Pure cubic ZrO2 nanoparticles by thermolysis of a new precursor

Thermoplastic PHB-Reinforced Chitosan Piezoelectric Films for Biodegradable Pressure Sensors

Flexible and wearable pressure sensors have attracted significant attention in the fields of smart medicine and human health monitoring. Nevertheless, the design and fabrication of degradable disposable pressure sensors still face urgent challenges. Herein, we fabricated poly(3-hydroxybutyrate) (PHB)-reinforced chitosan (CS) piezoelectric films for intelligent sensors through a simple, low-cost, and environmentally friendly roll-forming method. The results show that PHB doping successfully increased the effective piezoelectric coefficient of the chitosan-based film from 40.12 to 49.38 pm/V (a 23% increase). Simultaneously, the pressure sensor based on the CS/PHB film exhibited excellent response sensitivity (484 mV/kPa) and a wide linear response range (0-130 kPa), which could be used as haptic sensors and motion monitoring sensors for the fast response to human motion signals. Additionally, the CS/PHB film could be completely degraded within 18 days in a natural soil environment, demonstrating outstanding degradability. Therefore, chitosan-based piezoelectric films with excellent biodegradability and piezoelectric characteristics have been successfully fabricated in this work, which will promote the innovative development of green chitosan-based electronic devices and disposable pressure sensors.

Impact of samarium on magnetic and optoelectronic properties of magnesium-based MgSm2X4 (X = S and Se) spinels for spintronics

Investigating novel compounds has become necessary due to the need for sophisticated materials in optoelectronic devices and spintronics. Because of their unique properties, magnesium-based spinels MgSm2X4 (X = S and Se) are very promising for these applications. We used the spin-polarized PBEsol for structural properties and the PBEsol functional for mechanical behavior, both using the WIEN2k code. Both compounds' stability in the magnetic and non-magnetic phases was validated by the Birch-Murnaghan equation of state, and their stability in the cubic phase was verified by the Born stability criterion. Their ductile character was shown by the computation of Pugh's ratio and Poisson ratio. Both MgSm2S4 and MgSm2Se4 display metallic behavior in the spin-up channel and semiconducting behavior in the spin-down channel, indicating a half-metallic nature, according to TB-mBJ potential calculations. With total magnetic moments of 20 μB, both materials showed ferromagnetic properties. Samarium ions contributed 5.27 μB for MgSm2S4 and 5.34 μB for MgSm2Se4. Furthermore, we computed optical parameters in the energy range of 0 to 15 eV, such as absorption, extinction coefficient, reflectivity, dielectric function, and refractive index. Our results demonstrate the potential of MgSm2X4 spinels for future technological developments by revealing their prospective optoelectronic and spintronic applications.

Enhancing oil-water emulsion separation via synergistic filtration using graphene oxide-silver oxide nanocomposite-embedded polyethersulfone membrane

This study introduces an innovative approach for enhancing oil-water emulsion separation using a polyethersulfone (PES) membrane embedded with a nanocomposite of graphene oxide (GO) and silver oxide (AgO). The composite membrane, incorporating PES and polyvinyl chloride (PVC), demonstrates improved hydrophilicity, structural integrity and resistance to fouling. Physicochemical characterization confirms successful integration of GO and AgO, leading to increased tensile strength, porosity and hydrophilicity. Filtration tests reveal substantial improvements in separating various oils from contaminated wastewater, with the composite membrane exhibiting superior efficiency and reusability compared to pristine PES membranes. This research contributes to the development of environmentally friendly oil-water separation methods with broad industrial applications.

Tailored Covalent Organic Framework Platform: From Multistimuli, Targeted Dual Drug Delivery by Architecturally Engineering to Enhance Photothermal Tumor Therapy

