As-prepared Nanocomposites Research Articles

Newly-development of synthetic MnCO3 and MnO2 precipitate through biologically-induced mineralization for effective adsorption of As(V) in aqueous solution

As(V) is becoming one of the dangerous and toxic chemicals causing the global issue of water pollution. Among several synthesis processes of adsorbent, biomineralization method has shown good potential. This study presented the biologically-induced synthetic Manganese Carbonate Precipitate (BISMCP) through biologically-induced mineralization method and formation change of BISMCP material after calcination process which is becoming MDSMCP. Herein, the potential ability of BISMCP and MDSMCP was performed for removal of As(V) in an aqueous solution. Characterization results showed both materials were successfully synthesized by the biomineralization process. TGA analysis showed the phase transition from MnCO3 to MnO2 significantly at 200–450 ºC. The BET surface area of the as-prepared nanocomposites was found to be 109.006 m2/g (BISMCP) and 91.672 m2/g (MDS-300). EDX analysis showed the elements in the crystal BISMCP and MDSMCP were Mn, C, and O. XRD result of BISMCP and MDSMCP determined the crystal structure, which are close to rhodochrosite (MnCO3) and pyrolusite (MnO2), respectively. Effects of pH, contact time, and varying pollutant concentration were studied in detail. The pHPZC value of BISMCP and MDS-300 was 5.5 and 1.50, respectively. According effect of pH, BISMCP and MDS-300 had better adsorption capacity at pH 6 and 2, respectively. The kinetic study for BISMCP and MDS-300 indicated that well fitted with pseudo-second-order (PSO). The experimental equilibrium data followed the Langmuir isotherm model with a maximum monolayer adsorption capacity of 119.331 mg/g (BISMCP) and 112.107 mg/g (MDS-300). This study implies that BISMCP and MDS-300 are potentially useful adsorbents for the adsorption of As(V).

Hybrids Composed of an Fe-Containing Wells–Dawson Polyoxometalate and Carbon Nanomaterials as Promising Electrocatalysts for the Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) is a key cathodic reaction in energy-converting systems, such as fuel cells (FCs). Thus, it is of utmost importance to develop cost-effective and efficient electrocatalysts (ECs) without noble metals to substitute the Pt-based ones. This study focuses on polyoxometalate (POM)-based ECs for ORR applications. A Wells–Dawson POM salt K7 [P2W17(FeOH2)O61].·20H2O was immobilised onto graphene flakes and multiwalled carbon nanotubes doped with nitrogen, denominated as P2W17Fe@GF_N8 and P2W17Fe@MWCNT_N8. The successful preparation of the composites was proved with various characterisation techniques, including FTIR, XPS and SEM. Both materials showed good ORR performance in an alkaline medium with similar potential onset values of ~0.84 V vs. RHE and diffusion-limiting current densities of −3.9 and −3.3 mA cm−2 for P2W17Fe@MWCNT_N8 and P2W17Fe@GF_N8, respectively. Furthermore, both composites presented low Tafel slopes (48–58 mV dec−1). Chronoamperometric tests revealed that the as-prepared nanocomposites rendered a significant improvement achieving between 90 and 94% of current retention in tolerance to methanol in comparison with Pt/C, and moderate to good long-term electrochemical stability with current retentions comprised between 68 and 88%. This work reinforces the use of POMs as important electroactive species for the preparation of alternative ORR electrocatalysts, exhibiting good activity, stability and selectivity towards the ORR in the presence of methanol.

Development of mucoadhesive Timolol loaded chitosan-nanocomposite to treat glaucoma

Timolol Maleate is an aqueous soluble β-blocker antiglaucoma drug used to suppress intraocular pressure. Several commercially available ocular formulations are not effective in delivering to the target site due to their water-soluble property and low mucoadhesiveness. Hence, there is a requirement for a highly mucoadhesive drug-loaded nanocomposite to suppress intraocular pressure with enhanced bioavailability. Herein, we have prepared a mucoadhesive Timolol-loaded graphene quantum dot-chitosan-nanocomposite to treat glaucoma in response to lysozyme, secreted in the tear fluid. The as-prepared nanocomposite has been characterized through high resolution-transmission electron microscopic, X-ray photoelectron spectroscopic, X-ray diffraction, and Fourier transform infrared spectral studies. The nanocomposite showed 93.74 % encapsulation efficiency with a loading capacity of 7.73 %. Further, 89.26 %, 95.62 %, and 99.29 % of drug release were observed from the nanocomposite in the presence of 1, 1.5, and 2 mg/mL of lysozyme. The mucoadhesion property has been confirmed by the increment in the particle size, fluorescence spectral variations, and Fourier transform infrared spectroscopic studies in the presence of mucin nanoparticles of size 291 nm. Interestingly, mucoadhesion has been demonstrated by pointing to the quenching in the luminescence of mucin. Further, in vitro biocompatibility assay on human corneal epithelial cells showed ≥80 % cell viability. Hence, this study offers the utilization of naturally secreting enzymes for drug delivery applications instead of uncontrolled pH and temperature-triggered releases.

