Crystalline Nanoparticles Research Articles

Defect-Rich CuZn Nanoparticles for Model Catalysis Produced by Femtosecond Laser Ablation.

Femtosecond laser ablation of Cu0.70Zn0.30 targets in ethanol led to the formation of periodic surface nanostructures and crystalline CuZn alloy nanoparticles with defects, low-coordinated surface sites, and, controlled by the applied laser fluence, different sizes and elemental composition. The Cu/Zn ratio of the nanoparticles was determined by energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and selected area electron diffraction. The CuZn nanoparticles were about 2-3 nm in size, and Cu-rich, varying between 70 and 95%. Increasing the laser fluence from 1.6 to 3.2 J cm-2 yielded larger particles, more stacking fault defects, and repeated nanotwinning, as evident from high-resolution transmission electron microscopy, aided by (inverse) fast Fourier transform analysis. This is due to the higher plasma temperature, leading to increased random collisions/diffusion of primary nanoparticles and their incomplete ordering due to immediate solidification typical of ultrashort pulses. The femtosecond laser-synthesized often nanotwinned CuZn nanoparticles were supported on highly oriented pyrolytic graphite and applied for ethylene hydrogenation, demonstrating their promising potential as model catalysts. Nanoparticles produced at 3.2 J cm-2 exhibited lower catalytic activity than those made at 2.7 J cm-2. Presumably, agglomeration/aggregation of especially 2-3 nm sized nanoparticles, as observed by postreaction analysis, resulted in a decrease in the surface area to volume ratio and thus in the number of low-coordinated active sites.

Amorphous and crystalline Sb2S3 nanoparticles embedded in N/S co-doped carbon as anodes for potassium-ion batteries

Antimony trisulfide (Sb2S3) has emerged as a promising anode candidate for potassium-ion batteries (PIBs) owing to its low cost and high theoretical specific capacity. However, its large volume expansion upon K+ storage and sluggish kinetics result in poor cycling performance and rate capability. To address these challenges, rational structural design is highly desirable. Herein, we report the synthesis of amorphous and crystalline Sb2S3 nanoparticles embedded in N/S co-doped carbon composites (a-Sb2S3@NSC and c-Sb2S3@NSC) via a facile organic coating combined with subsequent carbonization and sulfidation processes. When used as a PIBs anode material, a-Sb2S3@NSC exhibits a high discharge specific capacity of 415.6 mAh g−1 after 50 cycles at 200 mA g−1 and a stable rate capability (224.8 mAh g−1 at 2 A g−1), which remarkably outperforms that of the c-Sb2S3@NSC with inferior specific capacity (311.5 mAh g−1) and poor rate capability (67.7 mAh g−1). The amorphous structure of Sb2S3 nanoparticles in a-Sb2S3@NSC provides abundant defects and structural disorder, which reduces the entropy energy and activation barrier associated with K+ incorporation, effectively facilitating the transport and storage of K+. Moreover, the synergistic interactions between amorphous Sb2S3 nanoparticles and N/S co-doped carbon can effectively improve the electron/ion reaction kinetics and buffer volume variations, thus leading to superior potassium storage performances.

Phase-Controlled Synthesis and Phase-Change Properties of Colloidal Cu-Ge-Te Nanoparticles.

Phase-change memory (PCM) technology has recently attracted a vivid interest for neuromorphic applications, in-memory computing, and photonic integration due to the tunable refractive index and electrical conductivity between the amorphous and crystalline material states. Despite this, it is increasingly challenging to scale down the device dimensions of conventionally sputtered PCM memory arrays, restricting the implementation of PCM technology in mass applications such as consumer electronics. Here, we report the synthesis and structural study of sub-10 nm Cu-Ge-Te (CGT) nanoparticles as suitable candidates for low-cost and ultrasmall PCM devices. We show that our synthesis approach can accurately control the structure of the CGT colloids, such as composition-tuned CGT amorphous nanoparticles as well as crystalline CGT nanoparticles with trigonal α-GeTe and tetragonal Cu2GeTe3 phases. In situ characterization techniques such as high-temperature X-ray diffraction and X-ray absorption spectroscopy reveal that Cu doping in GeTe improves the thermal properties and amorphous phase stability of the nanoparticles, in addition to nanoscale effects, which enhance the nonvolatility characteristics of CGT nanoparticles even further. Moreover, we demonstrate the thin-film fabrication of CGT nanoparticles and characterize their optical properties with spectroscopic ellipsometry measurements. We reveal that CGT nanoparticle thin films exhibit a negative reflectivity change and have good reflectivity contrast in the near-IR spectrum. Our work promotes the possibility to use PCM in nanoparticle form for applications such as electro-optical switching devices, metalenses, reflectivity displays, and phase-change IR devices.