Engineering bulk covalent organic frameworks (COFs) to access specific morphological structures holds paramount significance in boosting their functions in cancer treatment; nevertheless, scant effort has been dedicated to exploring this realm. Herein, silica core-shell templates and multifunctional COF-based reticulated hollow nanospheres (HCOFs) are novelly designed as a versatile nanoplatform to investigate the simultaneous effect of dual-drug chemotherapy and photothermal ablation. Taking advantage of the distinct structural properties of the template, the resulting two-dimensional (2D) HCOF, featuring large internal voids and a peripheral interconnected mesoporous shell, presents intriguing benefits over its bulk counterparts for cancer treatment, including a well-defined morphology, an outstanding drug loading capability (99.6%) attributed to its ultrahigh surface area (2087 m2/g), great crystallinity, improved tumor accumulation, and an adjustable drug release profile. After being loaded with hydrophilic doxorubicin with a remarkable loading capacity, the obtained drug-loaded HCOFs were coated with gold nanoparticles (Au NPs) to confer them with three properties, including pore entrance blockage, active-targeting capability, and improved biocompatibility via secondary modification, besides high near infrared (NIR) absorption for efficient photothermal hyperthermia cancer suppression. The resultant structure was functionalized with mono-6-thio-β-cyclodextrin (β-CD) as a second pocket to load docetaxel as the hydrophobic anticancer agent (combination index = 0.33). The dual-drug-loaded HCOF displayed both pH- and near-infrared-responsive on-demand drug release. In vitro and in vivo evaluations unveiled the prominent synergistic performance of coloaded HCOF in cancer elimination upon NIR light irradiation. This work opens up a new avenue for exciting applications of structurally engineered HCOFs as hydrophobic/hydrophilic drug carriers as well as multimodal treatment agents.

High stability and selectivity of butterfly pea flower extract-NiAl LDH-based catalysts in the tetracycline degradation

Layered double hydroxide (LDH) is an applicable material that can be modified in various ways. Modifications using natural extracts fulfill the principles of "green chemistry." The preparation of butterfly pea flower extract (BPE)-modified NiAl LDH was completed using the calcination and restacking method. The characteristics of the prepared composites were identified through analysis of functional groups, crystal phase, bandgap energy, surface area and surface morphology. Fourier transform-infrared (FT-IR) characterization revealed that the active group of the catalyst is -OH except for NiAl layered double oxide (LDO), which has the metal oxide-like functional groups. X-ray diffraction patterns expressed a typical layered material structure of NiAl LDH dan NiAl LDH-BPE, but not for NiAl LDO and NiAl LDO-BPE. Introducing BPE into NiAl LDH and NiAl LDO effectively decreased the bandgap energy and changed the surface morphology. The prepared catalysts were applied in a batch system with pH 5 to degrade tetracycline (TC). NiAl LDO demonstrated the highest activity as a catalyst in TC degradation, with a 93.61% degradation rate. In contrast, NiAl LDO-BPE demonstrated the highest structural stability in TC degradation and repeated use, with an initial degradation percentage of 82.58% and a fifth regeneration percentage of 71.4%.

Synergistic effects of hybrid microfibers on mechanical, thermal, and microstructural characterization of nanocomposites

The use of geopolymers (GP) in cementitious composites provides a solution to reduce the significant carbon emissions associated with conventional cement production, thereby advancing environmentally friendly concrete construction practices. The promise of hybrid fiber-reinforced fly ash (FA)-based GP (HFGP) composites that combine microfibers and nanoparticles has not yet been fully comprehended. This research aims to enhance the mechanical and microstructural properties of HFGP blends by varying the proportion of nano calcium carbonate ( n - C a C O 3 ). The production of HFGP involved the use of two types of fibers: 1% carbon fibers and 0.5% basalt fibers. To achieve HFGP blends with a consistent fiber ratio, we incorporated four different levels of n - C a C O 3 , comprising 1%, 2%, 3%, and 4% of the mixture. The analysis of fractured samples encompassed microstructural and mineralogical characterization, which was conducted using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The results unveiled that the HFGP blend containing 3% n - C a C O 3 exhibited the highest levels of hardness, compressive strength, toughness modulus, and flexural strength while the use of 2% n - C a C O 3 produced the highest results for fracture toughness and impact strength. SEM analysis illustrated that n - C a C O 3 had a significant positive impact on the microstructure of GP. A considerable rise in hump intensity between 20 and 40 °C ( 2 θ ) was also seen in the XRD examination, indicating that calcium silicate hydrate (CSH) had formed after the primary binder, such as sodium aluminosilicate hydrate (NASH), had been present. The stretching of O-H bonds in water molecules was also seen in the HFGP spectra at 3399, 3436, 3436, and 3438 cm-1. Due to the higher water content in the HFGP network, which may influence the material's strength, these bands were more apparent and larger in specimens with additions of nanoparticles and hybrid fibers.

