Catalytic Reduction Of 4-nitroaniline Research Articles

1,4-α-Glucosidase from Fusarium solani for Controllable Biosynthesis of Silver Nanoparticles and Their Multifunctional Applications.

In the study, monodispersed silver nanoparticles (AgNPs) with an average diameter of 9.57 nm were efficiently and controllably biosynthesized by a reductase from Fusarium solani DO7 only in the presence of β-NADPH and polyvinyl pyrrolidone (PVP). The reductase responsible for AgNP formation in F. solani DO7 was further confirmed as 1,4-α-glucosidase. Meanwhile, based on the debate on the antibacterial mechanism of AgNPs, this study elucidated in further depth that antibacterial action of AgNPs was achieved by absorbing to the cell membrane and destabilizing the membrane, leading to cell death. Moreover, AgNPs could accelerate the catalytic reaction of 4-nitroaniline, and 86.9% of 4-nitroaniline was converted to p-phenylene diamine in only 20 min by AgNPs of controllable size and morphology. Our study highlights a simple, green, and cost-effective process for biosynthesizing AgNPs with uniform sizes and excellent antibacterial activity and catalytic reduction of 4-nitroaniline.

Stabilization of silver nanoparticles in crosslinked polymer colloids through chelation for catalytic degradation of p-nitroaniline in aqueous medium

Poly (N-isopropylacrylamide-2-hydroxy ethyl methacrylate-acrylic acid) [P(NHA)] colloidal particles of core-shell morphology were obtained by free radical emulsion polymerization. Loading of Silver nanoparticles within P(NHA) colloidal particles was attained by in-situ reduction. P(NHA) and Ag-P(NHA) particles were characterized by UV–Vis and TEM. For probing catalytic ability of Ag-P(NHA) hybrid particles, catalytic reduction of 4-Nitroaniline (4-NA) was carried out as an exemplary reaction. Ag-P(NHA) hybrid particles served as an exceptional nano-catalyst for reduction of 4-NA. Comparison of current study with academic literature proves that our system provides rapid and simple approach for efficient and cost-effective reduction of 4-NA in aqueous condition.

Synthesis of gold nanoflowers assisted by a CH-CF hybrid surfactant and their applications in SERS and catalytic reduction of 4-nitroaniline

In this paper, an effective approach was successfully developed to synthesize gold nanoflowers (GNFs) using a hydrocarbon/fluorocarbon (CH-CF) hybrid surfactant (1). Upon mixing with aqueous solution of 1 in presense of AgNO3, HAuCl4 could be reduced into GNFs by ascorbic acid (AA). Influences of aging time, concentration of HAuCl4, AgNO3, AA and 1 as well as temperature were investigated in detail. GNFs could not be obtained at the absence of AgNO3 and 1, indicating that both of them play important roles in the formation of these anisotropic gold structures. Influences of AA and temperature are relatively less pronounced, and well-defined GNFs can be synthesized in a wide range of the concentration of AA (1×10−3 mol·L−1 to 6×10−3 mol·L−1) and temperature (25–50°C). The GNFs have inhomogenous cores, indicating that they are formed by the aggregation of gold crystals of smaller sizes. A two-stage growth pathway was thus proposed to explain the mechanism of the formation of GNFs. With a large surface-to-volume ratio, GNFs show surface-enhanced Raman scattering for solid R6G with enhancement factors up to a magnitude of 106. They can also be used as efficient catalysts for the reduction of 4-nitroaniline by KBH4. The strategy demonstrated here is a facile, rapid, and contrallable one-pot method for the synthesis of GNFs in aqueous solution, which will bring out a wide range of applications.

Polyelectrolyte assisted synthesis and enhanced catalysis of silver nanoparticles: Electrocatalytic reduction of hydrogen peroxide and catalytic reduction of 4-nitroaniline

A facile method was developed for the one-step synthesis of silver nanoparticles (AgNPs), co-stabilized by the polyelectrolyte poly(acrylamide-co-diallyldimethylammoniumchloride) (PADA) and the silicate matrix N1-(3-trimethoxysilylpropyl)diethylenetriamine (TPDT). Here, TPDT acted as reducing agent and both PADA and TPDT served as capping agent for AgNPs. As PADA improved the catalytic properties of AgNPs, its concentration was optimized and the optimum concentration of PADA was found to be 1wt.% among the concentrations 0.25, 0.5, 1 and 2wt.%. The AgNPs were characterized using UV–vis absorption spectroscopy, HRTEM, EDX, SAED and FTIR analyses. The PADA(1)-Ag-TPDT NPs showed the better catalytic activity towards electrochemical reduction of H2O2 and catalytic conversion of 4-nitroaniline (4-NA) to p-phenylenediamine (PPD). The PADA(1)-Ag-TPDT NPs was used to construct the non-enzymatic electrochemical sensor for the detection of H2O2. Using the linear sweep voltammetry (LSV) and square wave voltammetry (SWV) techniques, the lowest experimental detection limits attained for H2O2 sensing were 5 and 0.2μM, respectively. Moreover, remarkably a fast conversion of 4-NA to PPD was observed over the PADA(1)-Ag-TPDT NPs catalyst with a rate constant of 0.096s−1 and the product (PPD) formation was confirmed by 1H NMR spectroscopy.

Biogenic Synthesis of Silver Nanoparticles Using Cnidium officinale Extract and Their Catalytic Reduction of 4-Nitroaniline

Silver nanoparticles (AgNPs) with two different morphologies were synthesized using aqueous extract of Cnidium officinale rhizomes under different reaction conditions and applied to the facile aqueous phase reduction of 4-nitroaniline (4-NA) as catalysts. The synthesized AgNPs are characterized by UV–Visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) method and high resolution transmission electron microscopy (HR-TEM) with energy dispersive X-ray spectroscopy (EDS) analysis. HR-TEM showed that the synthesized AgNPs had two different morphological forms; truncated triangular prism shapes with a mean size of ~35 nm and spherical shapes with a mean size of ~9 nm. The HR-TEM and XRD results are consistent with the standard values. The catalytic activities of both AgNPs were compared on the reduction of 4-NA in water by NaBH4 as a reducing agent. The reduction of 4-NA was monitored using UV–Visible spectroscopy. The ~9 nm (spherical) sized AgNPs showed superior catalytic activity than the larger AgNPs. The calculated rate constant (k) for the catalytic reduction of 4-nitroanilie by spherical AgNPs was 11.16 × 10−3 s−1.

Flowerlike Bi2S3microspheres: facile synthesis and application in the catalytic reduction of 4-nitroaniline

Flowerlike Bi2S3 microspheres have been successfully synthesized via a facile wet chemical route in air at 110 °C for 10 min, employing bismuth nitrate and thiourea in a molar ratio of 1 : 2 as the starting reactants, ethylene glycol as the reaction medium and polyvinylpyrrolidone (PVP) as the structure-directing reagent. Electron microscopy observations showed that the as-obtained product looked like an Asteraceae plant called Echinops Sphaerocephalus Linn in nature. The N2 sorption–desorption experiments showed that the Brunauer–Emmett–Teller (BET) area of the flowerlike microspheres was 32.4 m2 g−1. Some factors influencing the formation of flowerlike Bi2S3 microspheres were investigated, including the reaction temperature, and the sort and amount of the surfactant. The experiments showed that the Bi2S3 micro/nanostructures prepared in the present work could be used as new-type catalysts for the reduction of some aromatic nitro compounds, such as 4-nitroaniline, 2-nitrophenol and 4-nitrophenol. It was found that the as-obtained flowerlike Bi2S3 microspheres contributed to the best catalytic activity.