Degradable PDA@PNIPAM-TA Nanocomposites for Temperature- and NIR light-Controlled Pesticide Release.

Controlled pesticide delivery systems offer many distinctive advantages over conventional pesticide formulations. In this work, degradable poly(N-isopropylacrylamide) (PNIPAM)-tannic acid (TA) microgels and multifunctional PDA@PNIPAM-TA nanocomposites were prepared in a high-gravity rotating packed bed reactor (RPB) for smart pesticide delivery and release. The as-prepared microgels and nanocomposites showed reversible temperature-dependent swelling/deswelling behavior and irreversible pH-induced degradation. A dynamic contact angle test suggested that the introduction of TA and PDA into the PNIPAM matrix could enhance foliar adhesion and deposition efficiency. The nanocomposites were further used for the encapsulation and delivery of imidacloprid (IMI) to protect it from rapid photolysis and improve its pest-control efficiency. Their thermoresponsive behavior as well as pesticide loading capacity could be tuned by tailoring the PNIPAM-TA shell thickness, which could be varied by the NIPAM amount. The release rate of IMI from the core/shell nanocomposites was positively correlated with environmental temperature and near-infrared (NIR) light, which was adaptive to the positive temperature-dependent toxicity correlation of IMI and the increasing trend of pests under high temperature. The cumulative release of IMI was 23.5% at 25 °C, while it was 81.2% at 40 °C after 24 h of incubation, and the release rate was greatly enhanced under NIR irradiation. The results indicated that the facile control of pesticide release could be realized by regulating environmental conditions. This work also provides an idea for using high-gravity technology to conveniently construct a smart, effective, and environmentally friendly pesticide delivery system for sustainable crop protection.

Investigation of kinetics, isotherms, thermodynamics and photocatalytic regeneration of exfoliated graphitic carbon nitride/zeolite as dye adsorbent

A novel exfoliated graphitic carbon nitride and clinoptilolite nanocomposites (Ex.g-C3N4/CP and g-C3N4/CP with a various ratios of g-C3N4 to CP) were prepared by facile method. This study evaluates the adsorption of methylene blue (MB) on the surface of synthesized adsorbents. The as-prepared composites were characterized by XRD, FT-IR, FESEM, BET and DRS. Batch experiments were carried out under various conditions, such as the amount of adsorbent and solution pH. The optimum batch experimental conditions were found under the response surface methodology. The Ex.g-C3N4/CP presented maximum removal of MB as compared to others. The removal efficiency of the as-prepared nanocomposite was significantly elevated owing to the synergistic effects. The adsorption capacities of MB (10 ppm) on Ex.g-C3N4/CP was 54.3 mg/g. The adsorption process by both composites (g-C3N4/CP and Ex.g-C3N4/CP) showed well-fitting with the Elovich kinetic model, and Langmuir isotherm. The thermodynamic study suggested that the adsorption of MB was a spontaneous and endothermic process. The reusability of g-C3N4/CP1:2 and Ex. g-C3N4/CP in removing of MB (10 ppm, pH = 9) was studied by photocatalytic regeneration under visible irradiation for three consecutive cycles. The results obtained from the experimental analyses showed that the removal of MB was easy treatment, eco-friendly, and high yield.

