Catalytic Reduction Of 4-nitrophenol Research Articles

Catalytic Reduction of 4-Nitrophenol and Methylene Blue with Silver Nanoparticles Decorated with Drymoglossum piloselloides Extract

Drymoglossum piloselloides is one of the epiphytic plants that is commonly found in Southeast Asia region. In this study, the ethanol extract of D. piloselloides plant has been used in the green synthesis of silver nanoparticles. The synthesized silver nanoparticles were characterized by ultraviolet-visible (UV-Vis) spectrophotometry, X-ray diffraction (XRD),Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM) measurements. The UV-Vis spectrum of silver nanoparticles showed a maximum wavelength at 453 nm. The XRD measurement showed the silver nanoparticles peaks at 38.38°, 44.60°, 64.76°, and 77.62°. The FTIR spectra provided evidence of the interaction between silver and chemicals in the plant extract as a weak signal at 682 cm-1. Meanwhile, TEM revealed an average size of 12.63nm. The synthesised silver nanoparticles were utilised for the reduction of 4-nitrophenol with a conversion percentage of up to 100% with a reduction reaction rate constant of 7.104 s-1. In addition, methylene blue was also successfully reduced with the synthesised silver nanoparticles as the catalyst with a reduction reaction rate constant (k) of 21.150 s-1. This study highlights the superior advantage of utilizing ethanolic extract of D. piloselloides to prepare silver nanoparticles with promising catalytic reduction purposes.

Metal-organic frameworks (MOFs) wrapped palladium nanoparticles-loaded Fe3O4@CFR core-shell magnetic nanohybrid as heterogeneous catalyst with robust catalytic properties

Metal-organic frameworks (MOFs) wrapped palladium nanoparticles supported on Fe3O4@catechol formaldehyde resin (Fe3O4@CFR@Pd@MOF) as magnetic nanohybrid catalyst was successfully fabricated by employing the redox capacity of CFR shell of Fe3O4@CFR core-shell microsphere for in situ formation of Pd NPs, followed by surface coating with Cu-MOF(HKUST-1). The research results demonstrated that the complementary properties of the various components within this hybrid material yielded magnetic recyclable nanocatalysts with exceptional catalytic performance. The Fe3O4@CFR@Pd@MOF catalyst exhibited remarkable advantages in the catalytic reduction of nitrophenol, demonstrating a transformation frequency (TOF) value of up to 4651 h−1. Additionally, the nanocatalyst was proved to have robust catalytic capacity in the reduction of organic dyes and Suzuki-Miyaura reaction. The HKUST-1 framework played a triple role: facilitating dye enrichment, Cu2+ assisting Pd NPs catalysis, and mitigating Pd NPs leaching. Moreover, the synthesized catalyst exhibited favorable magnetic properties, enabling facile separation by magnets for efficient recycling and reutilization.

Carbonized cellulose microspheres loaded with Pd NPs as catalyst in p-nitrophenol reduction and Suzuki-Miyaura coupling reaction

Catalytic reduction of p-nitrophenol is usually carried out using transition metal nanoparticles such as gold, palladium, silver and copper, especially palladium nanoparticles, which are characterized by fast reaction rate, high turnover frequency, good selectivity and high yield. However, the aggregation and precipitation of the metals lead to the decomposition of the catalyst, which results in a significant reduction of the catalytic activity. Therefore, the preparation of homogeneous stabilized palladium nanoparticle catalysts has been widely studied. Stabilized palladium nanoparticles mainly use synthetic polymers. Cellulose microspheres, as a natural polymer material with low cost and porous fiber network structure, are excellent carriers for stabilizing metal nanoparticles. Cellulose microspheres impregnated with palladium metal nanoparticles were carbonized to have a larger specific surface area and highly dispersed palladium nanoparticles, which exhibited excellent catalytic activity in the catalytic reduction of 4-nitrophenol. In this aspect, cellulose carbon-based microspheres Pd nanoparticles (Pd@CCM) catalysts were designed and characterized by SEM, TEM, EDS, XRD, FTIR, XPS, TGA, BET and so on. Furthermore, the catalytic performance of Pd@CCM catalysts were investigated via 4-nitrophenol reduction, which showed high catalytic activity. This catalyst also exhibited excellent catalytic performance in Suzuki-Miyaura coupling reaction. Linking aromatic monomer and benzene through Suzuki-Miyaura coupling was presented as an effective route to obtain polymeric substrate with low-cost and simple synthesis method. In addition, cellulose carbon-based microspheres Pd nanoparticles catalyst showed desirable recyclability with maintaining its catalytic activity even after five recycles. This work is highly suggestive on the heterogeneous catalysts design and application.