Effects of TiO2 Nanoparticles Synthesized via Microwave Assistance on Adsorption and Photocatalytic Degradation of Ciprofloxacin.

In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol was used as a solvent; acetylacetone was used as a complexation moderator; and nitric acid was used as a catalyst. Four samples of titanium dioxide were synthesized from the prepared colloidal solution in a microwave reactor at a temperature of 150 °C for 30 min and at a temperature of 200 °C for 10, 20, and 30 min. The phase composition of the TiO2 samples was determined by X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Nitrogen adsorption/desorption isotherms were used to determine the specific surface area and pore size distributions using the Brunauer-Emmett-Teller (BET) method. The band-gap energy values of the TiO2 samples were determined by diffuse reflectance spectroscopy (DRS). The distribution of Ti and O in the TiO2 samples was determined by SEM-EDS analysis. The effects of adsorption and photocatalytic activity of the prepared TiO2 samples were evaluated by the degradation of ciprofloxacin (CIP) as an emerging organic pollutant (EOP) under UV-A light (365 nm). The results of the photocatalytic activity of the synthesized TiO2 nanoparticles were compared to the benchmark Degussa P25 TiO2. Kinetic parameters of adsorption and photocatalysis were determined and analyzed. It was found that crystalline TiO2 nanoparticles with the highest specific surface area, the lowest energy band gap, and the highest photocatalytic degradation were the samples synthesized at 200 °C for 10 min. The results indicate that CIP degradation by all TiO2 samples prepared at 200 °C show a synergistic effect of adsorption and photocatalytic degradation in the removal process.

Hybrid nanocomposites for enhanced photodetection: Synthesis and application of Ag2O@Graphene/Si heterojunctions

Thin silver oxide graphene (Ag2O@G) nanocomposite films were synthesized via facile spray pyrolysis and integrated into heterojunction architectures with silicon substrate. Structural characterization confirmed the successful anchoring of crystalline Ag2O nanoparticles uniformly over graphene layers with strong interfacial coupling. Optical analysis showed synergistic tuning of the band structure by hybridization, which improves light absorption. Electrical measurements showed rectification behavior of the diode and an increase in photocurrent up to milliamperes under illumination. A response time of 350 ms, a recovery time of 400 ms, stability over repeated cycles and exceptional values such as 0.39 A/W responsivity, 88 % external quantum efficiency and 4×1011 Jones detectivity at 600 nm were achieved. The nanocomposite heterojunctions utilize the superior charge mobility of graphene with the bandgap tuning of Ag2O, enabling efficient light harvesting, photogeneration, and ambipolar charge separation and transport across the multifunctional interface. Customized Ag2O@G heterostructures represent a promising material platform to drive advances in high performance photodetectors, image sensors, night vision devices and photovoltaics through the engineering of morphology, crystallinity and interfaces.

Boosting the sonodynamic performance of CoBiMn-layered double hydroxide nanoparticles via tumor microenvironment regulation for ultrasound imaging-guided sonodynamic therapy

Sonodynamic therapy (SDT), a promising strategy for cancer treatment with the ability for deep tissue penetration, has received widespread attention in recent years. Sonosensitizers with intrinsic characteristics for tumor-specific curative effects, tumor microenvironment (TME) regulation and tumor diagnosis are in high demand. Herein, amorphous CoBiMn-layered double hydroxide (a-CoBiMn-LDH) nanoparticles are presented as multifunctional sonosensitizers to trigger reactive oxygen species (ROS) generation for ultrasound (US) imaging-guided SDT. Hydrothermal-synthesized CoBiMn-LDH nanoparticles are etched via a simple acid treatment to obtain a-CoBiMn-LDH nanoparticles with abundant defects. The a-CoBiMn-LDH nanoparticles give greater ROS generation upon US irradiation, reaching levels ~ 3.3 times and ~ 8.2 times those of the crystalline CoBiMn-LDH nanoparticles and commercial TiO2 sonosensitizer, respectively. This excellent US-triggered ROS generation performance can be attributed to the defect-induced narrow band gap and promoted electrons and holes (e−/h+) separation. More importantly, the presence of Mn4+ enables the a-CoBiMn-LDH nanoparticles to regulate the TME by decomposing H2O2 into O2 for hypoxia relief and US imaging, and consuming glutathione (GSH) for protection against ROS clearance. Biological mechanism analysis shows that a-CoBiMn-LDH nanoparticles modified with polyethylene glycol can serve as a multifunctional sonosensitizer to effectively kill cancer cells in vitro and eliminate tumors in vivo under US irradiation by activating p53, apoptosis, and oxidative phosphorylation-related signaling pathways.