Nitrogen-doped metal-free granular activated carbons as economical and easily separable catalysts for peroxymonosulfate and hydrogen peroxide activation to degrade bisphenol A

The fabrication of low-cost, highly efficient, environmentally friendly, and easily separable metal-free heterogeneous catalysts for environmental remediation remains a challenge. In this study, granular nitrogen-doped highly developed porous carbons with a particle size of 0.25-0.30 mm were prepared by preoxidation and subsequent NH3 modification of a commercially available coconut-based activated carbon, and used to activate peroxymonosulphate (KHSO5) or hydrogen peroxide (H2O2) to degrade bisphenol A (BPA). The nitrogen-doped carbon (ACON-950) prepared by NH3 modification at 950 °C, with the addition of only 0.15 g/L could remove 100% of 50 mg/L BPA in 150 min, and more than 90% of the removed BPA was due to degradation. The removal rates of total organic carbon of ACON-950/KHSO5 and ACON-950/H2O2 systems reached 60.4% and 66.2% respectively, indicating the excellent catalytic activity of ACON-950. The reaction rate constant was significantly positively correlated with the absolute content of pyridinic N (N-6) and graphitic N (N-Q) and negatively and weakly positively correlated with pyrrolic N (N-5) and defects. Quenching experiments combined with electron paramagnetic resonance demonstrated that singlet oxygen was the dominant reactive oxidative species for BPA degradation. ACON-950 was characterized before and after the degradation reaction using N2 adsorption-desorption analyzer, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results confirmed the prominent contribution of both the N-6 and N-Q to the catalytic performance of nitrogen-doped carbons. The reusability of ACON-950 and its application in actual water bodies further demonstrated its remarkable potential for the remediation of organic pollutants in wastewater.

Green synthesis of nanomaterials by using plant extracts as reducing and capping agents

An alternative method to conventional synthesis is examined in this review by the use of plant extracts as reducing and capping agents. The use of plant extracts represents an economically viable and environmentally friendly alternative to conventional synthesis. In contrast to previous reviews, this review focuses on the synthesis of nano-compounds utilizing plant extracts, which lack comprehensive reports. In order to synthesize diverse nanostructures, researchers have discovered a sustainable and cost-effective method of harnessing functional groups in plant extracts. Each plant extract is discussed in detail, along with its potential applications, demonstrating the remarkable morphological diversity achieved by using these green synthesis approaches. A reduction and capping agent made from plant extracts is aligned with the principles of green chemistry and offers economic advantages as well as paving the way for industrial applications. In this review, it is discussed the significance of using plant extracts to synthesize nano-compounds, emphasizing their potential to shape the future of nanomaterials in a sustainable and ecologically friendly manner.

Zinc Oxide Nanoclusters Encapsulated in MFI Zeolite as a Highly Stable Adsorbent for the Ultradeep Removal of Hydrogen Sulfide

Often, trace impurities in a feed stream will cause failures in industrial applications. The efficient removal of such a trace impurity from industrial steams, however, is a daunting challenge due to the extremely small driving force for mass transfer. The issue lies in an activity-stability dilemma, that is, an ultrafine adsorbent that offers a high exposure of active sites is favorable for capturing species of a low concentration, but free-standing adsorptive species are susceptible to rapidly aggregating in working conditions, thus losing their intrinsic high activity. Confining ultrafine adsorbents in a porous matrix is a feasible solution to address this activity-stability dilemma. We herein demonstrate a proof of concept by encapsulating ZnO nanoclusters into a pure-silica MFI zeolite (ZnO@silicalite-1) for the ultradeep removal of H2S, a critical need in the purification of hydrogen for fuel cells. The Zn species and their interaction with silicalite-1 were thoroughly investigated by a collection of characterization techniques such as HADDF-STEM, UV-visible spectroscopy, DRIFTS, and 1H MAS NMR. The results show that the zeolite offers rich silanol defects, which enable the guest nanoclusters to be highly dispersed and anchored in the silicious matrix. The nanoclusters are present in two forms, Zn(OH)+ and ZnO, depending on the varying degrees of interaction with the silanol defects. The ultrafine nanoclusters exhibit an excellent desulfurization performance in terms of the adsorption rate and utilization. Furthermore, the ZnO@silicalite-1 adsorbents are remarkably stable against sintering at high temperatures, thus maintaining a high activity in multiple adsorption-regeneration cycles. The results demonstrate that the encapsulation of active metal oxide species into zeolite is a promising strategy to develop fast responsive and highly stable adsorbents for the ultradeep removal of trace impurities.

