Presence Of Sodium Borohydride Research Articles

Catalytic reduction, antibacterial, and antioxidant activities of green synthesized silver nanoparticles using Coccinea grandies (L) Voigt leaf extract

In this study, silver nanoparticles (AgNPs) were synthesized using the aqueous extract of Coccinia grandis (L) Voigt leaf (CGL) extract using microwave irradiation method and the structure was elucidated by various techniques such as UV–Visible spectroscopy, Fourier transformation infrared spectroscopy (FT-IR), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM). The UV–visible spectroscopy confirmed the formation of AgNPs and SPR band appear at 420 nm. FT-IR analysis indicated the presence of –OH and –NH functional groups from secondary molecules of CGL capping the AgNPs surface. HR-TEM revealed spherical aggregates with an average size of 29.4 nm. EDX confirmed the presence of elemental silver. XRD analysis showed that the AgNPs had a face-cantered cubic (FCC) crystal structure. The CGL-AgNPs were used as a heterogeneous catalyst to reduce RhB and CR dyes from aqueous solutions in the presence of sodium borohydride (NaBH4). The results showed that greater than 95 % of catalytic reduction can be accomplished within 9 min. The biosynthesized AgNPs demonstrated notable antioxidant activity (82.89 % in the DPPH assay) and antibacterial activity with a Zone of inhibition ranging from 9 to 11 mm. These findings suggest that CGL can be used to synthesize new, cost-effective AgNPs using an environmentally friendly approach.

Catalytically Active Gold Nanoparticles on Star Block Co-polymer Matrix: Synthesis of Nanocomposite Film Exploring the Langmuir-Blodgett Technique.

Nanocomposites with metal nanoparticles and block copolymers distributed in a stable and robust thin film are preferred for various applications. Here, synthesis of such a nanocomposite is reported, which is composed of gold nanoparticles (AuNPs) embedded in a tetronic 701 (T701) and 90R4 (T90R4) thin film matrix generated using the Langmuir-Blodgett (LB) thin film technique. Tetronics contain a monoprotonated central ethylenediamine group at pH 5 due to the presence of chloroauric acid (HAuCl4) in the subphase, along with poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) blocks, both of which have the capacity to serve as the reducing agent toward chloroaurate anion (AuCl4-). Calorimetric experiments have shown that T90R4 has a better interaction with AuCl4-, probably due to its better electrostatic interaction with AuCl4- ions due to the higher % of the hydrophilic PEO group. On the other hand, the T701-AuNP interaction turned out to be more spontaneous due to the higher hydrophobicity of T701 (higher PPO/PEO ratio). The optical properties and structure/morphology of these nanocomposites are characterized by UV-vis spectroscopy, FTIR spectroscopy, XRD, and TEM. The composite thin film has the ability to catalyze the organic electron transfer process between p-nitrophenol and p-aminophenol in the presence of sodium borohydride. A clear correlation has been found between the reaction rates and the kind of tetronic present in the nanocomposite, which acted as a matrix and stabilizer toward AuNPs.

UV light promoted dihydrolipoic acid and its alanine derivative directed rapid synthesis of stable gold nanoparticles and their catalytic activity

In general, colloidal gold nanoparticles (AuNPs) have been synthesized in heated or boiling water containing HAuCl4 precursor with sodium citrate as reducing stabilizing reagent. Although temperature plays a driving for synthesis of AuNPs, elevated temperature in thermal reduction method causes aggregation of the AuNPs. The preferential, rapid and strong binding of dihydro-lipoic acid and its derivatives on surface of AuNPs via thiol − Au chemistry promote the production of very stable AuNPs. In this study, we have developed citric acid (CA), dihydrolipoic acid (DHLA) and DHLA-Alanine (DHLA-Ala) directed rapid synthesis of ultra-stable AuNPs, DHLA@AuNPs and DHLA-Ala@AuNPs, under the UV (311 nm) irradiation at room temperature (RT: 25 °C) in around 10 min (min). CA is used as a potential reducing agent to expedite both reduction of Au3+ ion and AuNP formation, DHLA and DHLA-Ala act as stabilizing agents by replacing CA molecules on surface of AuNPs in order to produce quite stable AuNP. It is worthy to mention that reduction of Au3+ ion, formation and surface stabilization of AuNPs are consequently occurred in one step. We also investigated how experimental parameters including reaction time and temperature, pH of reaction solution, affect formation of the AuNPs. The effects of salt concentration and storage temperature were studied to show stability of the AuNPs. The synthesized DHLA@AuNPs and DHLA-Alanine@AuNPs were characterized via UV-Vis spectrophotometer (UV-Vis), scanning transmission electron microscope (STEM), dynamic light scattering (DLS) and Zeta potential (ZT) devices. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was efficiently catalyzed by the AuNPs in the presence of sodium borohydride in aqueous solution.