Implications of size dispersion on X-ray scattering of crystalline nanoparticles: CeO2 as a case study

Controlling the shape and size dispersivity and crystallinity of nanoparticles (NPs) has been a challenge in identifying these parameters' role in the physical and chemical properties of NPs. The need for reliable quantitative tools for analyzing the dispersivity and crystallinity of NPs is a considerable problem in optimizing scalable synthesis routes capable of controlling NP properties. The most common tools are electron microscopy (EM) and X-ray scattering techniques. However, each technique has different susceptibility to these parameters, implying that more than one technique is necessary to characterize NP systems with maximum reliability. Wide-angle X-ray scattering (WAXS) is mandatory to access information on crystallinity. In contrast, EM or small-angle X-ray scattering (SAXS) is required to access information on whole NP sizes. EM provides average values on relatively small ensembles in contrast to the bulk values accessed by X-ray techniques. Besides the fact that the SAXS and WAXS techniques have different susceptibilities to size distributions, SAXS is easily affected by NP–NP interaction distances. Because of all the variables involved, there have yet to be proposed methodologies for cross-analyzing data from two techniques that can provide reliable quantitative results of dispersivity and crystallinity. In this work, a SAXS/WAXS-based methodology is proposed for simultaneously quantifying size distribution and degree of crystallinity of NPs. The most reliable easy-to-access size result for each technique is demonstrated by computer simulation. Strategies on how to compare these results and how to identify NP–NP interaction effects underneath the SAXS intensity curve are presented. Experimental results are shown for cubic-like CeO2 NPs. WAXS size results from two analytical procedures are compared, line-profile fitting of individual diffraction peaks in opposition to whole pattern fitting. The impact of shape dispersivity is also evaluated. Extension of the proposed methodology for cross-analyzing EM and WAXS data is possible.

Fusion Growth and Extraordinary Distortion of Ultrasmall Metal Oxide Nanoparticles.

Ultrasmall metal oxide nanoparticles (<5 nm) potentially have new properties, different from conventional nanoparticles. The precise size control of ultrasmall nanoparticles remains difficult for metal oxide. In this study, the size of CeO2 nanoparticles was precisely controlled (1.3-9.4 nm) using a continuous-flow hydrothermal reactor, and the atomic distortion that occurs in ultrasmall metal oxides was explored for CeO2. The crystalline nanoparticles grow rapidly like droplets via coalescence, although they reach a critical particle size (∼3 to 4 nm), beyond which they grow slowly and change shape through ripening. In the initial growth stage, the ultrasmall nanoparticles exhibit disordered atomic configurations, including stacking faults. In ultrasmall CeO2 nanoparticles (<3 to 4 nm), unusual electron localization occurs on Ce 4f orbitals (Ce3+) as a result of O disordering, regardless of O vacancy concentration. This behavior differs from ordinary electron localization caused by the presence of O vacancies. The ultrasmall metal oxides have extraordinary distortion states, making them promising for use in nanotechnology applications. Furthermore, the proposed synthesis method can be applied to various other metal oxides and allows exploration of their properties.

Crystalline phase-modulated PtOx nanoparticles exhibit superior methane combustion performance and sulfur poisoning resistance: Multi-interaction regulation