g-C3N4 modified with non-precious metal Al with LSPR as an efficient visible light catalyst

The issue of water pollution has emerged as a formidable challenge, prompting a pressing need for solutions. The utilization of metal nanoparticles with surface plasmon resonance and semiconductor composite photocatalysts is regarded as a highly effective approach to solve this problem. g-C3N4 is an effective catalyst for the degradation of organic pollutants. Its photocatalytic performance is usually enhanced by the use of the noble metal Au Ag. However, the high cost of these materials limits their application. In this study, we present the synthesis of Al NPs/g-C3N4 nanocomposites using the bridging effect of ligands. The characterized of transmission electron microscopy (TEM), X-ray diffractometer (XRD) and ultraviolet-visible spectroscopy (UV-Vis) proved that Al NPs/g-C3N4 with a wider light absorption range were successfully synthesized. The effects of ligands, (glutathione (GSH), glutamic acid (GAG), and cysteine (CYS)), Al diameter (40 to 200 nm) and the ratio of Al to g-C3N4 (1:1 to 5:1) on the photocatalytic degradation of methylene blue (MB) by Al NPs/g-C3N4 were also evaluated. The results showed that the optimum degradation efficiency of Al NPs/g-C3N4 for MB at 5 mg/L reached 100% within 60 min, which was 11 times higher than that of pure g-C3N4. The principal analysis of Al enhancing the photocatalytic performance of g-C3N4 was studied through transient photocurrent spectroscopy (TPC), electrochemical impedance spectroscopy (EIS), and steady-state transient fluorescence spectroscopy (PL). The results confirmed that hot carriers generated by localized surface plasmon resonance (LSPR) of Al nanoparticles increase the carrier concentration. In addition, the Schottky barrier generated by Al and g-C3N4 could also improve the carrier separation rate and increase the carrier lifetime. This work is expected to solve the problem of organic wastewater treatment and lay the foundation for subsequent research on photocatalysis.

Performance and mechanism analysis of sludge-based biochar loaded with Co and Mn as photothermal catalysts for simultaneous removal of acetone and NO at low temperature

Replacing NH3 in NH3-SCR with VOCs provides a new idea for the simultaneous removal of VOCs and NOx, but the technology still has urgent problems such as high cost of catalyst preparation and unsatisfactory catalytic effect in the low-temperature region. In this study, biochar obtained from sewage sludge calcined at different temperatures was used as a carrier, and different Co and Mn injection ratios were selected. Then, a series of sludge-based biochar (SBC) catalysts were prepared by a one-step hydrothermal synthesis method for the simultaneous removal of acetone and NO in a low-temperature photothermal co-catalytic system with acetone replacing NH3. The characterization results show that heat is the main driving force of the reaction system, and the abundance of Co and Mn atoms in high valence states, surface-adsorbed oxygen, and oxygen lattice defects in the catalyst are the most important factors affecting the performance of the catalyst. The performance test results showed that the optimal pyrolysis temperature of sludge was 400 °C, the optimal dosing ratio of Co and Mn was 4:1, and the catalyst achieved 42.98% and 52.41% conversion of acetone and NO, respectively, at 240 °C with UV irradiation. Compared with the pure SBC without catalytic effect, the SBC loaded with Co and Mn gained the ability of simultaneous removal of acetone and NO through the combined effect of multiple factors. The key reaction steps for the catalytic conversion of acetone and NO on the catalyst surface were investigated according to the Mars-van Krevelen (MvK) mechanism, and a possible mechanism was proposed. This study provides a new strategy for the resource utilization of sewage sludge and the preparation of photothermal catalysts for the simultaneous removal of acetone and NO at low cost.