Immobilization of silver-loaded graphene oxide (Ag-GO) on canvas fabric support for catalytic conversion of 4 nitrophenol.

Due to the rising human population and industrialization, harmful chemical compounds such as 4-nitrophenol (4-NP) and various dyes are increasingly released into the environment, resulting in water pollution. It is essential to convert these harmful chemicals into harmless compounds to mitigate this pollution. This research focuses on synthesizing a novel heterogeneous catalyst using modified canvas fabric (CF) decorated with silver metal nanoparticles on graphene oxide nanosheets (Ag-GO/CF). The process involves coating the fabrics (CF) with graphene oxide (GO) nanosheets through sonication. Subsequently, silver nanoparticles are deposited in situ and reduced on the GO surface, resulting in the formation of the Ag-GO/CF composite. Various physicochemical characterizations were conducted to examine the interfacial interactions between CF, GO, and Ag nanoparticles. The catalytic activity of the nanocomposite was assessed by hydrogenating 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4). The results showed that the 10%Ag-5%GO/CF with a surface of 6 cm2 (3 × 2 cm) exhibited the highest catalytic activity, achieving a reduction efficiency of over 96% in 5 min. The 4-NP reduction reaction rate was well-fitted with a pseudo-first-order kinetics model with an apparent reaction rate constant (Kapp) of 0.676min-1. Furthermore, the Ag-GO/CF composite demonstrated remarkable stability over successive cycles, with no noticeable decrease in its catalytic activity, suggesting its promising application for long-term chemical catalytic processes. This synthesized composite can be easily added to and removed from the reaction solution while maintaining high catalytic performance in the reduction of 4-NP, and it could be beneficial in avoiding problems related to powder separation.

Cu-MOF-derived carbon nanomaterials as efficient catalysts for the reduction of nitro compounds

In this paper, we have synthesized a new light blue crystal Cu-MOF-1 with Cu(II) as the central metal ion by using two mixed ligands, where N,N’-bis(3-pyridyl)adipamide (3-bpaa) and fumaric acid (H2FA). Taking this material as the precursor of the study, it is found that Cu-MOF-1 possesses a single-crystal-to-single-crystal (SCSC) transition phenomenon, using its structure in the free state of water molecules in the heating process will be dehydrated and thus transformed into dark blue crystal Cu-MOF-2. This color distinctive change can be intuitively identify the temperature conversion, and thus be applied to the direction of the temperature sensing. Moreover, using Cu-MOF-1 as a precursor, the carbon-based nanostructured materials (Cu@X) of Cu and CuxO were derived from Cu-MOF-1 as a precursor in a straightforward and effective a single-step pyrolysis under different temperatures (400 °C, 600 °C, 800 °C and 1000 °C). As a result, Cu@1000 shown good activity (100 % conversion within 5 min) in the reduction of 4-nitrophenol (4-NP) by the presence of sodium borohydride (NaBH4) at mild circumstances, yielding a rate constant (Kapp) of 1.699 min−1. This remarkable performance is due to the utilization of both the uniform distribution of Cu-based nanoparticals (CuNPs) in the carbon matrix and the abundance of defect sites in the surface. This paper describes innovative MOF-derived catalysts that can be employed in a range of useful applications.