Up to now, methane combustion catalysts generally suffer from issues such as poor reaction stability and susceptibility to sulfur poisoning, which have become the key factors restricting their application, so it is necessary to construct catalysts with excellent chemical stability of the active center and strong sulfur resistance. Here, we showed the crystal phase-modulated state of PtOx nanoparticles (PtOx NPs) on TiO2 and investigated their effects on the reactivity of methane catalytic combustion and anti-SO2 poisoning properties. It was found that Pt/r-TiO2 showed superior activity, stability, and resistance to SO2 poisoning. Transmission electron microscope (TEM) images showed that the PtOx NPs on the surface of r-TiO2 were much more stable than a-TiO2 for the reason that the Ostwald ripening of PtOx NPs on a-TiO2 was facilitated due to the strong metal-support interaction (MSI) between PtOx NPs and TiO2 and the low migration energy of the PtOx NPs on TiO2, while they were moderate of Pt/r-TiO2, and then the active sites were stabilized during methane combustion. The activity was controlled by the size and electronic structure of PtOx NPs, which were stable on the surface of r-TiO2 with a higher Pt4+ content, and the density functional theory (DFT) calculations further revealed the role of r-TiO2 in increasing the quantities of surface oxygen vacancies. Moreover, the SO2 tolerance of Pt/r-TiO2 was also the best among all kinds of Pt-based catalysts prepared, which was attributed to the minimal adsorption energy (Ead) of SO2 on r-TiO2, and the absence of sulfate and sulfite deposition on the Pt/r-TiO2 catalyst confirmed by TGA and in-situ DRIFTS studies on SO2 adsorption. In this research, the anti-SO2 poisoning and reaction stability were realized by adjusting the interaction between SO2, active components, and supports, which provided a new insight for the design of stable Pt-based SO2-resistant catalysts.

Direct Imaging of Radiation-Sensitive Organic Polymer-Based Nanocrystals at Sub-Ångström Resolution.

Seeing the atomic configuration of single organic nanoparticles at a sub-Å spatial resolution by transmission electron microscopy has been so far prevented by the high sensitivity of soft matter to radiation damage. This difficulty is related to the need to irradiate the particle with a total dose of a few electrons/Å2, not compatible with the electron beam density necessary to search the low-contrast nanoparticle, to control its drift, finely adjust the electron-optical conditions and particle orientation, and finally acquire an effective atomic-resolution image. On the other hand, the capability to study individual pristine nanoparticles, such as proteins, active pharmaceutical ingredients, and polymers, with peculiar sensitivity to the variation in the local structure, defects, and strain, would provide advancements in many fields, including materials science, medicine, biology, and pharmacology. Here, we report the direct sub-ångström-resolution imaging at room temperature of pristine unstained crystalline polymer-based nanoparticles. This result is obtained by combining low-dose in-line electron holography and phase-contrast imaging on state-of-the-art equipment, providing an effective tool for the quantitative sub-ångström imaging of soft matter.

Transmission Electron Microscopic and X-ray Diffraction Based Study of Crystallographic Bibliography Demonstrated on Silver, Copper and Titanium Nanocrystals: State of the Art Statical Review

This statistical review compares the crystallographic structures of functional nanocrystals composed of silver (Ag), copper (Cu) and titanium (Ti) using transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. TEM provides high-resolution imaging to directly visualize individual nanoparticles' size, internal shape and crystallinity. Statistical analysis quantifies variations in lattice parameters, crystal structure, size distributions, phase compositions, lattice strains, preferred orientation and lattice volume of these three crystalline nanomaterials. The review highlights the complementary roles of TEM and XRD in comprehensive Ag, Cu and Ti nanocrystalline materials characterization. The crystallographic functional parameters of Ag were 2θ= 38.1° (111), 44.3° (200) and 64.4° (220); for Cu crystal 43.3° (111), 50.4° (200), 74.1° (220), 89.9° (311) and 95.1° (222) and 35.1° (100), 38.4° (002), 40.2° (101), 53.0° (102), 63.0° (103), 70.7° (110), 76.2° (112), 82.3° (201) demonstrated for Ti nanocrystals. The crystallographic predominant plane or Miller indices were also revealed by selected area electron diffraction (SAED) on TEM. The FCC structure of Ag and Cu is shown in larger lattice volumes compared to the HCP structure of Ti and prefer oriented. The degree of crystallinity of Ti, Cu and Ag nanocrystalline materials was observed at 90.0%, 98.0% and 100.0% respectively. This quantitative comparison provides valuable insights into the structural property relationships in these nanocrystals, enabling rational design strategies for optimizing their performance in various functional applications.