Folic Acid-Decorated Chitosan-PLGA Nanobiopolymers for Targeted Drug Delivery to Acute Lymphoblastic Leukemia Cells: In Vitro Studies

OBJECTIVES

This study developed a drug delivery system (DDS) using folic acid (FA)-functionalized chitosan (CS) and poly (lactic-co-glycolic acid) (PLGA) nanocarriers for targeted sodium butyrate (NB) delivery to leukemia cells (NALM6). The goal was to enhance NB's therapeutic efficacy while reducing its cytotoxicity to non-malignant cells.

METHODS

FA-CS-PLGA nanocarriers were synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Encapsulation efficiency, release kinetics, cytotoxicity, and apoptosis induction were assessed using MTT assays and flow cytometry in NALM6 cells.

RESULTS

The FA-CS-PLGA nanocarriers had a surface charge of 34.2 ± 0.12 mV and a size range of 40-60 nm. Encapsulation efficiency was 16%, with 16% of NB released within the first 4 h. MTT assays showed a reduction in leukemia cell viability to 26% after 24 h with 400 nM FA-CS-PLGA-NB, compared to over 50% viability with pure NB. The IC50 was around 300 nM. Flow cytometry revealed that FA-CS-PLGA-NB induced apoptosis in over 20% of leukemia cells, far exceeding the 5% induced by unmodified NB.

CONCLUSION

FA-CS-PLGA nanocarriers show significant promise as a targeted DDS for leukemia therapy, enhancing NB delivery to leukemia cells and improving therapeutic efficacy while minimizing off-target toxicity. These results support further in vivo studies and potential clinical applications.

S-scheme heterojunctions based on novel Sm2CeMnO6 double perovskite oxide and g-C3N4 with excellent photocatalytic dye degradation performances

It has become of utmost importance to preserve marine life and human health by protecting aquatic environments from contaminants. Therefore, using photocatalytic materials in treatment of contaminated water is a promising and innovative technique. Novel double perovskite Sm2CeMnO6 was synthesized through a modified Pechini sol-gel method. Also, urea and melamine were utilized to synthesize graphitic carbon nitride (g-C3N4). Combination of Sm2CeMnO6 and g-C3N4 produced several S-scheme heterojunction materials in diverse components ratios. Average crystallite sizes of Sm2CeMnO6 and Sm2CeMnO6/g-C3N4 (20:80) samples were calculated by Debye-Scherrer and Williamson-Hall methods to be 19.77, 22.72 nm and 42.01, 43.73 nm, respectively. The coexistence of g-C3N4 (002) with a d-spacing of 0.325 nm and Sm2CeMnO6 planes of (222), (111), and (400) with spacing values of 0.314, 0.302, and 0.294 nm, respectively, was depicted in the HR-TEM image of the Sm2CeMnO6/g-C3N4 (20:80). The estimated bandgaps for the g-C3N4, Sm2CeMnO6, and Sm2CeMnO6/g-C3N4 (20:80) were 2.70, 2.60, and 2.65 eV, respectively. Their application was investigated in photocatalytic degradation of methylene blue (MB) dye as typical pollutant. The estimated degradation pathway of MB was also provided through LC-MS analysis. Under the identical conditions, the best photocatalytic performance was found for Sm2CeMnO6/g-C3N4 (20:80) composite. Using response surface methodology (RSM), operational parameters of the photocatalytic degradation were modeled and optimized by the best composite through central composite design approach. Applying optimized parameters led to 96% degradation of MB (8 mg/L) at pH 10 under 120 min visible light irradiation (λ > 365 nm) using 0.15 g of Sm2CeMnO6/g-C3N4 (20:80) composite in 100 mL aqueous solution. Due to low intrinsic charge transfer resistance, modified Eg, and good performance in e‒/h+ pairs production, Sm2CeMnO6/g-C3N4 (20:80) nanocomposite was introduced as a promising S-scheme photocatalyst.