Fe3O4 incorporated geopolymer nanocomposites for microwave absorption: Role of size, structure, and dispersion

The demand for sustainable construction materials with outstanding microwave absorbing properties is essential to provide comprehensive protection against the harmful effects of electromagnetic (EM) radiation. Herein, a series of Fe3O4-based materials with similar shapes, including Fe3O4 nanospheres with average sizes of 10 nm (Fe3O4-10) and 400 nm (Fe3O4-400) and hollow Fe3O4 nanospheres with an average size of 400 nm (H-Fe3O4-400), were synthesized. SiO2 was coated on the surface of Fe3O4-based materials. Geopolymer (GP) nanocomposites containing different Fe3O4-based materials were prepared. The roles of the size, structure, and dispersion of Fe3O4-based materials on the microwave absorption and compression properties of GP nanocomposites were comprehensively explored. Owing to the hollow structure and heterointerface formed, GP nanocomposites containing H-Fe3O4-400 displayed outstanding microwave absorption performance with a minimum reflection loss (RLmin) of −39.3 dB at 2.2 mm and an effective absorption bandwidth (EAB) of 4.8 GHz. More importantly, radar cross section (RCS) simulation was conducted to demonstrate the outstanding microwave attenuation capability of H-Fe3O4-400/GP nanocomposites in a real service environment. The results showed that the performance of GP nanocomposites was more competitive than that of other similar microwave absorbing construction materials. Furthermore, the compression tests showed that the introduction of H-Fe3O4-400 decreased the compressive strength of the GP nanocomposites from 37.87 to 31.62 MPa, while the presence of SiO2 enhanced interfacial load transfer, increasing the compressive strength to 37.16 MPa. The overall results validated that the as-prepared GP nanocomposites can be a potential candidate for use in construction areas where microwave absorption is essential.

Fe3O4 nanochips loaded MXenes/g-C3N4 nanocomposite for ultrasensitive electrochemical detection of zinc (II), cadmium (II), lead (II), copper (II) and mercury (II) metal ions

The present work demonstrates a highly sensitive and efficient nanosensor for the simultaneous detection of zinc (II), cadmium (II), lead (II), copper (II) and mercury (II) metal ions using Ti3C2/Fe3O4/g-C3N4 nanocomposite. The Ti3C2/Fe3O4/g-C3N4 nanocomposite was prepared using co-prcepitation method followed by ultrasonication treatment containing Ti3AlC2, ferrous sulfate, ferric chloride and melamine as precursors. The as-prepared nanocomposites were successfully examined using XRD, FTIR, SEM and cyclic voltammetric techniques. Differential pulse anodic stripping voltammetry (DPASV) technique was applied for the simultaneous detection of Zn (II), Cd (II), Cu (II), Pb (II) and Hg (II) ions. The electrochemical variables including pH of the solution, amount of Ti3C2/Fe3O4/g-C3N4 on the GCE surface, supporting electrolyte and deposition time were optimized to get maximum sensitivity. Under optimal conditions, Ti3C2(HF)/Fe3O4/g-C3N4 sensor exhibited excellent performance for Zn (II), Cu (II), Cd (II), Pb (II) and Hg (II) in a range from 0.5 to 0.005 μM with detection limits 0.26 nM for Zn (II), 0.21 nM for Cd (II), 0.10 nM for Pb (II), 0.11 nM for Cu (II) and 0.12 nM for Hg (II) which are lower than the permissible limit recommended by the WHO guidelines. The sensor also shown outstanding selectivity in the presence of various foreign species (Ca2+, Mg2+, Na1+, Cl1-, NO31-, and 4-nitrophenol) and high resolution for simultaneous detection of Zn (II), Cd (II), Cu (II), Pb (II) and Hg (II) ions. The good electroanalytical performance and excellent selectivity and sensitivity of developed nanosensor can be attributed to the heterostructure and the coordination provided by MXene and Fe3O4/g-C3N4, resulting in enhanced interfacial charge transfer and number of adsorption sites. In addition, the developed sensor was applied for the detection of metal ions in tap water samples and satisfactory results were obtained. This study highlights a facile approach for designing MXene-supported magnetic NPs/ N containing carbon materials as sensing platform for the detection of other toxic heavy metal ions.

A rapid and efficient novel synthesis of 1,4-dioxo-1,4-dihydronaphthalen-2-yl-1,4-dihydropyridines under green conditions

1,4-Dihydropyridine scaffold has fascinated extensive interest in synthetic and medicinal chemistry due to its presence in various natural products with diverse biological activities. Herein, we report a mesoporous CeO2 doped HAp nanocomposite which was prepared and its catalytic potential in the facile synthesis of 1,4-dioxo-1,4-dihydronaphthalen-2-yl-1,4-dihydropyridine analogues. P-XRD, SEM, SEM-EDX, HRTEM, and BET techniques were utilized for the characterization of as-prepared nanocomposite. Broad substrate scope, mild reaction condition, excellent yield (93-98%) in short reaction time, use of non-toxic solvents, no usage of column chromatography are the various benefits of present synthetic route. The nano-composite was recycled and reused up to seven runs without significant loss in its catalytic activity.