Tailored design of pH-responsive microbeads for oral delivery of lactoferrin nanotherapeutics of colon cancer

Colorectal cancer, one of the most fatal cancer types, has an unmet need for the development of targeted oral therapeutics. To address this, we propose to engineer a multiparticulate system to enhance the efficacy of anticancer drugs for treatment of colon cancer. We have developed a dual ligand- and pH-responsive multiparticulate system for oral drug delivery to the colon. Indomethacin (IND) and quercetin (QCT) preformulated as nanosuspensions (NSps) or liquid crystalline nanoparticles (LCNPs), respectively, were co-encapsulated into pH-responsive CA/HEC-MBs microbeads via ionoptropic gelation. To enhance tumor targeting, both nanoparticles were further coated with lactoferrin (Lf), which allows binding with Lf receptors on cancerous HCT-116 cells, resulting in higher internalization and superior cytotoxicity. Among various simulated gastrointestinal fluids, the engineered CA/HEC-MBs incorporating nanoparticles successfully released the drugs only in the colon (pH 6.8). Oral administration of both LF-targeted nanostructured microbeads into DMH-induced colorectal cancer bearing mice revealed superior in vivo anti-tumor efficacy. The microbeads efficiently reduced CEA and PCNA protein levels as well as the serum levels of IL-6, IL-1, and TNF-α. Apoptosis was also upregulated, as evidenced by increased Bax/Bcl2 ratio and increased expression levels of activated caspase-3 and caspase-9. Overall, these findings suggest that orally administered LF-targeted nanoparticle-based MBs for co-delivery of QCT and IND represent a promising alternative to conventional colon cancer therapy.

Raman peak shift and broadening in crystalline nanoparticles with lattice impurities

The effect of point-like lattice impurities on nanoparticle Raman spectra is studied using both numerical and analytical methods. Particular cases of replacement atoms of various masses, vacancies, and disorder in interatomic bonds are considered. It is shown that the disorder leads not only to the broadening of optical phonon lines but also to the shift of the corresponding Raman peak. The latter can be either positive (i.e., blueshift) or negative (redshift) depending on the type of impurities. Thus there is an additional contribution to the well-known redshift that occurs due to the size-quantization (confinement) effect. Considering nanometer-sized diamond particles as a representative example, we show that the broadening and the shift are, as a rule, of the same order of magnitude. The results are discussed in the framework of the self-consistent T-matrix approach. It is argued that both effects should be considered for accurate treatment of experimental Raman spectra. Simple recipes to do so are formulated for several important cases including NV centers in nanodiamonds.

Laser-assisted chemical bath deposition of TiO2 nanoparticles for UV photodetection

Extensive research has been conducted on UV photodetectors employing titanium dioxide nanoparticles (TiO2-NPs), which exhibit numerous advantageous qualities, notably encompassing fascinating switching behaviour and strong photosensitivity. An efficient TiO2 NPs synthesis process is essential for the quality and output of photodetectors. A quick synthesis process can lead to less energy and cost consumption, sustainable production processes, increased reaction rate, and improved homogeneity of the reaction resulting high quality films with low impurities. In this study, we exhibited a simple and quick laser-assisted chemical bath deposition (LACBD) method to synthesize high crystalline TiO2 nanoparticles for UV detection. The TiO2-NPs were synthesized by irradiating the tiny area between aluminium (Al) electrodes submerged in TiO2 precursor (in situ chemical bath) with a blue laser of wavelength (460 nm), power (1 W), and deposition duration (25 minutes). UV photodetector built from TiO2-NPs with (Al/TiO2-NPs/Al)/Glass architecture was examined, and our findings proved that TiO2 synthesized by LACBD has potential UV sensing and detecting properties. TiO2-NPs were examined by FESEM, EDX, and XRD. Measurements of current-voltage, I-V and current-time, I-T were employed to analyze the (Al/TiO2-NPs/Al)/Glass UV photodetector performance. Based on the results, it proved that the synthesis method of TiO2-NPs by LACBD is a promising and viable route, resulting in satisfactory reaction yield and low contamination. The responsivity, specific detectivity, and external quantum efficiency could reach as high as 1.36e-1 A/W, 2.87e+7 Jones and 46.1 % respectively at −5 V bias voltage.