Biosynthesis of CuFe2O4@Ag hybrid nanocomposite: Ultrasensitive detection and catalytic reduction of 4-nitrophenol

Due to the dearth of extremely capable, sensitive, and stable catalysts, the efficient detection and catalytic removal of 4-nitrophenol (4-NP) in industrial wastewater remains a serious challenge. The detection and determination of 4-nitrophenol (4-NP) presence in the environment is a matter of paramount importance because it is a high-priority hazardous pollutant that can affect people, animals, and plants. Here, we present a promising and economically viable green synthetic route for fabricating CuFe2O4 and CuFe2O4@Ag hybrid nanocomposites from the leaf extract of Senna didymobotrya. The UV–Vis, FTIR, XRD, FE-SEM, EDXA, BET and VSM analysis were performed to characterize the synthesis of CuFe2O4@Ag nanocomposite. To evaluate the electrocatalytic capacity of CuFe2O4@Ag, electrochemical sensing stratergy was performed with cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The modified CuFe2O4@Ag glassy carbon electrode (GCE) (CuFe2O4@Ag/GCE) demonstrated a linear response in the range of 0.01-15 μg/ml (71 nm-107 μM) and the ability to detect 4-NP at low concentration (0.006 μg/ml (43 nM)). Due to the increased surface area of CuFe2O4@Ag/GCE by ̴ 1.5-fold, a greater cathodic current response (-16 μA/cm2) at a low potential of -0.81 V was observed compared to CuFe2O4/GCE alone for the detection of 4-NP. Additonally, CuFe2O4@Ag showed excellent reduction ability towards 4-NP using NaBH4 with an efficiency of 96.4 % which was higher than the CuFe2O4 (only 87.3 %) in 12 min due to the synergistic relationship among Ag NPs and CuFe2O4 nanostructures. The outcomes from this study shows that the bi-functional electrocatalyst holds vast potential for environmental remediation.

Surface Deposition of Magnesium Ferrite-Based Supports with Bimetallic Gold/Silver Nanoparticles for the Catalytic Reduction of Nitroaromatics.

Surface deposition of magnesium ferrite nanoparticles (MgFe2O4 NPs) with bimetallic gold/silver (Au/Ag) nanoparticles was conducted using the seed-mediated growth method to obtain magnetic-metallic composite catalysts for use in the catalytic reduction of nitroaromatics. Two types of amine-functionalized MgFe2O4 and MgFe2O4@SiO2 NPs were used as magnetic supports for the surface deposition process. The combination of several characterization analyses (i.e., XRD, XPS, TEM, SEM, EDS, and VSM) confirmed the successful syntheses of the MgFe2O4/Au/Ag and MgFe2O4@SiO2/Au/Ag NPs. The catalytic reduction of 4-nitrophenol using sodium borohydride as a reducing agent revealed that the reaction was completed within 2 min by using MgFe2O4/Au/Ag and MgFe2O4@SiO2/Au/Ag NPs as catalysts. The appearance rate constant of the MgFe2O4/Au/Ag NPs was slightly higher than that of the MgFe2O4@SiO2/Au/Ag NPs. In terms of reusability, high conversion (>80%) of the reduction of 4-nitrophenol was still obtained after 7 and 10 consecutive cycles for the MgFe2O4/Au/Ag and MgFe2O4@SiO2/Au/Ag catalysts, respectively. Interestingly, these two catalysts exhibited the highly catalytic conversion of the chosen nitroaromatic derivatives (i.e., 4-nitrobenzaldehyde and 4-nitroaniline). On the whole, the MgFe2O4/Au/Ag and MgFe2O4@SiO2/Au/Ag NPs could be utilized as suitable and sustainable catalysts for the catalytic reduction of nitroaromatics due to several desirable features (i.e., high activity, facile and rapid separation by a magnet, and good reusability).