Hydrothermal synthesis of ZnZrO2/chitosan (ZnZrO2/CS) nanocomposite for highly sensitive detection of glucose and hydrogen peroxide

In this work, pure ZnZrO₂ and chitosan supported (ZnZrO₂/CS) nanocomposite have been synthesized at low coast by hydrothermal method. FT-IR, Micro Raman, PXRD, HR-SEM-EDAX, HR-TEM, AFM, BET and XPS were used to analyze the structural and morphological properties of the fabricated nanocomposites. The fabricated ZnZrO₂ and ZnZrO₂/CS nanocomposites were measured for their electrocatalytic activity towards glucose and hydrogen peroxide determinations. The ZnZrO₂/CS sensor exhibited wide detection range (5 μM to 5.85 mM), high sensitivity (6.78 μA mM^-1 cm^-2), LOD (2.31 μM), and long-term stability for glucose detection in alkaline solution. Also, as a multifunctional electrochemical sensor, ZnZrO₂/CS sensor exhibits excellent sensing ability towards hydrogen peroxide, with a wide dynamic range (20 μM to 6.85 mM), a high sensitivity (2.22 μA mM^-1 cm^-2), and a LOD (2.08 μM) (S/N = 3). The electrochemical measurement shows that the ZnZrO₂/CS sensor has excellent catalytic activity and a much LOD than ZnZrO₂. The modified electrode showed excellent anti interference nature. Furthermore, this ZnZrO₂/CS electrode was used to detection of glucose and H₂O₂ in human blood serum and HeLa cells respectively.

The Effect of Sulfated Zirconia and Zirconium Phosphate Nanocomposite Membranes on Fuel-Cell Efficiency

To investigate the effect of acidic nanoparticles on proton conductivity, permeability, and fuel-cell performance, a commercial Nafion^® 117 membrane was impregnated with zirconium phosphates (ZrP) and sulfated zirconium (S-ZrO₂) nanoparticles. As they are more stable than other solid superacids, sulfated metal oxides have been the subject of intensive research. Meanwhile, hydrophilic, proton-conducting inorganic acids such as zirconium phosphate (ZrP) have been used to modify the Nafion^® membrane due to their hydrophilic nature, proton-conducting material, very low toxicity, low cost, and stability in a hydrogen/oxygen atmosphere. A tensile test, water uptake, methanol crossover, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to assess the capacity of nanocomposite membranes to function in a fuel cell. The modified Nafion^® membrane had a higher water uptake and a lower water content angle than the commercial Nafion^® 117 membrane, indicating that it has a greater impact on conductivity. Under strain rates of 40, 30, and 20 mm/min, the nanocomposite membranes demonstrated more stable thermal deterioration and higher mechanical strength, which offers tremendous promise for fuel-cell applications. When compared to 0.113 S/cm and 0.013 S/cm, respectively, of commercial Nafion^® 117 and Nafion^® ZrP membranes, the modified Nafion^® membrane with ammonia sulphate acid had the highest proton conductivity of 7.891 S/cm. When tested using a direct single-cell methanol fuel cell, it also had the highest power density of 183 mW cm^-2 which is better than commercial Nafion^® 117 and Nafion^® ZrP membranes.

Effect of Zr(IV) to phosphorus ratio on U(VI) adsorption by diethylenetriamine-pentamethylene phosphate Zr(IV) hybrids

In this work, diethylenetriamine pentamethylenephosphonic acid (DTPMP) was ultilized into preparing of Zr(IV) organophosphates hybrids (Zr-DTPMP-x, x was the molar ratio of Zr(IV)/DTPMP in the synthetic process, x = 0.5, 1, 2, and 3) using a hydrothermal method. The physical and chemical properties of Zr-DTPMP-x were characterized by SEM&EDS, FT-IR, XRD, Zeta potential, XPS, TGA and contact angle analysis. Moreover, the adsorptive performances of Zr-DTPMP-x for U(VI) were investigated. The adsorption results showed that the optimum molar ratio of Zr(IV) to phosphine, pH, equilibrium time, and dosage was 0.5, 4.0, 180 min, and 10 mg, respectively. Besides, the adsorption of U(VI) was in accordance with the pseudo-second-order kinetic model and Sips isothermal model. Moreover, the adsorption capacity determined by Sips isothermal model was 181.34 mg g−1 for Zr-DTPMP-0.5. Furthermore, the adsorptive selectivity of Zr-DTPMP-0.5 for U(VI) was superior than the others. Zr-DTPMP-0.5 may be a powerful candidate for diminishing the contamination of U(VI).