Evaluation of structural parameters of monoclinic nanocrystalline CuO and study of sunlight-driven photocatalytic dye degradation, antimicrobial and antioxidant potential

Highly pure, crystalline and spherical-shaped Copper oxide nanoparticles (NPs) have been synthesized via facile chemical coprecipitation. Various models including the Scherrer, Monshi-Scherrer, Williamson-Hall, Size-Strain Plot and Halder-Wagner method have been applied to study the crystal structure characteristics. The lattice parameters associated with the monoclinic crystal lattice of CuO NPs were estimated to be a = 4.69 Å, b = 3.41 Å, c = 5.14 Å and β = 99.87(degree), unit cell volume V = 81.35Å3 and cell density dx = 6.49 g/cm3. The photocatalytic dye degradation proficiency at 20 mg/l CuO concentration and 120 min sunlight exposure results the order of percentage dye degradation Malachite Green (88.4%) > Crystal Violet (70.8%) > Eosin Yellow (70.2%) > Methylene Blue (54.08%) dyes. The antimicrobial activity assessment was done against the broad-spectrum pathogenic microbes unveiled the exceptional microbial controlling capability of CuO NPs. Furthermore, the antioxidant activity test demonstrated the potential free radical scavenging activity of CuO NPs with an IC50 value of 47.733 µg/ml. Highlights Synthesis of pure and spherical shaped nanocrystalline CuO was done by using low cost and facile chemical coprecipitation method. XRD, FTIR, FESEM, EDX, UV-Vis, and Raman spectroscopic techniques were used for characterization purpose. The structural and crystallographic parameters of monoclinic crystal structure of CuO NPs were evaluated successfully. The photocatalytic performance of CuO NPs follow the percentage dye degradation order as MG (88.4%) > CV (70.8%) > EY (70.20%) > MB (54.08%) after 120 minutes of sunlight exposure. CuO NPs exhibit promising antifungal activity against COVID-19 associated Pulmonary Aspergillosis (CAPA) causing pathogenic fung. CuO NPs show potential DPPH free radical scavenging activity with an IC50 value of 47.733 µg/ml.

A facile cleaner approach towards the synthesis of silver-doped cardanol-based hydrophobic antimicrobial and anticorrosive polymeric coating material

This work reports the solvent, catalyst and cross-linker free green synthesis of silver (Ag)-doped cardanol-based multifunctional polymer nanocomposite (PNC) coatings. The interaction of Ag ions with the polymeric backbone and in-situ formation of nanoparticles (NP) was confirmed by various characterization techniques. The optimum curing temperature (120–160 °C) and Ag concentration (1%) required for the free-standing film/coating with durable mechanical and chemical resistant properties in acidic/basic/salt solutions was studied. The high gel content (degree of crosslinking, 98%) and thermal stability up to 345 °C endorse the formulation of a well-cross-linked polymeric film/coating. XRD (approx. 27 nm) indicated the formation of crystalline silver nanoparticles within the polymer matrix, whereas SEM and TEM explored the distribution (200–700 nm). EIS studies for three weeks in 3.5% NaCl solution showed the exceptional corrosion inhibition efficiency (98-91%) of the coatings on steel substrate. The stable coating resistance value (MΩ.cm−2) throughout the study highlights the formation of a hydrophobic barrier with good resistance against the corrosive ions. Additionally, the potent antibacterial impact against Gram-positive, and Gram-negative bacteria, and the antifungal activity of the nanocomposite were attributed to the presence of Ag in the PNC. The multifunctional properties arise from the in-situ formed nanostructure and its synergistic effect with the biopolymer matrix projects its versatile industrial application.

Effect of precursors on Cu particle distribution in g-C3N4 nanosheets towards efficient photocatalytic degradation and H2 generation

N-rich precursors govern the thermal polymerization formation of graphitic carbon nitride (g-C3N4) based catalysts towards enhanced photocatalytic performance. In this paper, Cu components were introduced in superior thin g-C3N4 nanosheets using the thermal polymerization copper acetate and bulk g-C3N4 created by different precursors including melamine, dicyandiamide, and thiourea, such as melamine-g-C3N4 (MCN), dicyandiamide-g-C3N4 (DCN), and thiourea-g-C3N4 (TCN). The performance of Cu-g-C3N4 nanosheets depended strongly on the precursors of bulk g-C3N4 samples. The well-developed Cu nanoparticles with clear lattice fringes were observed in the sample prepared using MCN (sample Cu-MCN) while the crystallinity of Cu nanoparticles became worse in the sample prepared using DCN (sample Cu-DCN). Interestingly, Cu clusters were homogeneously distributed in superior thin g-C3N4 nanosheets in the case of using TCN (sample Cu-TCN) because of S components in thiourea affected the thermal polymerization. The photocatalytic activity of Cu-TCN was drastically improved compared with other Cu-g-C3N4 samples. The photocatalytic hydrogen production rate of Cu-TCN with 1% of Cu components was 4035.6 μmol g-1 h-1. Cycle stability test indicated that sample Cu-TCN revealed high stability, in which the H2 generation rate was retained 95% of their initial value after 5 cycles. These results supply efficient approaches for the study and application of g-C3N4 based photocatalysts.

