoparticles with a narrow particle size distribution. Extensive characterization with STEM-EDX, EXAFS and TPR showed that the type of Pd precursor controlled the Pd to Ni nanoscale intimacy. CO2 hydrogenation experiments demonstrated that increasing Pd-Ni intimacy decreased the activity. Our strategy to produce uniform Pd-Ni nanoparticles using citric acid is relevant also for other bimetallic systems.

Effect of secondary metabolites from several leaf extracts on the green synthesized-ZnO nanoparticles

This study explores a green synthesis approach for zinc oxide nanoparticles (ZnO NPs) using eco-friendly leaf extracts from mango (Mangifera indica), kapok (Ceiba pentandra), and oil palm (Elaeis guineensis Jacq.) trees. The research investigates the effect of the extracts' secondary metabolites on the synthesized ZnO NPs. Qualitative analysis identified the presence of alkaloids, phenols, steroids, and saponins in varying concentrations within each extract. ZnO nanoparticles were successfully synthesized using all three extracts, confirmed by FT-IR spectroscopy with a characteristic Zn–O peak at 416.3 cm−1. XRD analysis revealed the crystalline structure of the nanoparticles, with an additional peak in ZnO_CPLE suggesting potential impurities. SEM images demonstrated the influence of secondary metabolites on particle size and morphology. ZnO_EGLE, containing both phenols and saponins, exhibited the smallest and most uniform nanoparticles (43.3 nm) compared to ZnO_CPLE (94.5 nm) and ZnO_MILE (74.9 nm). TEM analysis further supported these findings, highlighting the crucial role of phenols and saponins as capping agents in controlling particle size and agglomeration. This research suggests a promising green synthesis route for ZnO NPs using these leaf extracts, potentially tailoring particle properties based on the specific secondary metabolite profile.

Willow catkins-assisted synthesis of ZnFe2O4/ZnO hetero-tubes for chemiresistive dibutylamine sensors operated at 130 °C

The chemiresistive sensors have enabled the sensing of diverse organoamines, but the low-temperature detection of highly carcinogenic and combustible dibutylamine (DBA) has not been achieved to date. Herein, based on the concept of waste reuse and sustainable development, the discarded willow catkins were served as biotemplates and soaked into zinc or iron nitrates and their mixed solution. The above precursors were calcined at 500 °C in the air to controllably synthesize two homo-tubes and two ZnFe2O4/ZnO hetero-tubes, all of which are assembled by uniform nanoparticles. Among, the 1.25 at% ZnFe2O4/ZnO hetero-tubes possess uniform mesoporous distribution, high content of adsorbed oxygen species, and catalytic sites of high-valent Fe4+ Lewis acid, thus realizing the first metal oxide-based sensor with excellent trace DBA sensing at low temperature. The 1.25 at% ZnFe2O4/ZnO sensor exhibits high response of 79–100 ppm DBA at low 133 °C, which is 1.4, 1.8 and 2.3 times higher than those of 3.2 at% ZnFe2O4/ZnO, ZnO and ZnFe2O4 tubes, respectively. Furthermore, it also behaves rapid response kinetics (11 s∼10 ppm), good humidity resistance, reliable long-term stability (60 days), and the ability to actually detect prometryn herbicide. In addition, its response mechanism for the enhanced DBA sensing was investigated.

Pathogen-Mimicking Nanoparticles Based on Rigid Nanomaterials as an Efficient Subunit Vaccine Delivery System for Intranasal Immunization.

Despite the safety profile of subunit vaccines, the inferior immunogenicity hinders their application in the nasal cavity. This study introduces a novel antigen delivery and adjuvant system utilizing mucoadhesive chitosan-catechol (Chic) on silica spiky nanoparticles (Ssp) to enhance immunity through multiple mechanisms. The Chic functionalizes the Ssp surface and incorporates with SARS-CoV-2 spike protein receptor-binding domain (RBD) and toll-like receptor (TLR)9 agonist unmethylated cytosine-guanine (CpG) motif, forming uniform virus-like nanoparticles (Ssp-Chic-RBD-CpG) via electrostatic and covalent interactions. Ssp-Chic-RBD-CpG, mimicking the morphology and function of inactive virions, effectively prolongs the retention time of RBD in the nasal mucosa by 3.92-fold compared to RBD alone, enhances the maturation of dendritic cells (DCs), and facilitates the antigen trafficking to the draining lymph nodes, which subsequently induces a stronger mucosal immunity. Mechanistically, the enhanced chemokine chemokine (C-C motif) ligand 20 (CCL20)-driven DCs recruitment and maturation by Ssp-Chic-RBD-CpG are evidenced by a cell co-culture model. In addition, the overexpression of TLR4/9 and activation of MYD88/NF-κB signaling pathway in activation of DCs are observed. Proof of principle is obtained for RBD, but similar delivery mechanisms can be applied in other protein-based subunit vaccines as well when intranasal administration is needed.