Accelerated photodeterioration of class I toxic monocrotophos in the presence of one-pot constructed Ag3PO4/polyaniline@g-C3N4 nanocomposite: efficacy in light harvesting.

Water and soil contamination has become unavoidable due to the enormous usage of pesticides in agriculture. Among the pesticides, monocrotophos (MCP), a popular and largely used pesticide, is extremely toxic to birds and humans, which is easily leached into the environment. Therefore, establishment of a green tactic to clean the environment from such hazard is very essential. Herein, we have developed a novel ternary nanocomposite, Ag3PO4/polyaniline@g-C3N4 with enhanced electron-hole separation efficiency, a condition which is very much required for any photocatalyst. The nanocomposite was one-pot synthesized by a simple and economical hydrothermal method. The strategically modulated band gaps of the nanocomposite help harvest the sunlight efficaciously for the robust degradation of MCP (99.6%). It has been found that the active species involved in the photo-cleaning process are OH· and O2·-. A suitable reaction mechanism has been proposed and discussed. Analytical techniques, which include energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), elemental mapping analysis, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), and X-ray diffraction (XRD), were used to characterize the synthesized nanocomposite. This nano-photocatalyst, which is simple, stable, and reusable, certainly has potential applications in soil contamination remediation, sewage treatments, and other environment decontaminations. Also, a study of this kind offers more strategic plans for the production of clean energy (hydrogen) by solar-driven water splitting.

A glassy carbon electrode modified with a copper tungstate and polyaniline nanocomposite for voltammetric determination of quercetin.

A binary nanocomposite of type copper tungstate and polyaniline (CuWO4@PANI) is described that was obtained by single step polymerization on the surface of a glassy carbon electrode (GCE). The resulting electrode is shown to be a viable tool for voltammetric sensing of quercetin (Qn) in blood, urine and certain food samples. The nanocomposite was characterized by UV-visible absorption spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and high-resolution transmission electron microscopy. Differential pulse voltammetry was applied to quantify Qn, typically at the relatively low working potential of 0.15 V (vs. Ag/AgCl). The modified GCE has a wide analytical range (0.001-0.500 µM) and a low detection limit (1.2 nM). The sensor is reproducible, selective and stable. This makes it suitable for determination of Qn in real samples without complicated sample pretreatment. Graphical abstract Schematic of a copper tungstate and polyaniline nanocomposite modified glassy carbon electrode for voltammetric determination of quercetin in real samples.

New Electrochemical Sensor Based on a Silver-Doped Iron Oxide Nanocomposite Coupled with Polyaniline and Its Sensing Application for Picomolar-Level Detection of Uric Acid in Human Blood and Urine Samples.

A simple and very sensitive electrochemical sensor for the detection of uric acid (UA) has been developed based on polyaniline (PANI) merged into a silver-doped iron oxide (Ag-Fe2O3) nanocomposite-modified glassy carbon electrode. The synthesized ternary composite material (Ag-Fe2O3@PANI) was characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray, High-resolution transmission electron microscopy, X-ray diffraction, and thermo gravimetric analysis analyses. The nanocomposite-modified electrode shows an exceptional electrocatalytic activity and reversibility to the oxidation of UA in a 0.1 M phosphate buffer solution (pH 7.0) compared to those in PANI and Ag-Fe2O3. The detection limit of UA is found to be 102 pM with a linear dynamic range of 0.001-0.900 µM. The fabricated UA sensor also exhibits good selectivity, reproducibility, and long-time stability. The limit of detection and linear range attained for the synthesized composite are much greater compared to those of any other composite materials reported in the literature. The proposed method has been successfully applied for the selective detection of UA in various real samples such as human serum and urine with good recoveries. This platform that assimilates such electrocatalytic ternary nanocomposite with high performance can be widely employed for fabricating diverse sensors.

A novel photocatalytically active mesoporous metal-free PPy grafted MWCNT nanocomposite.

