Rapid Catalytic Reduction of 4-Nitrophenol and Clock Reaction of Methylene Blue using Copper Nanowires

Multiplicative rGO/Cu-BDC MOF for 4-nitrophenol reduction and supercapacitor applications

Two-dimensional nanosheets, with their distinct characteristics, are widely used in various applications such as water splitting, supercapacitors, catalysis etc. In this research, we produced Cu-BDC MOF nanosheets by using Cu2O nanotubes for metal ions and H2BDC as the organic linker. We combined these Cu-BDC MOF nanosheets with reduced graphene oxide (rGO) to form a nanocomposite. The collaboration between Cu-BDC MOF and rGO boosts both the catalytic reduction of 4-nitrophenol and the electrochemical capabilities. The conversion of 4-nitrophenol to 4-aminophenol is achieved using sodium borohydride as both a reducing agent and a catalyst. The study explores the impact of different concentrations of 4-nitrophenol and sodium borohydride on catalytic efficiency. The increase in sodium borohydride concentration enhances catalytic efficiency by providing more BH4- ions and electrons for the reduction process. The catalytic reduction process adheres to the Langmuir-Hinshelwood mechanism with apparent pseudo-first-order kinetics. Specifically, Cu-BDC MOF and rGO/Cu-BDC MOF exhibit specific capacities of 468.4 mA h/g and 656.4 mA h/g at a current density of 2 A/g, respectively, while also enhancing the operating voltage window. Therefore, electrodes based on rGO/Cu-BDC MOF nanosheets present a novel approach for environmental remediation and energy storage applications across various fields.

Composite Track-Etched Membranes: Synthesis and Multifaced Applications

Composite track-etched membranes (CTeMs) emerged as a versatile and high-performance class of materials, combining the precise pore structures of traditional track-etched membranes (TeMs) with the enhanced functionalities of integrated nanomaterials. This review provides a comprehensive overview of the synthesis, functionalization, and applications of CTeMs. By incorporating functional phases such as metal nanoparticles and conductive nanostructures, CTeMs exhibit improved performance in various domains. In environmental remediation, CTeMs effectively capture and decompose pollutants, offering both separation and detoxification. In sensor technology, they have the potential to provide high sensitivity and selectivity, essential for accurate detection in medical and environmental applications. For energy storage, CTeMs may be promising in enhancing ion transport, flexibility, and mechanical stability, addressing key issues in battery and supercapacitor performance. Biomedical applications may benefit from the versality of CTeMs, potentially supporting advanced drug delivery systems and tissue engineering scaffolds. Despite their numerous advantages, challenges remain in the fabrication and scalability of CTeMs, requiring sophisticated techniques and meticulous optimization. Future research directions include the development of cost-effective production methods and the exploration of new materials to further enhance the capabilities of CTeMs. This review underscores the transformative potential of CTeMs across various applications and highlights the need for continued innovation to fully realize their benefits.

Efficient Reduction in Methylene Blue Using Palladium Nanoparticles Supported by Melamine-Based Polymer

In this work, palladium nanoparticles, supported by polyaminals (Pd@PAN-NA), were synthesized via a reverse double solvent approach and used as a nano catalyst. The thermogravimetric and the elemental analysis revealed that the catalyst had good dispersity and improved thermal stability. The catalytic activity of the prepared Pd@PAN-NA catalyst was studied for a methylene blue chemical reaction in the presence of NaBH4 as a reducing agent. The effect of the catalyst dose, pH, and dye initial concentration were examined to optimize the chemical reduction conditions. The prepared catalyst Pd@PAN-NA removed 99.8% of methylene blue organic dye, indicating its potential effect for treating waste and contaminated water.