Antibacterial and anti-biofilm activities of antibiotic-free phosphatidylglycerol/docosahexaenoic acid lamellar and non-lamellar liquid crystalline nanoparticles

Infectious diseases, particularly those associated with biofilms, are challenging to treat due to an increased tolerance to commonly used antibiotics. This underscores the urgent need for innovative antimicrobial strategies. Here, we present an alternative simple-by-design approach focusing on the development of biocompatible and antibiotic-free nanocarriers from docosahexaenoic acid (DHA) that has the potential to combat microbial infections and phosphatidylglycerol (DOPG), which is attractive for use as a biocompatible prominent amphiphilic component of Gram-positive bacterial cell membranes. We assessed the anti-bacterial and anti-biofilm activities of these nanoformulations (hexosomes and vesicles) against S. aureus and S. epidermidis, which are the most common causes of infections on catheters and medical devices by different methods (including resazurin assay, time-kill assay, and confocal laser scanning microscopy on an in vitro catheter biofilm model). In a DHA-concentration-dependent manner, these nano-self-assemblies demonstrated strong anti-bacterial and anti-biofilm activities, particularly against S. aureus. A five-fold reduction of the planktonic and a four-fold reduction of biofilm populations of S. aureus were observed after treatment with hexosomes. The nanoparticles had a bacteriostatic effect against S. epidermidis planktonic cells but no anti-biofilm activity was detected. We discuss the findings in terms of nanoparticle-bacterial cell interactions, plausible alterations in the phospholipid membrane composition, and potential penetration of DHA into these membranes, leading to changes in their structural and biophysical properties. The implications for the future development of biocompatible nanocarriers for the delivery of DHA alone or in combination with other anti-bacterial agents are discussed, as novel treatment strategies of Gram-positive infections, including biofilm-associated infections.

Green synthesis and characterization of crystalline copper nanoparticles via sodium borohydride reduction towards enhanced gas sensing application

Copper nanoparticles were produced by a chemical reduction method from precursor copper sulphate using sodium borohydride as a reducing agent. Cu nanoparticles were created by the reduction of Cu2+ ions with NaBH4 in an alkaline solution. NaBH4 and CuSO4 have a molar ratio of 1.2 (6:5). CuSO4 has a concentration of 0.02 M, and 0.04 M NaBH4 was added dropwise to develop the precipitate. Further, characterizations were performed by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared (FTIR) and Ultraviolet and Visible Spectroscopy (UV–Vis). The synthesis of the pure copper nanoparticles with a cubic crystalline structure was established. The average crystallite size of copper particle size is about 56.73 nm. The values of resistivity of the Cu conductive films were measured 4.1 × 103 Ω cm, 8 0.8 × 10−2 Ω cm and 1.4 × 10−5 Ω cm at different atmospheric environments, including air, nitrogen gas, and hydrogen gas respectively.

Fabrication of bioinspired SnO2/Few layered rGO nanocomposite coating for preserving Zn metal assets in various environments

The current study inspected the effect of incorporating two nanomaterials, namely reduced graphene oxide (rGO) and Tin oxide (SnO2), synthesized by hydrothermal method, upon improving the corrosion resistance in Zinc metal plate under different electrolytes. The XRD results confirms the formation of SnO2 nanoparticles with a crystalline tetragonal structure with 23.1 and 31.89 nm crystalline size. FE-SEM images indicated that the rGO is well embedded into the SnO2 nanoparticles. The TEM images and elemental mapping show the presence of crystalline nanoparticles embedded within the layers of graphene. In addition, the corrosion resistance of both pure SnO2 and SnO2-rGO nanocomposite is assessed using electrochemical techniques. The substrate coated with nanocomposite is exposed to three distinct electrolytes utilizing a Zn metal plate. Adding reduced graphene oxide (rGO) to the composite material creates a barrier that protects against corrosion and improves the charge transfer efficiency, resulting in lower corrosion rates and increased stability. The composite's combined impact of SnO2 and rGO provides exceptional corrosion resistance and the findings lead to the development of innovative and efficient ways to prevent corrosion, thereby ensuring materials' long-lasting and dependable performance in various industrial settings.