Synthesis and characterization of Ag-Au loaded SiO2 nanocomposites and study of its catalytic applicability in Mannich reaction

This study, Ag-Au/SiO2 bimetal nanocomposites were used as a heterogeneous novel catalyst for microwave-assisted stereoselective synthesis of β-amino carbonyl in Mannich reaction. For this purpose, Ag-Au bimetal nanoparticles (BNPs) was prepared with the particle size lower than 30 nm and loaded on SiO2 nanospheres. These Ag-Au/SiO2 nanocomposites were synthesized via Stober method modified with the addition of colloidal bimetal nanoparticles. The as-prepared nanocomposites were characterized by several techniques including scanning electron microscopy (HR-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The catalytic performance of the synthesized Ag-Au/SiO2 for the catalysis of Mannich reaction was investigated. The present methodology found to be having several advantages, such as good yield, shorter reaction time and the reusability of the catalyst.

Hydrogen production via water electrolysis on an active electrocatalyst rGONi nanocomposite

The development of inexpensive and effective electrocatalyses are all-important for hydrogen production from water electrolysis. In this study, a facile design of a reduced graphene oxide (rGO) based electrocatalyst decorated with nickel nanoparticles is described. The voltammetric results and the hydrogen evolution reaction (HER) kinetics showed that the as-prepared nanocomposite is an effective and stable electrocatalyst for hydrogen production with a small Tafel slope of 152 mVdec-1 and long-term continuous durability (over 24 h) in 0.5 M H2SO4 solution. Also, the enhanced HER activity was confirmed by characterization results with the porous/greater electroactive surface area. The remarkable increase in electrocatalytic activity was due to the surface roughness and the synergetic chemical coupling effects between rGO and Ni nanoparticles.

Enhancement photoactivity of CuO-doped YVO4 nanocomposites toward degradation of Atrazine herbicide under visible illumination

Herbicide photocatalytic oxidation across nanostructured semiconductor-based photocatalysts demonstrated an appropriate strategy for controlling the resulting environmental problems. Developing a recyclable and efficacious photocatalyst is a challenge to overcome the semiconductor defects like instability and quick recombination. A series of CuO-YVO4 nanocomposites with different concentrations of CuO were synthesized by the surfactant sol–gel method. The different characterization techniques approved the structures and morphology of the as-prepared nanocomposites. The Atrazine degradation in water under illumination with visible light was used to assess the photocatalytic performance of the as-synthesized CuO-YVO4 nanocomposites. It demonstrates that combining CuO nanoparticles (NPs) can significantly enhance the photocatalytic activity of YVO4. The full photooxidation of Atrazine was achieved over 1.6 g/L of 15 wt% CuO-YVO4 with an outstanding rate constant of 0.0518 min−1 about 51.8 times greater than that in pristine YVO4 (0.001 min−1) and keeping recyclability of 96.5%. The maximal photodegradation efficiency of 15 wt% CuO-YVO4 is likely relevant to suppressing charge recombination with enhanced light harvesting. The Atrazine photocatalytic degradation mechanism was suggested. The results of this research will pave the way for the widespread application of oxide-vanadate semiconductor photocatalysts for the photocatalytic oxidation of herbicide contaminates in water under visible illumination.

Zeolite-supported g-C3N4/ZnO/CeO2 nanocomposite: Synthesis, characterization and photocatalytic activity study for methylene blue dye degradation

A ternary system g-C3N4/ZnO/CeO2 and its novel zeolite-supported nanocomposite were prepared and characterized using XRD, UV–Vis DRS, SEM, and PL instruments. The photodegradation efficiency of the zeolite-supported g-C3N4/ZnO/CeO2 nanocomposite for MBdye and textile processing effluent was investigated and found to be 95.2% and 72.77%, respectively. Using a zeolite-supported (STZ) composite, the influence of working parameters such as pH, initialdye amount, and catalyst dose on MBdye photodegradation was investigated. The photodegradation efficiencies of the bare ternary system and its zeolite-supported counterpart were determined to be 81.74 and 95.89%, respectively, under optimal operating circumstances. The action of several scavengers revealed that the principal active species that participated in the degradation of MB dye were •O2– and •OH. After five consecutive runs, the reusability of the supported photocatalyst was examined, and only approximately a 5% decrease was noted. For the entire as-prepared nanocomposite, the photodegradation of MB dye follows pseudo-first-order kinetics. When compared to the unitary, binary, and ternary as-synthesized nanocomposites, zeolite-supported g-C3N4/ZnO/CeO2 demonstrated a superior degradation efficiency and hence has potential applications in the photodegradation of harmful organic contaminants.