In-situ preparation of sulfonated carbonaceous copper oxide-zirconia nanocomposite as a novel and recyclable solid acid catalyst for reduction of 4-nitrophenol

The missing-linker defects of UiO-66 were exploited to covalently anchor Cu nanoclusters (Cu/UiO-66). The molecular interactions between the metals and oxides as copper-zirconia interfaces in Cu/UiO-66 are essential for heterogeneous catalysis, leading to remarkable synergistic impacts on activity and selectivity. Homogeneously distributed carbonaceous mixed metal oxides (CuO/ZrO₂@C) nanocomposite was prepared via carbonization of the Cu/UiO-66 at 600 °C for 3 h in air. To enhance the acidity properties of the CuO/ZrO₂@C nanocomposite, a small amount of sulfuric acid was added and heated at 150 °C under an N₂ atmosphere (CuO/ZrO₂-SO₃H@C). The synthesised Cu/UiO-66 and CuO/ZrO₂-SO₃H@C catalysts were used as novel catalysts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The Cu/UiO-66 and CuO/ZrO₂-SO₃H@C catalysts displayed complete conversion of the 4-NP solution during (4 and 2 min) stirring at room temperature, respectively. These two catalysts exhibited a high reduction rate of 8.61 × 10^-3 s^-1, and 18.3 × 10^-3 s^-1, respectively. The X-ray photoelectron spectroscopic (XPS) analysis showed the charge of copper atoms in the Cu/UiO-66 catalyst was Cu⁰/Cu^II and in the CuO/ZrO₂-SO₃H@C catalyst was Cu^I/Cu^II with nearly the same ratio (65/35). The particle size and the elemental composition of the CuO/ZrO₂-SO₃H@C catalyst were analysed by using high resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy (EDS), and elemental mapping, respectively. The key point beyond the high catalytic activity and selectivity of the CuO/ZrO₂-SO₃H@C catalyst is both the carbon-metal oxides heterojunction structure that leads to good dispersion of the CuO and ZrO₂ over the carbon sheets, and the high acidity properties that come from the combination between the Brønsted acid sites from sulfuric acid and Lewis acid sites from the UiO-66. The catalysts exhibited good recyclability efficiency without significant loss in activity, indicating their good potential for industrial applications.

Remarkably and stable catalytic activity in reduction of 4-nitrophenol by sodium sesquicarbonate-supporting Fe2O3@Pt

Reasonable design of bimetallic nanomaterials with support is beneficial to improve catalytic performance. This work reports a new kind of sodium sesquicarbonate-supporting Fe₂O₃@Pt via etching Fe₃O₄@Pt@SiO₂, which exhibits highly efficient and stable catalytic reduction performance towards 4-NP. Sodium sesquicarbonate-supporting Fe₂O₃@Pt has an interconnected one-dimensional network structure that provides sufficient channels for mass transfer. At the same time, a large amount of Fe₂O₃@Pt is exposed on its surface, which hinders the aggregation of pt clusters and Fe₂O₃ nanoparticles, and facilitates the direct contact of Fe₂O₃@Pt reaction sites with reactant molecules, thus improving the catalytic rate of 4-NP reduction reaction. Moreover, the introduction of non-metallic Fe can not only reduce the consumption of precious metal Pt, but also improve the catalytic efficiency due to the synergistic effect. This study opens up a new avenue to develop robust catalysts for heterogeneous catalytic reactions.

Eco-friendly PVA-LYS fibers for gold nanoparticle recovery from water and their catalytic performance

In this work, we grafted lysine on PVA electrospun fibers, using a green preparation technique. The resulting fiber mats were proposed for gold nanoparticles (AuNPs) removal from water. The efficiency of three fibers with different lysine amounts (10, 20, and 30%) was investigated. The incorporation of amino groups in PVA fibers was firstly proved by FTIR, SEM, and elemental analysis, confirming the presence of lysine. Among the three different fibers, PVA-LYS 30% has shown the best removal efficiency, reaching 65%, at pH equal to 5. Adsorption isotherms were studied and showed that the Langmuir model is the best model fitting our experimental results, with a maximum adsorption capacity of 20.1 mg g^-1. Metal-ligand interactions and electrostatic attraction between protonated amino groups of lysine on the fibers and negatively charged, citrate capped, AuNPs are the main proposed mechanisms for AuNP adsorption on the fibers. Sustainability of AuNPs adsorbed on these fibers has been checked through their reuse as catalyst for the reduction of 4-nitrophenol to 4-aminophenol. The process was completed within 60 min, and their reusability showed more than 99% efficiency after 5 reduction cycles. Our results prove that green PVA-LYS fibers can extract nanoparticles from water, as low cost-effective and eco-friendly adsorbent, and contribute to the promotion of a circular economy approach, through their reuse as catalyst in the reduction of pollutants.