Crystal plane effect of copper with different oxides/hydroxides nano-composites on catalytic performance and mechanism towards the reduction of 4-nitrophenol

Here, four copper oxide/hydroxide composites Cu/CuO, Cu-Cu2O/Fe2O3, Cu-CuO/Co(OH)2, and Co(OH)2/CuO with CuO(111) or Cu(111) as the central exposed crystal plane were synthesized and used in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). A study of the dynamic changes of reaction was carried out by real-time HPLC-Q-Orbitrap-HRMS/MS, HPLC, UV–Vis detection, and DFT simulation. It revealed that in copper based catalytic reduction of 4-NP, three different reaction mechanisms are generated over four catalysts. The different adsorption modes and higher adsorption strength of 4-NP on the CuO(111) and Cu(111) plane make it selective and active for both direct hydrogenation and condensation in the reduction of 4-NP. The synergistic effect of different metal crystal faces with CuO(111) can improve the catalytic activity, especially the CuO(111)/Co(OH)(011) crystal planes that have the best synergistic effect on the reduction of 4-NP. This work reports an example where the reaction mechanism was significantly affected by the principal exposed crystal planes of copper oxide/hydroxide composites. It can be very informative for understanding the catalytic processes and providing new ideas for the design of novel catalysts.

A comprehensive review on biogenic synthesis of bimetallic nanoparticles and their application as catalytic reduction of 4-nitrophenol

A comprehensive review on biogenic synthesis of bimetallic nanoparticles and their application as catalytic reduction of 4-nitrophenol

Efficient Removal and Recovery of Ag from Wastewater Using Charged Polystyrene-Polydopamine Nanocoatings and Their Sustainable Catalytic Application in 4-Nitrophenol Reduction.

This study addresses the long-standing challenges of removing and recovering trace silver (Ag) ions from wastewater while promoting their sustainable catalysis utilization. We innovatively developed a composite material by combining charged sulfonated polystyrene (PS) with a PDA coating. This composite serves a dual purpose: effectively removing and recovering trace Ag+ from wastewater and enabling reused Ag for sustainable applications, particularly in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The PS-PDA demonstrated exceptional selectivity to trace Ag+ recycling, which is equal to 14 times greater than the commercial ion exchanger. We emphasize the distinct roles of different charged functional groups in Ag+ removal and catalytic reduction performance. The negatively charged SO3H groups exhibited the remarkable ability to rapidly enrich trace Ag ions from wastewater, with a capacity 2-3 times higher than that of positively-N+(CH3)3Cl and netural-CH2Cl-modified composites; this resulted in an impressive 96% conversion of 4-NP to 4-AP within just 25 min. The fixed-bed application further confirmed the effective treatment capacity of approximately 4400 L of water per kilogram of adsorbent, while maintaining an extremely low effluent Ag+ concentration of less than 0.1 mg/L. XPS investigations provided valuable insights into the conversion of Ag+ ions into metallic Ag through the enticement of negatively charged SO3H groups and the in situ reduction facilitated by PDA. This breakthrough not only facilitates the efficient extraction of Ag from wastewater but also paves the way for its environmentally responsible utilization in catalytic reactions.