Exploring the versatility of carbohydrate-capped green silver nanoparticles as multi-dimensional reagents for targeted applications

The present work describes the impact of the structural diversity of different carbohydrate molecules on the morphology and sensing ability of silver nanoparticles synthesized by a green protocol using Ocimum sanctum leaf extract, used as the reducing agent. Seven different monosaccharides were utilized as capping and stabilizing agents during the green synthesis of silver nanoparticles. The carbohydrate-capped nanoparticles were more stable in solution than the uncapped counterpart for at least three months. The formation and stability of the silver nanoparticles were analyzed using UV-visible, fluorescence spectroscopy, and X-ray diffraction studies, whereas the morphological characteristics were studied using scanning electron microscopic analysis. The different types of interaction of sugar molecules with silver atoms were studied using DFT calculation. Silver nanoparticles synthesized using d-galactose and l-arabinose, having an axial-OH group at the C-4 position, were found to have the smallest size with maximum efficacy as chemosensors for toxic mercury (II) ions in aqueous medium. The green silver nanoparticles were successfully employed as antimicrobial agents against different gram-positive and gram-negative bacteria. The catalytic activity of silver nanoparticles in the degradation of organic dyes was also evaluated for Congo red, methyl orange and reactive blue in the presence of sodium borohydride. The nanoparticles showed excellent dye degradation activity with a minimum time duration.

Ag0, Re0, and Ag@Re heterogeneous persulfate activators for reactive radical based oxidation of water contaminant

Silver-rhenium bi-metallic nanoparticles (Ag-Re) were prepared by the combination of colloidal sols of silver and rhenium at room temperature. The silver and rhenium sols were synthesized by using the chemical reduction of silver nitrate and ammonium perrhenate with sodium borohydride in presence of cetyltrimethylammonium bromide (CTAB). The morphology (shape, size, elemental composition, oxidation states, and crystalline nature) and textural properties (pore size, pore volume, and surface area) of Ag0-Re0 were determined with EDX, SEM, TEM, XPS, XRD, and nitrogen adsorption-desorption isotherm. The Ag0-Re0 was used as heterogeneous persulfate (S2O82−) activator to generate reactive radical species (SO4−• and HO•) for the degradation of xylenol orange (XO) at 434 nm. The Ag-Re exhibits higher XO degradation efficiency than that of mono-metallic Ag0 and Re0 nanoparticles, respectively. The degradation efficiency strongly depends on the concentrations of S2O82−, XO, pH, temperature, and amount of Ag0-Re0. The role of SO4−• and HO• were established by using ethanol, and tertiary butanol as radical scavengers. The activation energy was found to be 85.2, 63.5, and 32.6 kJ/mol, respectively, to the degradation of XO by activated S2O82− with Re0, Ag0, and Ag0-Re0.

Bimetallic magnetic nanoparticles dispersed in glycerol: An efficient hydrophilic catalyst for the reduction of 4‐nitrophenol

A one‐pot, ecologically friendly method for the preparation of Fe/Ni, Fe/Co and Co/Ni bimetallic magnetic nanoparticles (MNPs) was reported, using glycerol as both a solvent and reducing agent. Six different bimetallic MNPs by varying the proportions of transition metals, namely, Fe, Co and Ni were synthesized by the chemical reduction method. The catalytic efficiency of the synthesized nanoparticles (NPs) was explored for the reduction of 4‐nitrophenol, and the reaction rate for different catalysts was systematically analysed. Especially, glycerol‐Fe/Co (1:3) bimetallic nanoparticles as a magnetically recoverable catalyst had higher catalytic activity than the other bimetallic nanoparticles for the reduction of 4‐nitrophenol to 4‐aminophenol in the presence of sodium borohydride. The reduction process was monitored by UV–visible spectroscopy, and the reaction was complete within 8 min. The kinetic study shows 99% conversion of 4‐nitrophenol to 4‐aminophenol, and the rate constant is 0.593 min−1. Furthermore, the glycerol‐Fe/Co (1:3) MNPs were retrieved from the reaction mixture and subsequently utilized in five consecutive cycles, demonstrating both the reusability and durability of the NPs as a catalyst. This research was remarkable for its fast reaction kinetics, simplified one‐pot conversion of 4‐nitrophenol to 4‐aminophenol without the need for mechanical or magnetic stirring and in‐depth study of six bimetallic MNPs' catalytic properties in nitro reduction. These findings explored the potential benefits of bimetallic magnetic NPs for the synthesis of 4‐aminophenol products.