Synthesis of p-Aminophenol from p-Nitrophenol Using CuO-Nanoleaf/g-Al2O3 Catalyst

The CuO-nanoleaf/g-Al2O3 catalyst was synthesized through wet chemical impregnation and had promising catalytic activity in reducing p-Nitrophenol (PNP) into p-Aminophenol (PAP). The synthesis was conducted in situ with Ethylene Glycol as a stabilizer agent of the CuO-nanoleaf structure and g-Al2O3 as catalyst support with high adsorption ability. Furthermore, the crystal phase, morphology, element composition, and specific surface area were investigated by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and N2 adsorption-desorption, respectively. The XRD pattern showed the crystal phase of CuO and g-Al2O3 in the composite, and the morphology was successfully reported using FESEM. The increase in the specific surface area of the catalyst indicates that the CuO material was well composited in g-Al2O3. The catalyst has good activity in reducing PNP to PAP with 93.53% PNP conversion within 4 min. In addition, the reduction reaction of PNP with excess NaBH4 could be categorized as pseudo-first order kinetic with a constant rate of 0.6935 min−1 for CuO-nanoleaf/g-Al2O3 catalyst. The loading catalyst and temperature reaction effect on PNP conversion were also investigated. The results showed that 94.18% PNP conversion was obtained within only 2.5 min under the optimized conditions. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synthesis of poly (N-isopropyl acrylamide-co-2-acrylamido methylpropane sulfonic acid) hydrogel containing copper and nickel nanoparticles with easy recycling and efficient catalytic potential

Poly(N-isopropyl acrylamide-co-2-acrylamido methyl propane sulfonic acid) hydrogel was prepared and used as matrix for the fabrication of nickel and copper nanoparticles. Nickel and copper nanoparticles were fabricated via in situ reduction of Ni (II) and Cu (II) ions within the hydrogel matrix. The manufactured hydrogel and its corresponding composites with Ni and Cu nanoparticles were characterized by FTIR, XRD, EDX, TEM, and TGA. Thermal stability of hydrogel was found to be increased upon fabricating with metal nanoparticles. The hydrogel showed ability to absorb water 63 times of its weight in dried form. The Ni and Cu nanoparticles were observed to be well dispersed, spherical in shape and most of them were having diameters in the range of 12.5 to 38.8 nm and 58 to 102 nm, respectively. The as-prepared hydrogel-nickel and hydrogel-Cu nanocomposite were used as catalysts for the reduction of a toxic pollutant 4-nitrophenol. At 25 °C, the reduction of 4-NP was found to proceed with apparent rate constant (k app) of 0.107 and 0.122 min−1 in the presence of composite containing Ni and Cu nanoparticles, respectively. However, k app was increased with corresponding increase in temperature and its maximum value was found to be 0.815 min−1 at 88 °C with catalyst containing Ni nanoparticles. The formation of well dispersed Ni and Cu nanoparticles in the prepared hydrogel reflected that this hydrogel system can act as efficient stabilizing agent along with acting as a reactor medium. Recycling potential of catalysts was studied for five successive cycles.