Plant axillary stem gall extract mediated bioengineered CuO nanoprisms as robust and reusable catalyst for photocatalytic and catalytic degradation of water pollutants

The current work explains the synthesis of bioengineered CuO nanoprisms using axillary stem gall extract of the Ziziphus mauritiana plant. The photocatalytic and catalytic reduction potential of bioengineered CuO nanoprisms was analyzed for the photo-mineralization of methylene blue (MB) organic dye under exposure to visible light and catalytic reduction of 4-nitrophenol (4-NP) in the presence of NaBH4 solution. The biogenic CuO nanoprisms were characterized using XRD, FTIR, FESEM, EDS, and UV–Vis. spectroscopic techniques. The mean crystallite size of CuO nanoprisms was estimated to be 34.24 nm while the band gap energy value was found to be 1.47 eV. 99.21 % of MB dye was photo-mineralized within 70 min of visible light illumination at pH=5 and 30 mg of catalyst whereas 4-NP was almost completely reduced to 4-AP within 5 min in the presence of bioengineered CuO (NPs). The data of photo-mineralization of MB dye and catalytic reduction of 4-NP well agreed to the pseudo-first-order kinetics with the rate constant values of 63.86 × 10−3 and 0.8439 min−1, respectively. The reactive species entrapping studies revealed that •OH radicals were the key active species affianced in the photo-mineralization of MB dye. Photostability and reusability tests established that only a 9 % decline in the dye degradation efficiency of bioengineered CuO was observed after the fifth cycle of reuse under visible light irradiation.

Synergistic effect of copper and nickel oxides from MOF-74 precursors for enhanced catalytic reduction of p-nitrophenol

Catalytic reduction stands out as a promising approach for wastewater treatment due to its inherent simplicity, mild reaction conditions, and high efficiency. In this work, Cu/Ni-MOF-74 precursors with different Cu2+/Ni2+ ratios were prepared by hydrothermal method and calcined them at 400 °C for 2 h to obtain the corresponding CuO/NiO composite catalysts. The experimental results showed that the catalytic reduction of 4-Nitrophenol (4-NP) by CuO/NiO was significantly stronger than that of CuO and NiO separately. Remarkably, the best CuO/NiO-1 catalytic reduction of 4-NP exhibits the pseudo-first-order kinetic constant k of 0.28 min−1 and the mass normalization constant km of 56 min−1 mg−1. Compared with CuO and NiO, the prepared CuO/NiO-1 composite catalyst with a large specific surface area can provide more active sites for the adsorption and diffusion of 4-NP. Notably, this catalytic reaction mechanism aligned with the Langmuir-Hinshelwood model. Theoretical investigations further elucidated that the synergistic interplay between CuO and NiO bolstered the adsorption of H species and 4-NP, while also aiding in product desorption. This study not only presents a novel approach for designing and synthesizing highly active catalysts for 4-NP but also lays the groundwork for future advancements in this field.

FeCx-coated biochar nanosheets as efficient bifunctional catalyst for electrochemical detection and reduction of 4-nitrophenol

Herein, we present the exceptional performance of FeCx-coated carbon sheets (FC) derived from the pyrolysis of waste biomass as a bifunctional catalyst for electrochemical detection and catalytic reduction of 4-nitrophenol (4-NP). Despite having a lower surface area, larger particle size, and lesser N content, the FC material prepared at a calcination temperature of 900 °C (FC900) outperforms the other samples. Deeper investigations revealed that the FC900 efficiently facilitates the charge transfer process and enhances the diffusion rate of 4-NP, leading to increased surface coverage of 4-NP on the surface of FC900. Additionally, relatively weaker interactions between 4-NP and FC900 allow the facile adsorption and desorption of reaction intermediates. Due to the synergetic interplay of these factors, FC900 exhibited a linear response to changes in 4-NP concentration from 1 μM to 100 μM with a low limit of detection (LOD) of 84 nM (S/N = 3) and high sensitivity of 12.15 μA μM−1 cm−2. Importantly, it selectively detects 4-NP in the presence of five times more concentrated 2-aminophenol, 4-aminophenol, catechol, resorcinol, and hydroquinone and ten times more concentrated metal salts such as Na2SO4. NaNO3, KCl, CuCl2, and CaCl2. Moreover, FC900 can accurately detect micromolar levels of 4-NP in river water with high recovery values (99.8–103.5 %). In addition, FC900 exhibited outstanding catalytic activity in reducing 4-NP to 4-aminophenol (4-AP), achieving complete conversion within 8 min with a high-rate constant of 0.42 min−1. FC900 also shows high recyclability in six consecutive catalytic reactions due to Fe magnetic property.