Eco-Friendly biogenic synthesis, characterization of Au/Fe3O4 magnetic nanoparticles and its catalytic activity towards degradation of Rhodamine-B

Eco-Friendly biogenic synthesis of gold and iron oxide (Au/Fe3O4) Magnetic nanoparticles (MNPs) using Lepidagathis cristata (LC) leaf extract act as capping and reducing agent. The prepared MNPs was characterized by different analytical techniques such as UV-Vis, FT-IR, XRD, TEM, VSM and BET adsorption-desorption methods. The XRD revealed the formation of LC/Au/Fe3O4 MNPs with crystallite size of about~30 nm. The synthesized LC/Au/Fe3O4 MNPs were found to be ferromagnetic nature, which was confirmed by vibrating sample magnetometer (VSM) at room temperature. Besides, the prepared composite exhibits high specific surface area of 23.6 m2g-1. As well as, the LC/Au/Fe3O4 MNPs showed a good catalytic nature for the degradation of Rhodamine-B (Rh-B) in the presence of Sodium borohydride (NaBH4) in aqueous solution.

Rapid and sensitive aptamer-linked immunosorbent assay with aptamer-templated silver nanoparticles for detection of aflatoxin B1 in medicinal and edible food

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin commonly found in various medicinal and edible foods (MEFs). AFB1 in MEFs poses an inevitable threat to human health. High-performance analytical techniques are required for AFB1 detection in the quality assessment of MEFs. This work reports a novel aptamer-linked immunosorbent assay (ALISA) using aptamer-templated silver nanoparticles (AgNPs) as signal transducers for AFB1 detection. The effect of aptamer on the morphology and properties of AgNPs was systematically investigated. Aptamers with lower concentrations can induce the aggregation of AgNPs, thereby exhibiting excellent photothermal effects. Whereas, aptamers with higher concentrations mediate small-sized AgNPs' generation, demonstrating outstanding extinction coefficients. Accordingly, the effect of aptamer on the properties of AgNPs was used to construct a novel ALISA. Specifically, AFB1 aptamers were immobilized on 96-well plates via AFB1 and antibodies. In the presence of sodium borohydride (NaBH4) and silver nitrate (AgNO3), AgNPs were synthesized in a one-pot manner using the free aptamer as a template. The concentration of free aptamer can regulate AgNP morphology, affecting extinction coefficient and photothermal effect, enabling visual colorimetric and portable photothermal signal readout. When employed for AFB1 detection in MEFs, the proposed ALISA demonstrated rapid detection speed and high sensitivity, with a response time of 8 min and a colorimetric signal detection limit of 0.33 pg/mL. We expect that this ALISA not only enables rapid and cost-effective AFB1 detection but also offers a universal, user-friendly, and highly sensitive method for detecting other MEF hazards.

PH-dependent catalytic activity of Au and Pd-based hybrid cryogels by investigating the acid/base nature of the polymeric phase

Over the last decade, cryogels have proven to be effective catalytic supports in various hybrid systems for the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-NP). A critical determinant influencing the conversion of nitroaromatic compounds in the presence of sodium borohydride is the solution pH as suggested from Grzeschik's model. This study aims to investigate the catalytic mechanism and the role of pH in reactions mediated by hybrid catalysts. In particular, polymeric cryogels with different acid/base properties were prepared and used as supports for the in-situ preparation of Au and Pd nanocatalysts. Notably, catalytic tests showed the significant influence of the polymeric support's acidity on 4-NP reduction, with poly(acrylic acid)-based catalysts emerging as the most effective systems. To further probe the reaction mechanism, a series of catalytic tests were carried out, and the results demonstrated the effect of pH on the reaction process, allowing to propose a novel mechanism based on an extension of Grzeschik's model. Moreover, data emphasized the pivotal role of the polymer in the catalytic mechanism, showcasing its capacity to tune catalytic activity by altering the acid/base properties of the matrix substrates.

Preparation of Flower-like Nanosilver Based on Bioderived Caffeic Acid for Raman Enhancement and Dye Degradation.