Chitosan-Grafted Polyacrylic Acid-Doped Copper Oxide Nanoflakes Used as a Potential Dye Degrader and Antibacterial Agent: In Silico Molecular Docking Analysis

This study examined the catalytic and bactericidal properties of polymer-doped copper oxide (CuO). For this purpose, a facile co-precipitation method was used to synthesize CuO nanostructures doped with CS-g-PAA. Various concentrations (2, 4, and 6%) of dopants were systematically incorporated into a fixed amount of CuO. The prepared samples were analyzed by different optical, structural, and morphological characterizations. Field emission scanning electron microscopy and transmission electron microscopy micrographs indicated that doping transformed CuO's agglomerated rod-like surface morphology to form nanoflakes. UV-vis spectroscopy revealed that the optical spectra of the samples exhibit a redshift after doping, leading to a decrease in band gap energy from 3.3 to 2.5 eV. The purpose of the study was to test the catalytic activity of pristine and CS-g-PAA doped CuO for the degradation of methylene blue in acidic, basic, and neutral conditions using NaBH4 as a reducing agent in an aqueous medium. Furthermore, antibacterial activity was evaluated against Gram-positive and Gram-negative bacteria, namely, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Overall, enhanced bactericidal performance was observed upon doping CS-g-PAA into CuO, i.e., 4.25-6.15 and 4.40-8.15 mm against S. aureus and 1.35-4.20 and 2.25-5.25 mm against E. coli at the lowest and highest doses, respectively. The relevant catalytic and bactericidal action mechanisms of samples are also proposed in the study. Moreover, in silico molecular docking studies illustrated the role of these prepared nanomaterials as possible inhibitors of FabH and FabI enzymes of the fatty acid biosynthetic pathway.

A novel nanocomposite (g-C3N4/Fe3O4@P2W15V3) with dual function in organic dyes degradation and cysteine sensing

Among the important needs of human societies is the elimination of environmental pollution and also the construction of high-performance and inexpensive biosensors. In this regard, the construction of multi-functional composites has been considered. A novel magnetic graphite carbon nitride decorated by tri-vanadium substituted Dawson-type heteropolytungstate nanocomposite (C₃N₄/Fe₃O₄@P₂W₁₅V₃) effectively synthesized and characterized by prevalent functional analysis. The prepared nano-catalyst presents bi-functional usage involving photocatalytic removal of dyes (methylene blue, congo red and phenyl red) (around 98%) under visible light radiation and greatly sensitive colorimetric sensing of cysteine in an aqueous media. Moreover, synthesized nano-catalyst successfully recovered five times without any considerable deficiency on its photocatalytic ability. Further, Moreover, we propose a novel method for cysteine detection based on the C₃N₄/Fe₃O₄@P₂W₁₅V₃ nanocomposite. This nanocomposite displayed a privileged catalytic feature for cysteine oxidation to extend a clock reaction of methylene blue as an indicator in the presence of NaBH₄ in acidic solution. More importantly, this colorimetric sensing method of cysteine presents an easy, low-cost, selective, and rapid colorimetric assay with a detection limit value of 7.2 μM in the acceptable linear range of 5-600 μM.

Alginate biopolymer as a reactor container for copper oxide-tin oxide: Efficient nanocatalyst for reduction of different pollutants

The need of clean water demands to design an efficient catalytic system with high effective and selective reduction of water pollutants. Here, we successfully prepared copper oxide-tin oxide (CuO-SnO₂) nanomaterial and further wrapped in Na-alginate hydrogel (Alg/CuO-SnO₂). CuO-SnO₂ and Alg/CuO-SnO₂ were characterized by FESEM, EDS, FTIR-ATR, and XRD and tested for the reduction of water pollutants. The catalytic ability of CuO-SnO₂ and Alg/CuO-SnO₂ was examined for numerous pollutants like 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), methylene blue (MB) and potassium ferricyanide (K₃[Fe(CN)₆]) where the designed CuO-SnO₂ and Alg/CuO-SnO₂ nanocatalysts were most selective toward MB reduction. Further on optimization of catalyst amount, stability, and reducing agent amount, it was found that the increase of nanocatalyst amount and NaBH₄ concentration increase the rate of MB reduction. CuO-SnO₂ and Alg/CuO-SnO₂ nanocatalysts reduced MB in 3.0 min with reaction rate constants (k_app) of 1.2944 min^-1 and 1.2715 min^-1, respectively. Additionally, Alg/CuO-SnO₂ nanocatalyst was easily recovered by simply pulling hydrogel after completion of reaction and reused four times with no loss in efficiency. Besides, Alg/CuO-SnO₂ nanocatalyst was further investigated in real samples like sea water, irrigation water, well water, university wastewater and found effective for MB reduction even in real samples.