Facile green synthesis of Phyllanthus emblica extract based Ag-NPs for antimicrobial and response surface methodology based catalytic reduction applications

Silver nanostructures were synthesized by utilizing facile and simple green methodology based on the usage of biogenic Phyllanthus emblica fruit extract. The Fourier transform infrared spectroscopy revealed that the numerous phytochemicals were found to be present in the extract that were responsible for reducing the precursor salt into nanoparticles. After 10 min, the silver nanoparticles were formed in the system while the further nucleation for 30 min resulted in the generation of the silver nanostructures with dual morphology (spherical & rod-like morphology). The reaction time/nucleation time was found to be the major factor responsible for the modulation of the morphology of the biogenic nanomaterials. The crystalline nature with the cubic crystal system was observed in the case of the silver nanostructure via X-ray diffraction analysis. The antimicrobial efficacy investigated for these nanostructures revealed that the silver nanostructures possess comparable or greater efficacy than the selected control. The excellent efficacy is attributed to the smaller size and the peculiar morphological characteristics of the silver nanostructures. The catalytic reduction of 4-nitrophenol via silver nanostructures was also investigated by using the response surface methodology as an optimization tool. An extremely high percentage reduction value of 96.491 % with the rate constant value of 0.277 min−1 was documented in the case of Ag-NSs. The prepared silver nanostructures were found to be extremely stable till six reuse cycles. Our findings affirm that the efficient synthesis of nanostructures is achieved by using P. emblica fruit extract and the synthesized material further presents excellent viability for antimicrobial and catalytic applications.

Novel, Biosynthesis of Palladium Nanoparticles using Strychnos Potatorum Polysaccharide as a Green sustainable approach; and their effective Catalytic Hydrogenation of 4-Nitrophenol

In the current study, we successfully used strychnos potatorum polysaccharide through autoclaving to synthesize palladium nanoparticles in a green, sustainable process. These polysaccharide act as a stabilizing, capping, and reducing agent. It also used various analytical characterizations, including UV–Visible spectroscopy, FT-IR spectroscopy, X-Ray diffraction (XRD), Scanning electron microscopy (FE-SEM), EDAX, and X-ray photoelectron spectroscopy (XPS), TEM and gel permeation chromatography (GPC) are used to analyze biosynthesized pallidum nanoparticles (PdNPs). The surface plasmon resonance (SPR) band at 276 nm and UV–visible spectroscopy revealed the presence of the generated PdNPs. The XRD data show that PdNPs have crystalline behavior and a pristine face-centered cubic (FCC) structure. The PdNPs were successfully developed by catalytic reduction of 4-nitrophenol (4-NP). The catalytic activity and reusability of the environmentally friendly PdNPs catalyst were demonstrated by achieving a remarkable transformation of 95 % nitrophenol to 4-aminophenol after five cycles. The reaction rate constant (k) for the degradation of 4-nitrophenol (4-NP) using SP-PdNPs as a catalyst is 0.1201 min−1 and R2 0.9867, with a normalized rate constant of (Knor = K/m) of 7.206 s−1 mM−1. These findings provide fundamental knowledge of the catalytic process governing the hydrogenation of p-nitrophenol, which will help designers of effective catalysts. An innovative and affordable technique for creating PdNPs that are environmentally acceptable and can be utilized as effective catalysts in environmental applications is the use of strychnos potatorum gum polysaccharide. The green-synthesized PdNPs can be used for pollutant remediation, including pharmaceutical, domestic, heavy metal, industrial, and pesticide pollutants.