Highly-impressive performances of novel NiCo2O4/Bi2O3/Ag2ZrO3 nanocomposites in photocatalysis system, removal pathway, toxicity estimation, and antibacterial activities

BackgroundNowadays, drugs have been developed widely for the remediation of different microbial diseases. However, the presence of these compounds have influence on the water bodies. Thereupon, the preparation of inexpensive and efficient catalysts for the antibiotics degradation is important for the treatment of toxic contaminant in water. MethodsThe ternary NiCo2O4-Bi2O3-Ag2ZrO3 nanocomposite has been presented through a facile co-precipitation methods. The as-prepared nanocomposites was studied for the decomposition of metronidazole (MTN) under the visible light, and characterized by different analysis such as TEM, UV-vis, XPS, SEM, FT-IR, EIS, ESR, BET, and PL techniques. Significant findingsThe determined band gap values of Ag2ZrO3, Bi2O3, NiCo2O4 and NiCo2O4-Bi2O3-Ag2ZrO3 nanocomposites were 2.67, 2.45, 2.18 and 1.92 eV, respectively. The degradation efficiency of NiCo2O4-Bi2O3-Ag2ZrO3 under visible light displays the 100.0% decomposition attained in 80 min. The important parameters such as neutral pH, 4.0 g/L of catalyst dosage, and 5 mg/L of MTN concentration were found to be favorable for this reaction. The great recyclability attributes of the prepared catalyst were discerned after five successive cycles. The toxicity of the degraded MTN products were harmless and non-toxic. The scavenging test revealed that ·OH and ·O2− were the important radicals in the degradation of MTN by NiCo2O4-Bi2O3-Ag2ZrO3. The fabricated NiCo2O4-Bi2O3-Ag2ZrO3 was also investigated for the antimicrobial activity.

Hydrothermal Fabrication of GO Decorated Dy2WO6-ZnO Ternary Nanocomposites: An Efficient Photocatalyst for the Degradation of Organic Dye

Environmental and human health are seriously threatened by organic dye pollution. Many efforts have been made to find effective and safe methods of eliminating these contaminants. To mitigate these effects, the hydrothermal method was used to effectively generate a ternary kind of Dy2WO6-ZnO embedded in graphene oxide (DWZG) nanocomposites, which were used to degrade the pollutant. Powder X-ray diffraction (XRD) investigation confirms the crystalline character of the as-prepared DWZG nanocomposite. The Dy2WO6-ZnO composition on the graphene oxide (GO) layer is shaped like a combination of algae (Dy2WO6) and clusters (ZnO), as shown by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) investigation revealed the composition of elements and oxidation state of C, Dy, O, W and Zn elements. Methylene blue (MB) was chosen as the organic dye target for photocatalytic degradation using the produced nanocomposites. MB is degraded with a photocatalytic efficiency of 98.2% in about 30 min using a DWZG catalyst. Based on the result of the research entitled “Reactive Oxidative Species,” the primary reactive species involved in the MB degradation are photo-generated •OH and O2•− radicals. The recycle test was also successful in evaluating the catalysts’ long-term viability as well as their reusability.

Ternary Metal (Cu-Ni-Zn) Oxide Nanocomposite via an Environmentally Friendly Route.