Concurrent Oxidation-Reduction Reactions in a Single System Using a Low-Plasma Phenomenon: Excellent Catalytic Performance and Stability in the Hydrogenation Reaction

The catalytic activity and stability of metal nanocatalysts toward agglomeration and detachment during their preparation on a support surface are major challenges in practical applications. Herein, we report a novel, one-step, synchronized electro-oxidation-reduction "bottom-up" approach for the preparation of small and highly stable Cu nanoparticles (NPs) supported on a porous inorganic (TiO₂@SiO₂) coating with significant catalytic activity and stability. This unique embedded structure restrains the sintering of CuNPs on a porous TiO₂@SiO₂ surface at a high temperature and exhibits a high reduction ratio (100% in 60 s) and no decay in activity even after 30 cycles (>98% conversion in 3 min). This occurs in a model reaction of 4-nitrophenol (4-NP) hydrogenation, far exceeding the performance of most common catalysts observed to date. More importantly, nitroarene, ketone/aldehydes, and organic dyes were reduced to the corresponding compounds with 100% conversion. Density functional theory (DFT) calculations of experimental model systems with six Cu, two Fe, and four Ag clusters anchored on the TiO₂ surface were conducted to verify the experimental observations. The experimental results and DFT calculations revealed that CuNPs not only favor the adsorption on the TiO₂ surface over those of Fe and AgNPs but also boost the adsorption energy and activity of 4-NP. This strategy has also been extended to the preparation of other single-atom catalysts (e.g., FeNPs-TiO₂@SiO₂ and AgNPs-TiO₂@SiO₂), which exhibit excellent catalytic performance.

The Photochemical Chlorate-Iodide Clock Reaction

Mixing iodide and perchloric acid solutions with an excess of chlorate inside a diode-array spectrophotometer led to the observation of an abrupt decrease of the absorbance at the 215 nm isosbestic point after an induction period. The clock time decreases by increasing the initial concentrations of chlorate and acid, but increasing the initial iodide concentration has an opposite effect. The proposed mechanism simulates the experimental results and considers the interaction of UV light with iodide, producing iodine and triiodide ion. The autocatalytic core of this mechanism is the same as that employed to explain the autocatalytic behavior of chlorine dioxide-iodine reaction, but considering H₂IO⁺ as the reactive species rather than HOI, being a more realistic mechanism for acid conditions.

Nanoflakes-like nickel cobaltite as active electrode material for 4-nitrophenol reduction and supercapacitor applications

Catalytic reduction of nitroaromatic compounds present in wastewater by nanostructured materials is a promising process for wastewater treatment. A multifunctional electrode based on ternary spinal nickel cobalt oxide is used in the catalytic reduction of a nitroaromatic compound and supercapacitor application. In this study, we designed nanoflakes- like nickel cobaltite (NiCo₂O₄) using a simple, chemical, cost-effective hydrothermal method. Nanoflakes- like NiCo₂O₄ samples are tested as catalysts toward rapid reduction of 4-nitrophenol and as electrode materials for supercapacitors. The conversion of 4-nitrophenol into 4-aminophenol is achieved using a reducing agents like sodium borohydride and NiCo₂O₄ catalyst. Effect of catalyst loading, 4-nitrophenol and sodium borohydride concentrations on the catalytic performance of 4-nitrophenol is studied. As sodium borohydride concentration increases the catalytic efficiency of 4-nitrophenol increased due to more BH₄^- ions available which provides more electrons for catalytic reduction of 4-nitrophenol. Catalytic reduction of 4-nitrophenol using sodium borohydride as a reducing agent was based on the Langmuir-Hinshelwood mechanism. This mechanism follows the apparent pseudo first order reaction kinetics. Additionally, NiCo₂O₄ electrode is used for energy storage application. The nanoflakes-like NiCo₂O₄ electrode deposited at 120 °C shows a higher specific capacitance than samples synthesized at 100 and 140 °C. The maximum specific capacitance observed for NiCo₂O₄ electrode is 1505 Fg^-1 at a scan rate of 5 mV s^-1 with high stability of 95% for 5000 CV cycles.