In this study, a simple, green, and low-cost room temperature synthesis of broccoli-like silver nanoflowers (AgNF) with a particle size of about 300-500 nm was developed using plant-derived caffeic acid as a reducing agent and polyvinylpyrrolidone as a dispersant under ultrasound assistance. The flower clusters covered by small nanocrystals of 20-50 nm significantly enhance the electromagnetic field signals. AgNF was deposited on the surface of silicon wafers as a surface-enhanced Raman spectroscopy sensor for the detection of probe molecules such as rhodamine 6G (R6G) and malachite green with high sensitivity, homogeneity, and reproducibility. AgNF was deposited on cotton fabrics in the form of composites to catalyze the degradation of dye pollutants such as R6G, MG, and methyl orange in the presence of sodium borohydride. 0.1 g of AgNF/cotton fabric could assist 15 mmol/L NaBH4 to achieve over 90% degradation of various dyes as well as a high concentration of dyes in 12 min with good reusability and recyclability. The AgNF synthesized in this work can not only monitor the type and amounts of pollutants (dyes) in wastewater but also catalyze the rapid degradation of dyes, which is expected to be valuable for industrial applications.

Polymerized stimuli-responsive microgel hybrids of silver nanoparticles as efficient reusable catalyst for reduction reaction

We have showcased the potential of polymerized hydrogels (PGMs) with uniform-sized stimuli-responsive microgel particles as promising alternatives to prevent aggregation in solution based nanoparticle systems. In the current work, we implemented the PGM concept by embedding anionic stimuli-responsive microgels (PNIPAM-co-AAc)-silver (Ag) hybrids within a hydrogel matrix. These PGM@AgNP hybrid materials are used as catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride. UV-VIS spectroscopy is used for studying catalytic activity. In the solution based system, the complete reduction of 4-NP to 4-AP took 30 minutes with pure Ag nanoparticles, 24 minutes with PNIPAM-Ag hybrid (Neutral) microgels and 15 minutes with PNIPAM-co-AAc-Ag (Anionic) hybrid microgels. In contrast PGM containing PNIPAM-co-AAc-Ag hybrids achieved full reduction in just 15 minutes, along with a 3-minute induction period. For pure Ag nanoparticles, the first-order rate constant is found to be 0.25 min−1, for PNIPAM-Ag hybrid (Neutral), it is 0.21 min−1 and for PNIPAM-co-AAc-Ag (Anionic), it is 0.5 min−1 where as for PGM containing anionic microgel hybrids it is found to be 0.8 min−1. Furthermore, the reusability of the PGM-Ag (anionic) materials for catalytic activity remains unaltered even after several washings. In summary, our study highlights the effectiveness of PGM@AgNP materials as efficient catalysts for the reduction of 4-nitrophenol to 4-aminophenol, indicating their versatile potential in various catalytic applications.

CO2-Driven N-Formylation/N-Methylation of Amines Using C-Scorpionate Metal Complexes.

C-scorpionate metal complexes, specifically, [NiCl2(tpm)]·3H2O, [CoCl2(tpm)]·3H2O and [PdCl2(tpm)] [tpm = hydrotris(1H-pyrazol-1-yl)methane], were effective in the N-formylation and N-methylation of amines using carbon dioxide, as carbon source, in the presence of sodium borohydride. Various parameters were studied, including reaction time, temperature, solvent volume, presence of additives, and catalyst amount. These parameters were found to have a significant impact on the selectivity of the product. [NiCl2(tpm)]·3H2O exhibited good conversion at 80 °C, but its selectivity towards formamide decreased with prolonged reaction time. Increasing the amount of [NiCl2(tpm)]·3H2O, the selectivity changed. [PdCl2(tpm)] showed different selectivity compared to [NiCl2(tpm)]·3H2O, while [CoCl2(tpm)]·3H2O presented poor results. Monitoring the reaction course by 1H NMR revealed the presence of an intermediate species that influenced product formation. These results highlight the versatility and catalytic potential of C-scorpionate metal complexes in the N-formylation/N-methylation of amines in the catalytic system (NaBH4/MeCN/CO2).

Ruthenium complexes with triazenide ligands bearing an N-heterocyclic moiety, and their catalytic properties in the reduction of nitroarenes.