Green synthesis of Multifunctional Zinc oxide Nanoparticles from Cordia myxa gum; and their Catalytic Reduction of Nitrophenol, Anticancer and Antimicrobial Activity

In situ exfoliated natural polysaccharide Cordia myxa (CMX) is used to promote the utilization of zinc-oxide nanoparticles for eco-friendly catalytic hydrogenation of p-nitrophenol (p-NP) and microbial growth inhibition. Polysaccharide-mediated biosynthetic nanocomposite materials are interesting because they are cheap, green, and environmentally friendly. This study uses CMX gum as a bioreduction to produce multifunctional, environmentally friendly zinc-oxide nanocomposites (ZnO NPs). The process involves a low reaction time and temperature and utilizes CMX as a reducing and stabilizing agent. The structural, morphological, and optical properties of the CMX-ZnO nanocomposite were characterized. The biosynthetic CMX-ZnO NPs exhibited robust catalytic activity and recycling capacity for rapidly oxidizing hazardous p-NPs. The complete reduction of 4-NP to CMX-ZnO NPs in excess NaBH4 was achieved within 15 min, with recyclability and pseudo-first-order kinetics with a rate constant of 0.2571 min−1. Additionally, human colon cancer (HCT116) and 3T3L1 cell lines were remarkably sensitive to the cytotoxic effects of ZnO nanoparticles. CMX-ZnO NPs exhibited potent antibacterial properties against human pathogenic gram-positive and gram-negative bacteria (Bacillus, Salmonella, E. coli, and Pseudomonas aeruginosa) based on the zone of inhibition measured by the disc-diffusion method. The significant antibacterial activity of CMX-ZnO NPs can overcome the current limitations associated with removing water-soluble organic pollutants and microbiological contaminants for long-term environmental sustainability.

Fabrication of graphene nanoplatelets/MgAl-layered double hydroxide nanocomposites as efficient support for gold nanoparticles and their catalytic performance in 4-nitrophenol reduction

The catalytic reduction of 4-nitrophenol is of considerable importance to a multitude of applications and industries. The present work introduces a new catalyst (AuNP/GNP/MgAl-LDH) containing gold nanoparticles (AuNP) supported on graphene nanoplatelets (GNP) intercalated in Mg Al layered double hydroxides (MgAl-LDH) for the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a reducing agent. The catalyst was characterised by FTIR, XRD, STEM, TEM, and BET specific surface area. The XRD analysis showed the presence of crystalline phases of gold on the supports, while TEM demonstrated that MgAl-LDH provided uniform binding sites for AuNPs and prevented agglomeration. Similar reaction rate constant was determined for the disappearance of 4-nitrophenol and for the appearance of 4-aminophenol. The reaction rate constant was the highest for AuNP/GNP/MgAl-LDH, followed by AuNP/MgAl-LDH and AuNP/GNP. AuNP/GNP/MgAl-LDH was found stable after five repeated cycles.

Controlled Shell and Kernel Modifications of Atomically Precise Pd/Ag Superatomic Nanoclusters.

The first 8-electron Pd/Ag superatomic alloys with an interstitial hydride [PdHAg19(dtp)12] (dtp = S2P(O i Pr)2-) 1 and [PdHAg20(dtp)12]+2 are reported. The targeted addition of a single Ag atom to 1 is achieved by the reaction of one equivalent of trifluoroacetic acid, resulting in the formation of 2 in 55% yield. Further modification of the shell results in the formation of [PdAg21(dtp)12]+3 via an internal redox reaction, with the system retaining an 8-electron superatomic configuration. The interstitial hydride in 1 and 2, contributes its 1s1 electron to the superatomic electron count, and occupies a PdAg3 tetrahedron. The distributions of isomers corresponding to different dispositions of the outer capping Ag atoms are investigated by multinuclear VT-NMR spectroscopy. The emissive state of 3 has a lifetime of 200 μs (λex =448; λem =842), while 1 and 2 are non-emissive. The catalytic reduction of 4-nitrophenol is demonstrated with 1-3 at room temperature.