Continuous Synthesis of Uniformly Dispersed Mesoporous SBA-15 Supported Silver Nanoparticles in a Coiled Flow Inverter Reactor

Mesoporous silica supported nanocatalysts have shown great potential in industrial processes due to their unique properties, such as high surface area, large pore volume, good chemomechanical stability and so on. Controllable and tunable synthesis of supported nanocatalysts is a crucial problem. Continuous synthesis of supported nanoparticles has been reported to get uniformly dispersed nanomaterials. Here, a method for continuous synthesis of uniformly dispersed mesoporous SBA-15 supported silver nanoparticles in a coiled flow inverter (CFI) microreactor is described. Compared to Ag/SBA-15 synthesized in the conventional batch reactor and Ag synthesized in continuous flow, mesoporous silica nanocatalysts synthesized in continuous flow are found to have smaller average size (7-11 nm) and narrower size distribution. The addition of capping agents can effectively change the characteristic of catalysts. Moreover, two kinds of support with different surface area and pore size have been added into the continuous synthesis. This method can provide further understandings for the synthesis of uniformly dispersed supported nanocatalysts in continuous flow, especially for mesoporous nanomaterials, which provides the possibilities of large-scale yield process of supported nanocatalysts in industry.

Radiation-induced synthesis of copper sulfide nanotubes with improved catalytic and antibacterial activities

In the current paper, copper sulfide nanotubes have been successfully synthesized via the green, simple, and effective gamma-radiolysis method without adding any capping or reducing agents. The structural and morphological characteristics of the as-prepared CuS nanotubes were investigated by X-ray diffraction (XRD), N₂ adsorption-desorption measurements at 77 K, transmission electron microscopy (TEM), and ultraviolet-visible (UV-vis) spectroscopy, which all demonstrated the formation of pure CuS covellite phase with tubular morphology. The synthesized CuS nanotubes possessed not only high activity towards the reduction of both cationic (methylene blue) and anionic (Congo red) dyes in the presence of NaBH₄ but also exhibited excellent reusability. In addition, the pseudo-first-order kinetic model represented the reduction of MB very well, and the value of the normalized rate constant (2.4 × 10^-2 s^-1 mg^-1) was higher than those of other solid catalysts reported in the literature. Ultimately, CuS nanotubes were found to have a broad-spectrum microbicidal action against the common microbiota, such as Gram-positive (exemplified by Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (exemplified by Pseudomonas aeruginosa and Escherichia coli), yeast (exemplified by Candida albicans), and plant pathogenic fungi (exemplified by Aspergillus niger).

Recent Advancement of Emerging Nano Copper-Based Printable Flexible Hybrid Electronics

Printed copper materials have been attracting significant attention prominently due to their electric, mechanical, and thermal properties. The emerging copper-based flexible electronics and energy-critical applications rely on the control of electric conductivity, current-carrying capacity, and reliability of copper nanostructures and their printable ink materials. In this review, we describe the growth of copper nanostructures as the building blocks for printable ink materials on which a variety of conductive features can be additively manufactured to achieve high electric conductivity and stability. Accordingly, the copper-based flexible hybrid electronics and energy-critical devices printed by different printing techniques are reviewed for emerging applications.