A series of ruthenium complexes of formulae [RuCl(triazenide)(p-cymene)] have been synthesized using as ligand a triazenide monofunctionalized with an N-heterocyclic moiety. Nuclear magnetic resonance, high resolution mass spectrometry and X-ray diffraction were used to characterize the triazenide ligands and their complexes. In addition, these ruthenium complexes catalyzed the reduction of nitrobenzene to aniline in the presence of sodium borohydride and ethanol as solvent at room temperature. Notably, complex 5 was especially active in the reduction of nitroarenes substituted at the aromatic ring with electron-withdrawing or electron-donating fuctional groups affording the desired arylamines in good to excellent yields (80-100%). The role of the N-heterocyclic moiety on catalysis was explored.

Synthesis and characterization of chitosan-copper nanocomposites and their catalytic properties for 4-nitrophenol reduction

Biopolymer-based copper nanoparticles (CuNPs) have become an area of significant interest due to their wide-ranging applications in a variety of fields. However, there remains a challenge in tailoring their morphologies and improving their properties. In this study, CuNPs were synthesized via wet chemical reduction using sodium hypophosphite monohydrate (NaH2PO2·H2O), l-ascorbic acid and chitosan. The effect of different synthesis conditions, including reaction pH, temperature, time, concentration of NaH2PO2·H2O, l-ascorbic acid and chitosan, as well as the deacetylation degree (DD) of chitosan, on the synthesis of CuNPs was investigated. The synthesized CuNPs were characterized by various analytical techniques. The catalytic properties of synthesized CuNPs were investigated for the reduction of 4-nitrophenol (4-NP) in the presence of sodium borohydride. The synthesis-morphology-catalytic activity relationship of CuNPs was discussed. The results suggested that the morphology of CuNPs could be adjusted by controlling the synthesis conditions. Chitosan DD significantly impacts the morphology of the synthesized CuNPs. As the chitosan DD decreased from 91.8 % to 52.3 %, the average particle size of synthesized CuNPs decreased from 43.9 ± 10.6 to 17.7 ± 5.9 nm and the shape changed from anisotropy to near-sphere. CuNPs synthesized using low DD (53.2 %) chitosan (CuNPs-N3) demonstrated the highest 4-NP conversion rate of 99.1 % and reaction rate constant of 0.3540 min−1. CuNPs-N3 was thermodynamically and kinetically more feasible than CuNPs synthesized with high DD chitosan. These findings provide important insights for further designing and developing hierarchical nanostructured CuNPs catalysts for broader applications.

Use of NIR/NaBH4 combinatorial techniques for simultaneous and high-efficient adsorption of heavy metal ions from contaminated water by Chitosan/Au Janus microdisks

This article discusses the creation of a disk-shaped microsorbent with Janus morphology made with chitosan and coated with gold on one side using the sputtering technique. The aim of the research is to explore how sodium borohydride and near-infrared (NIR) light can enhance the adsorption of heavy metal ions by our synthesized adsorbent. The changes in surface morphology and composition of the chitosan part of Janus microdisks, after acid treatment and crosslinking reaction, before and after adsorption process were investigated through scanning electron microscopy (SEM). The chitosan/Au Janus microdisks were utilized in auto-catalyzed adsorption of heavy metals including, Pb, Cu, Cd, Zn, and Ni, in the presence of sodium borohydride. The isotherm, kinetic, and thermodynamic curves of adsorbance in the presence of metals were investigated. In addition, the performance of Janus microsorbents in the co-existing ions solution was studied under different conditions. The synthesized microsorbents can remove Cu ions selectively from contaminated water (>99 %) with the help of sodium borohydride. In addition, the NIR light irradiation exhibited a synergistic effect on the adsorption of Cd, Ni, and Pb ions in the presence of sodium borohydride. The borohydride ions can change the surface charge of microdisks after adsorption on their surface and increase the adsorption rate of metal cations. In addition, NIR light irradiation can accelerate the reaction of sodium borohydride with metal ions.