In this work, we report the engineering of sub-30 nm nanocomposites of CuO/ZnO/NiO by using Dodonaea viscosa leaf extract. Zinc sulfate, nickel chloride, and copper sulfate were used as salt precursors, and isopropyl alcohol and water were used as solvents. The growth of nanocomposites was investigated by varying the concentrations of precursors and surfactants at pH 12. The as-prepared composites were characterized by XRD analysis and found to have CuO (monoclinic), ZnO (hexagonal primitive), and NiO (cubic) phases with an average size of 29 nm. FTIR analysis was performed to investigate the mode of fundamental bonding vibrations of the as-prepared nanocomposites. The vibrations of the prepared CuO/ZnO/NiO nanocomposite were detected at 760 and 628 cm-1, respectively. The optical bandgap energy of the CuO/NiO/ZnO nanocomposite was 3.08 eV. Ultraviolet-visible spectroscopy was performed to calculate the band gap by the Tauc approach. Antimicrobial and antioxidant activities of the synthesized CuO/NiO/ZnO nanocomposite were investigated. It was found that the antimicrobial activity of the synthesized nanocomposite increases with an increase in the concentration. The antioxidant activity of the synthesized nanocomposite was examined by using both ABTS and DPPH assays. The obtained results show an IC50 value of 0.110 for the synthesized nanocomposite compared to DPPH and ABTS (0.512), which is smaller than that of ascorbic acid (IC50 = 1.047). Such a low IC50 value ensures that the antioxidant potential of the nanocomposite is higher than that of ascorbic acid, which in turn shows their excellent antioxidant activity against both DPPH and ABTS.

β-cyclodextrin grafted multi-walled carbon nanotubes/chitosan (MWCNT/Cs/CD) nanocomposite for treatment of methylene blue-containing aqueous solutions

β-cyclodextrin (CD) was grafted with multi-walled carbon nanotubes/chitosan (MWCNTs/Cs) to obtain MWCNTs/Cs/CD nanocomposite (NC) for methylene blue (MB) adsorption from aqueous media. TEM, XRD, TGA, Raman spectra, and BET & BJH analyses were utilized to characterize and confirm the successful synthesis of as-prepared NC. MB capture was investigated by considering the parameters of pH (1.9–9.0), temperature (∼16–63 °C), sonication time (∼5–15 min), MB concentration (∼1.2–48 mg/L), and NC dose (0.03–0.26 mg). The obtained responses were then modelled using CCD, generalized regression neural network (GRNN), and least squares support vector machine (LS-SVM), of which the latter found to provide most reliable and accurate results (RMSE = 0.0235, MAE = 0.020, AAD = 0.0047, and R2 = 0.999). Moreover, the genetic algorithm-based optimization results showed that under the respective values of 7.05, 45.5 °C, 10 min, 23 mg/L, 0.12 g, MWCNTs/Cs/CD NC would be able to remove 96.75% of MB with an adsorption capacity of 603 mg/g, through different mechanisms mainly electrostatic interactions. Following from Dubinin-Radushkevich (D-R) isotherm (qs = 460.66 ± 8.9 and R2 > 0.99) and intraparticle diffusion kinetic (R2 = 0.75–0.90) models indicated a chemical adsorption mechanism. Besides, thermodynamic parameters (ΔH◦ = −66.9 kJ/mol, ΔG◦ = between −3.77 kJ/mol and −8.52 kJ/mol, and ΔS◦ = 237.1818 J/mol K) confirmed an endothermic and spontaneous nature for the adsorption. These findings along with appropriate recyclability (five times), turn the as prepared NC to a promising material in removing MB from aqueous solutions.

Green and Facile Approach for the Synthesis of ZnO/MgO Nanocomposite using Azadirachta indica Leaf Extract: Characterization and Photocatalytic Activity

In this study, biomolecules of the aqueous leaf extract of Azadirachta indica were used as a green catalyst for the synthesis of bimetallic- ZnO/MgO nanocomposites (ZM NCs). The function of biomolecules for the fabrication of biosynthesized ZM NCs was studied by FT-IR spectroscopy while the existence of both MgO and ZnO in ZM NCs was confirmed by SEM and TEM micrographs. Results of EDX spectroscopy with element mapping revealed the homogenous distribution of magnesium and zinc in the as-prepared nanocomposites. Powder XRD analysis reflects the polycrystalline nature of NCs with crystallite size ~33nm whereas XPS analysis confirmed the formation of ZnO-MgO heterojunction in ZnO/MgO NCs. In addition, biosynthesized and characterized ZMNCs were evaluated for photodegradation performance using methylene blue solution (40ppm) under visible light irradiation. The achieved degradation efficiency of ZnO/MgO NCs (95.7%) was higher compared to biosynthesized monometallic nanoparticles {ZnO (82.4% and MgO (80.1%)}.