Completely green synthesis of rose-shaped Au nanostructures and their catalytic applications

A novel protocol for the one-pot, template/seed-free, and completely green synthesis of rose-shaped Au nanostructures with unique three-dimensional hierarchical structures was developed.

Copper Nanowires as Highly Efficient and Recyclable Catalyst for Rapid Hydrogen Generation from Hydrolysis of Sodium Borohydride

Hydrogen (H₂) is a clean energy carrier which can help to solve environmental issues with the depletion of fossil fuels. Sodium borohydride (NaBH₄) is a promising candidate material for solid state hydrogen storage due to its huge hydrogen storage capacity and nontoxicity. However, the hydrolysis of NaBH₄ usually requires expensive noble metal catalysts for a high H₂ generation rate (HGR). Here, we synthesized high-aspect ratio copper nanowires (CuNWs) using a hydrothermal method and used them as the catalyst for the hydrolysis of NaBH₄ to produce H₂. The catalytic H₂ generation demonstrated that 0.1 ng of CuNWs could achieve the highest volume of H₂ gas in 240 min. The as-prepared CuNWs exhibited remarkable catalytic performance: the HGR of this study (2.7 × 10¹⁰ mL min⁻¹ g⁻¹) is ~3.27 × 10⁷ times higher than a previous study on a Cu-based catalyst. Furthermore, a low activation energy (E_a) of 42.48 kJ mol⁻¹ was calculated. Next, the retreated CuNWs showed an outstanding and stable performance for five consecutive cycles. Moreover, consistent catalytic activity was observed when the same CuNWs strip was used for four consecutive weeks. Based on the results obtained, we have shown that CuNWs can be a plausible candidate for the replacement of a costly catalyst for H₂ generation.

Synthesis of AgNPs coated with secondary metabolites of Acacia nilotica: An efficient antimicrobial and detoxification agent for environmental toxic organic pollutants

This study concentrates on biosynthesis of Silver Nanoparticles (AgNPs) from stem extract of Acacia nilotica (A. nilotica). The reaction was completed at a temperature ~40-45 °C and time duration of 5 h. AgNPs were thoroughly investigated via advanced characterization techniques such as UV-Vis spectrophotometry (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffractometry (XRD), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X-ray Photoelectron Spectroscopy (XPS), Thermo Gravimetric Analysis (TGA), Diffuse Reflectance Spectroscopy (DRS), Brunner-Emmett-Teller (BET), Dynamic Light Scattering (DLS), and Zeta potential analysis. AgNPs with average size below 50 nm were revealed by all the measuring techniques. Maximum surface area ~5.69 m²/g was reported for the as synthesized NPs with total pore volume ~0.0191 mL/g and average pore size ~1.13 nm. Physical properties such as size and shape have changed the surface plasmon resonance peak in UV-visible spectrum. Antimicrobial activity was reported due to denaturation of microbial ribosome's sulphur and phosphorus bond by silver ions against bacterium Methicillin Resistant Staphylococcus aureus (MRSA) and fungus Candida Albican (CA). Furthermore, AgNPs degraded toxic pollutants such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP) and various hazardous dyes such as Congo Red (CR), Methylene Blue (MB) and Methyl Orange (MO) up to 95%. The present work provided low cost, green and an effective way for synthesis of AgNPs which were utilized as potential antimicrobial agents as well as effective catalyst for detoxification of various pollutants and dyes.

The composition dependent structure and catalytic activity of nanostructured Cu–Ni bimetallic oxides

Nanostructured CuO–NiO bimetallic oxide was used as a catalyst for the effective conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).

Simultaneous degradation and reduction of multiple organic compounds by poly(vinyl imidazole) cryogel-templated Co, Ni, and Cu metal nanoparticles

Simultaneous degradation of methylene blue, eosin Y and 4-nitrophenol reduction by p(vinyl imidazole)–Co cryogel composite catalyst in aqueous environments.