Synthesis and characterization of hybrid nanocatalyst (AgNPs-Fe2O3) for catalytic remediation of hazardous 2,4-dinitrophenol

Hybridized nanocatalysts (AgNPs-Fe2O3) were prepared with silver nitrate and ferric chloride in the presence of sodium borohydride. The synthesized nanocatalyst was calcined, milled, and sieved for further applications. The nanocatalyst was characterized using Fourier transform infrared spectroscopy (FTIR) for the identification of functional moieties involved in the synthesis of the nanocatalyst. The vibrations of Fe and Ag were found at 566, 790 and 892 cm-1. The crystalline nature of the nanocatalyst was determined using X-ray diffraction (XRD) studies. The diffraction peaks for Ag and Fe can be seen at 2θ values of 30.42, 44.36, 62.45, 42.24 and 53.25. The morphology and elemental analysis of nanocatalysts were studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX). The particles are found to be spherical in shape. The signal for Ag and Fe can be found at 3.0 keV and 0.7, 6.3, 7.0 keV, respectively. The synthesized nanocatalyst was employed in the remediation of 2,4-dinitrophenol. The AgNPs-Fe2O3 nanocatalyst completely reduced (97%) the 2,4-dinitrophenol to 2,4-diaminophenol within 24 h.
 KEY WORDS: Nanocatalyst, Chemical precipitation, Impregnation methodology, Milling, Sieving, Remediation
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 113-121. DOI: https://dx.doi.org/10.4314/bcse.v38i1.9

Palladium nanoparticles on polydimethylsiloxane film for C−C coupling reactions, and catalytic reduction of organic pollutants in water

AbstractIn this study, we present a novel method for immobilizing Palladium nanoparticles (Pd NPs) onto a polydimethylsiloxane (PDMS) support (Pd NPs@PDMS). To enhance the stability of Pd NPs on the PDMS surface, we functionalized a PDMS thin film with amine groups. The structure and morphology of the resulting Pd NPs@PDMS material were characterized using various techniques, including field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X‐ray photoelectron spectroscopy (XPS) measurements. Furthermore, we investigated the catalytic performance of the Pd NPs@PDMS nanocatalyst for the reduction of well‐known environmental pollutants, such as 4‐nitrophenol (4‐NP), 2‐nitrophenol (2‐NP), 4‐nitroaniline (4‐NA), Methyl Orange (MO), Methylene Blue (MB), and Congo Red (CR), in the presence of sodium borohydride (NaBH4) at room temperature (RT). Additionally, we explored the application of the prepared nanocatalyst in carbon‐carbon (C−C) coupling reactions, specifically Suzuki Miyaura and Sonogashira reactions. The results obtained in this study demonstrated the high efficiency and environmentally friendly nature of Pd NPs@PDMS as a catalyst for both C−C coupling reactions and the degradation of organic pollutants.

Effects of silver nanoparticles prepared by aqueous extract of Ferula communis on the developing mouse embryo after maternal exposure.

Green synthesis of silver nanoparticles (AgNPs) from aqueous silver nitrate has been achieved using an extract of Ferula communis leaf as a capping, reducing, and stabilizing agent. The formation and stability of the green synthesized silver nanoparticles in the colloidal solution were monitored by absorption measurements. Silver nanoparticles were characterized by different analyses such as X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and FT-IR spectroscopy. The average particle size of silver nanoparticles was determined by high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) analyses. In this experiment, pregnant female mice were divided into four groups (G); G1 was the control and received phosphate-buffered saline, G2 received orally aqueous extract of F. communis leaf, G3 received orally AgNPs chemically prepared by NaBH4, and G4 received orally AgNPs prepared by aqueous extract of F. communis leaf. The diameter of AgNPs was 20nm. AgNPs exhibited good catalytic reduction ability toward methyl orange in the presence of sodium borohydride with a rate constant of 2.95 x 10-4 s-1. The results revealed the occurrence of resorbed embryos in G2, G3, and G4 with different percentages. The livers of mothers and embryos at E14.5 in G2, G3, and G4 showed different levels of histopathological alteration and increase in GFAP and CTGF expressions compared with the control group. The study concluded that the oral administration of small-sized AgNPs (20nm) prepared by Ferula extract had less toxicity than those prepared by the chemical method.