A Modified Electrochemical Sensor Based on N,S-Doped Carbon Dots/Carbon Nanotube-Poly(Amidoamine) Dendrimer Hybrids for Imatinib Mesylate Determination.

Imatinib mesylate, an anticancer drug, is prescribed to treat gastrointestinal stromal tumors and chronic myelogenous leukemia. A hybrid nanocomposite of N,S-doped carbon dots/carbon nanotube-poly(amidoamine) dendrimer (N,S-CDs/CNTD) was successfully synthesized and used as a significant modifier to design a new and highly selective electrochemical sensor for the determination of imatinib mesylate. A rigorous study with electrochemical techniques, such as cyclic voltammetry and differential pulse voltammetry, was performed to elucidate the electrocatalytic properties of the as-prepared nanocomposite and the preparation procedure of the modified glassy carbon electrode (GCE). A higher oxidation peak current was generated for the imatinib mesylate on a N,S-CDs/CNTD/GCE surface compared to the GCE and CNTD/GCE. The N,S-CDs/CNTD/GCE showed a linear relationship between the concentration and oxidation peak current of the imatinib mesylate in 0.01-100 μM, with a detection limit of 3 nM. Finally, the imatinib mesylate's quantification in blood-serum samples was successfully performed. The N,S-CDs/CNTD/GCE's reproducibility and stability were indeed excellent.

Effective Nanocomposite Based on Bi2MoO6/MoS2/AuNRs for NIR-II Light-Boosted Photodynamic/Chemodynamic Therapy.

Bi2MoO6 (BMO) nanoparticles (NPs) have been widely used as a photocatalyst to decompose organic pollutants, but their potential for photodynamic therapy (PDT) is yet to be explored. Normally, the UV absorption property of BMO NPs is not suitable for clinical application because the penetration depth of the UV light is too small. To overcome this limitation, we rationally designed a novel nanocomposite based on Bi2MoO6/MoS2/AuNRs (BMO-MSA), which simultaneously possesses both the high photodynamic ability and POD-like activity under NIR-II light irradiation. Additionally, it has excellent photothermal stability with good photothermal conversion efficiency. The as-prepared BMO-MSA nanocomposite could induce the germline apoptosis of Caenorhabditis elegans (C. elegans) via the cep-1/p53 pathway after being illuminated by light with a wavelength of 1064 nm. The in vivo investigations confirmed the ability of the BMO-MSA nanocomposite for the induction of DNA damage in the worms, and the mechanism was approved by determining the egl-1 fold induction in the mutants that have a loss of function in the genes involved in DNA damage response mutants. Thus, this work has not only provided a novel PDT agent, which may be used for PDT in the NIR-II region, but also introduced a new approach to therapy, taking advantage of both PDT and CDT effects.

Engineering of a Hybrid g-C3N4/ZnO-W/Cox Heterojunction Photocatalyst for the Removal of Methylene Blue Dye

Robust hybrid g-C3N4/ZnO-W/Cox heterojunction composites were synthesized using graphitic carbon nitride (g-C3N4) and ZnO-W nanoparticles (NPs) and different concentrations of Co dopant. The hybrid heterojunction composites were prepared by simple and low-cost coprecipitation methods. The fabricated catalyst was explored and investigated using various characterization techniques such as FTIR, XRD, FESEM and EDX. The surface morphology of the as-prepared hybrid nanocomposites with particle sizes in the range of 15–16 nm was validated by SEM analysis. The elemental composition of the synthesized composites was confirmed by EDS analysis. Photocatalysis using a photon as the sole energy source is considered a challenging approach for organic transformations under ambient conditions. The photocatalytic activity of the heterojunctions was tested by photodegrading methylene blue (MB) dye in the presence of sunlight. The reduced band gap of the heterojunction composite of 3.22–2.28 eV revealed that the incorporation of metal ions played an imperative role in modulating the light absorption range for photocatalytic applications. The as-synthesized g-C3N4/ZnO-W/Co0.010 composite suppressed the charge recombination ability during the photocatalytic degradation of methylene blue (MB) dye. The ternary heterojunction C3N4/ZnO-W/Co0.010 composite showed an impressive photocatalytic performance with 90% degradation of MB under visible light within 90 min of irradiation, compared to the outcomes achieved with the other compositions. Lastly, the synthesized composites showed good recyclability and mechanical stability over five cycles, confirming them as promising photocatalyst options in the future.