The proton conductivity and mechanical properties of Nafion®/ ZrP nanocomposite membrane

Zirconium phosphates (ZrP) were incorporated into Nafion® 117 membrane by impregnating method to obtain a reduced methanol permeation and improved proton conductivity for fuel cell application. The mechanical properties and water uptake of Nafion® membrane incorporated with zirconium phosphates nanoparticles was more improvement when compared to the commercial Nafion® 117, due to the presence of phosphoric acid within the nanoparticles. The effect of ZrP nano filler on the membrane structural morphology and thermal properties were investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA) and Scanning Electron Microscopy (SEM). The improved ion conductivity and decreased methanol permeability on the nanocomposite membranes showed a great potential for fuel cell applications. The nanocomposite membrane with high tensile strength was obtained due to the well dispersed zirconium phosphates within the Nafion® matrix.

Solvothermal Preparation and Electrochemical Characterization of Cubic ZrO₂ Nanoparticles/Highly Reduced Graphene (HRG) based Nanocomposites

A single-step solvothermal approach to prepare stabilized cubic zirconia (ZrO₂) nanoparticles (NPs) and highly reduced graphene oxide (HRG) and ZrO₂ nanocomposite (HRG@ZrO₂) using benzyl alcohol as a solvent and stabilizing ligand is presented. The as-prepared ZrO₂ NPs and the HRG@ZrO₂ nanocomposite were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD), which confirmed the formation of ultra-small, cubic phase ZrO₂ NPs with particle sizes of ~2 nm in both reactions. Slight variation of reaction conditions, including temperature and amount of benzyl alcohol, significantly affected the size of resulting NPs. The presence of benzyl alcohol as a stabilizing agent on the surface of ZrO₂ NPs was confirmed using various techniques such as ultraviolet-visible (UV-vis), Fourier-transform infrared (FT-IR), Raman and XPS spectroscopies and thermogravimetric analysis (TGA). Furthermore, a comparative electrochemical study of both as-prepared ZrO₂ NPs and the HRG@ZrO₂ nanocomposites is reported. The HRG@ZrO₂ nanocomposite confirms electronic interactions between ZrO₂ and HRG when compared their electrochemical studies with pure ZrO₂ and HRG using cyclic voltammetry (CV).

Charge compensation assisted enhancement of photoluminescence in combustion derived Li+ co-doped cubic ZrO2:Eu3+ nanophosphors

Red light emitting cubic Zr_0.99Eu_0.01O₂:Li⁺ (0-9 mol%) nanoparticles are synthesized by a low temperature, self-propagating solution combustion method using oxalyl di-hydrazide (ODH) as fuel. In this study, we report systematic investigation of the effect of lithium ion (Li⁺) concentration on the structural properties and the photoluminescence of zirconia. With increasing lithium concentration, the crystallinity of the samples increases and the lattice strain decreases. The higher crystallinity is likely due to charge compensation achieved by replacing one Zr⁴⁺ ion by a Eu³⁺ and a Li⁺ ion. Scanning electron micrographs (SEM) reveal a mesoporous structure characteristic of combustion derived nanomaterials. Photoluminescence (PL) spectra show that the intensity of the red emission (606 nm) is highly dependent on Li⁺ ion concentration. Furthermore there is a promising enhancement in the associated lifetime. Upon Li⁺ doping, the PL intensity of the samples is found to increase by two fold compared to the undoped sample. Variation of PL intensity with Li⁺ concentration is attributed to the differences in probability of non-radiative recombination (relaxing). Intensity parameters (Ω₂, Ω) and radiative properties such as transition rates (A), branching ratios (β), stimulated emission cross-section (σ_e), gain bandwidth (σ_e × Δλ_eff) and optical gain (σ_e × τ) are calculated using the Judd-Ofelt theory. The calculated values suggest that in optimally co-doped samples, in addition to improved crystallinity and charge compensation, the lowering of Eu³⁺ site symmetry and the increase in the covalency of Eu-O bonding due to interstitial Li are responsible for the observed enhancement in PL intensity.

Effect of ligand on particle size and morphology of nanostructures synthesized by thermal decomposition of coordination compounds

Thermal decomposition of organometallic and various coordination compounds are known as general method to synthesize a wide range of nanostructures including metals, metal oxides and sulfides. Herein, in order to coordinate metals and prepare suitable precursor - due to the efficient role of precursor on the particle size and morphology of products - appropriate ligands will be introduced.