Binuclear Mn(III) and Fe(III) porphyrin nanostructured materials in catalytic reduction of 4-nitrophenol

Biomimetic reduction reactions may disclose alternatives to the use of noble metals or transition metals of late series that are expensive, toxic, or scarcer. In this work, binary nanostructured materials carrying positive and negative iron (III) and manganese (III) porphyrins were prepared by ionic self-assembly, in a simple and eco-sustainable way, and characterized by SEM, XRD, UV–vis and XPS. The materials were evaluated as catalysts in the reduction of 4-nitrophenol in water, using NaBH4 as a reductant. The effect of the crystallite structures, of the nature of the dual metal ion centers and of solar light, in the catalyst activity were also evaluated. The highest activity was observed for a heterobimetallic [Mn/Fe] material carrying Fe(III) and Mn(III) porphyrins as positive and negative tectons, respectively, leading to complete conversion of the 4-nitrophenol in 3 min under simulated solar light, and the results evidence a synergy between the two metal centers. This material was reused in successive catalytic cycles until the 7th cycle.

Dual role of flower-like Fe3O4/Ag microstructure in electrocatalytic detection and catalytic reduction of 4-nitrophenol

In this work, a novel Ag-incorporated 3D flower-like porous Fe3O4 magnetic microstructure (Fe3O4/Ag-FM) was effectively prepared via a quasi-reverse emulsion soft template approach and reductive deposition of Ag nanoparticles. The synthesized Fe3O4/Ag-FM material was applied for the electrochemical sensing and catalytic reduction of 4-nitrophenol (4-NP). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used to determine the electrochemical sensing ability of the synthesized material. Results showed that the fabricated Fe3O4/Ag-FM-based electrode detected a low concentration of 4-NP (0.093 μM) and a linear response in the range of 1.0–15 μM. Furthermore, the Fe3O4/Ag-FM material also exhibited excellent reduction ability towards 4-NP with the assistance of NaBH4. This is because a synergistic effect formed between Ag nanoparticles and flower-like Fe3O4 magnetic microstructure enhanced the catalytic activity towards electrochemical detection and reduction of 4-NP. Overall, the current strategy could help design and synthesize future catalysts that can work as sensors and catalysts.

Prolonged colloidal stability of silver nanoparticles through Mentha spicata leaf extract as reducing agent, and their catalytic reduction of 4-nitrophenol

Prolonged colloidal stability of silver nanoparticles through Mentha spicata leaf extract as reducing agent, and their catalytic reduction of 4-nitrophenol

SnLa2O5 wrapped carboxymethyl cellulose mixed calcium alginate nanocomposite beads for efficient reduction of pollutants

In this project, lanthanum oxide doped tin oxide (SnLa2O5) nanomaterial was prepared and characterized morphologically and physiochemically by different techniques. The catalytic performance of SnLa2O5 was assessed toward catalytic reduction of 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), methylene blue (MB) and potassium ferricyanide (K3[Fe(CN)6]). SnLa2O5 was found to be efficient for K3[Fe(CN)6] in the presence of NaBH4, which reduced in only 8.0 min. SnLa2O5 was further wrapped in carboxymethyl cellulose mixed calcium alginate (CMC-Alg) hydrogel beads because the powder catalyst cannot be simply recovered from reaction media to recycle and use again. SnLa2O5 wrapped CMC-Alg (SnLa2O5/CMC-Alg) was assessed for detail analysis of K3[Fe(CN)6] reduction. The effect of NaBH4, K3[Fe(CN)6] concentration and amount of catalyst was optimized using SnLa2O5/CMC-Alg. The amount of catalyst has positive impact on catalytic reduction of K3[Fe(CN)6]. The kinetic study revealed that K3[Fe(CN)6] reduction by SnLa2O5 and SnLa2O5/CMC-Alg was fast, which completed in 8.0 and 4.0 min with rate constant of 0.4283 min−1 and 0.7461 min−1, respectively. These findings indicated that the developed SnLa2O5/CMC-Alg is best and proficient nanocatalyst for K3[Fe(CN)6] reduction. The efficiency along with cost-effective and simple treatment route of the developed nanocatalyst have prospect to compete and replace the reputable commercial catalysts.