Influence of the protocol of fibroin extraction on the antibiotic activities of the constructed composites

The effect of the solvents for silk fibroin (SF) extraction on its antimicrobial activity was studied. Extraction protocols were performed using LiBr (SF_L) and Ajisawa’s reagent (CaCl₂:ethanol:H₂O) (SF_C). The morphological and structural characteristics of the extracted SF and their composites were assessed. Corresponding bactericidal activities against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Pseudomonas aeroginosa (ATCC 27853) were performed. The resulting solutions were either casted into films or individually incorporated into composites of silver nanoparticles (NS) embedded into chitosan fragments (Cs) through γ-irradiation. Films of SF, obtained by using the two solvents, as well as the final prepared composites of SF, NS and Cs were analyzed using XRD, FTIR, SEM, TEM and zeta potential at several pH values. The band gap values were calculated. The results proved that, although SF_C consumed shorter gelation time, yet SF_L exerted higher antibiotic activity against the tested microorganisms. Moreover, the final composites had the ability to significantly reduce the growth of these medically relevant bacteria and are, therefore, recommended as a novel natural antibacterial biomaterial for several biomedical applications.

Microwave synthesis, characterization, and photoluminescence properties of nanocrystalline zirconia

We report synthesis of ZrO₂ nanoparticles (NPs) using microwave assisted chemical method at 80°C temperature. Synthesized ZrO₂ NPs were calcinated at 400°C under air atmosphere and characterized using FTIR, XRD, SEM, TEM, BET, and EDS for their formation, structure, morphology, size, and elemental composition. XRD results revealed the formation of mixed phase monoclinic and tetragonal ZrO₂ phases having crystallite size of the order 8.8 nm from most intense XRD peak as obtained using Scherrer formula. Electron microscope analysis shows that the NPs were less than 10 nm and highly uniform in size having spherical morphology. BET surface area of ZrO₂ NPs was found to be 65.85 m²/g with corresponding particle size of 16 nm. The band gap of synthesized NPs was found to be 2.49 eV and PL spectra of ZrO₂ synthesized NPs showed strong peak at 414 nm, which corresponds to near band edge emission (UV emission) and a relatively weak peak at 475 and 562 nm.

Direct electrochemistry of glucose oxidase immobilized on ZrO2 nanoparticles-decorated reduced graphene oxide sheets for a glucose biosensor

Schematic representation of the preparation procedure of GOx–PLL/RGO–ZrO₂ composite.

Interactions of NO2 with Zr-based MOF: effects of the size of organic linkers on NO2 adsorption at ambient conditions

Zirconium-based metal organic framework (Zr-MOF), UiO-66 and UiO-67, were synthesized and used as adsorbents of NO(2) at ambient temperatures in either dry or moist conditions. The samples were characterized before and after exposure to NO(2) by X-ray diffraction, scanning electron microscopy, N(2)-adsorption at 77 K, thermal analysis, and infrared spectroscopy. The results indicate the important effect of a ligand size on the adsorption of NO(2) on Zr-MOF materials. While the large size of the 4,4-benzenebiphenyldicarboxylic acid (BDPC) ligand has a positive impact on the adsorption of NO(2) on UiO-67 in moist conditions, the opposite effect is found in dry conditions. The large pore volume of UiO-67 enhances the adsorption of moisture and formation of nitric and nitrous acids. The small pore sizes of UiO-66 favor the NO(2) removal in dry conditions via dispersive forces. Upon interaction of NO(2) molecules with the Zr-MOF in dry conditions, the bond between the organic linker and metallic oxide center is broken, leading to the formation of nitrate and nitrite species. Moreover, organic ligands also contribute to the NO(2) reactive adsorption via nitration reaction.

Tetragonal zirconia spheres fabricated by carbon-assisted selective laser heating in a liquid medium

Submicrometer-sized tetragonal zirconia spheres are synthesized by carbon-assisted selective pulsed laser heating in a liquid medium at room temperature. Sphere formation and phase transformation from the monoclinic to the tetragonal phase are only observed by laser irradiation of a colloidal solution containing raw zirconia mechanically milled with nanocarbon. This result indicates that nanocarbon, having close contact with zirconia particles, plays a very important role in forming submicrometer-sized tetragonal zirconia spheres.