A new mesoporous metal-free functionalized multi-walled carbon nanotube (f-MWCNT) covalently grafted polypyrrole (PPy) nanocomposite has been synthesized via chemical oxidative polymerization method keeping different weight ratio of f-MWCNT (1-4). Various instrumentation techniques such as UV-DRS, FT-IR, XRD, Raman, TGA, BET and TEM were used to characterize the as-prepared nanocomposite. The successfully constructed photocatalytically active mesoporous metal-free PPy grafted MWCNT nanocomposite was employed for the decontamination of nitrobenzene (NB). Among all the catalysts, f-MWCNT-PPy (3) is found to be efficient due to a large specific surface area and high pore volume by which 99.9% reduction has been achieved within 60 min. The obtained mesoporous, covalently grafted and synergistic f-MWCNT-PPy can be used as an efficient and recyclable photocatalyst for the degradation of organic contaminants from wastewater. Also, study of this kind will undoubtedly expedite new researches on solar-driven water splitting.

Efficacious separation of electron-hole pairs in CeO2-Al2O3 nanoparticles embedded GO heterojunction for robust visible-light driven dye degradation.

Herein, we have developed a facile and one pot synthesis of ternary CeO2-Al2O3@GO nanocomposite via wet chemical method. The structural and morphological characteristics of the synthesized nanocomposite was investigated using UV-DRS, FT-IR, XRD, FE-SEM, HR-TEM, EDX and TGA analysis. The CeO2-Al2O3@GO composite was tested for its ability to photocatalytically degrade Rhodamine B (RhB) under visible light illumination. The influence of various operational parameters such as pH, catalyst dosage and initial dye concentration on the photo degradation was investigated in detail. The synthesized CeO2-Al2O3@GO composite shows greater photocatalytic degradation of RhB (99.0%) under visible light irradiation than the raw CeO2, Al2O3, and GO catalysts and any other reported nanocomposite materials. The recyclability results also demonstrate the excellent stability and reusability of the CeO2-Al2O3@GO nanocomposite. This work will be beneficial in the field of industrial and engineering applications in the degradation of organic pollutants. Also, a study of this kind will definitely stimulate many researches in the recently emerging field of solar-driven water splitting.

Morphology dependent nonlinear optical and photocatalytic activity of anisotropic plasmonic silver.

Anisotropic nanoparticles are ideal building blocks for a number of functional materials due to their exceptional and anisotropic optical, electronic, magnetic and mechanical properties. In this work we present systematic studies on morphology dependent ultra-sensitive thermal diffusivity and photodegradation capability of anisotropic plasmonic silver for the first time. Hydrogen peroxide centered synthesis was performed to prepare anisotropic silver nanosystems spherical (14 nm), quasi-spherical (17 nm), elliptical (18 m), rods (aspect ratio 2.1), hexagonal (22 nm) and prisms (19 nm). The synthesized nanosystems were characterized using UV-VIS spectroscopy, high resolution transmission electron microscopy (HRTEM) and band gap analysis. A dual beam mode matched thermal lensing method was adopted for evaluating the thermal diffusivity of the anisotropic system. The present anisotropic nanoparticle system exhibited strong morphology based thermal diffusivity. An increase of 140% in the thermal diffusivity value points to the nonlinear optical application potential of the anisotropic systems. Sunlight mediated photodegradation of methylene blue showed a promising increase in the degradation rate for anisotropic systems compared to other similar systems reported in the literature.

Antibacterial efficacy of silver nanoparticles against multi-drug resistant clinical isolates from post-surgical wound infections.

In order to investigate new effective and inexpensive nano-therapeutic approach for P. aeruginosa, staphylococcus aureus and coagulase negative staphylococci (CoNS), the present study reports an eco-friendly process for rapid synthesis of silver nanoparticles (Ag-NPs) using aqueous leaf extract of Corchorus Capsularis (CRCP). Formation of stable Ag-NPs at different time intervals gives mostly spherical particles with diameters ranging from 5 to 45 nm. The resulting Ag-NPs were characterized using Ultraviolet visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD) analysis, Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray analysis (EDX). XRD study shows that the particles are crystalline in nature with face centered cubic geometry. TEM studies show the formation of Ag-NPs with average size of 20.52 nm. The antimicrobial activity of the synthesized Ag-NPs was investigated against multi drug resistant (MDR) P. aeruginosa, Staphylococcus aureus and CoNS isolates from post-surgical wound infections. The present study suggests that Ag-NPs synthesized from aqueous leaf extract of CRCP shows significant antibacterial potential against MDR isolates from post-surgical wound infections.

Evaluation of a New Biosensor Based on in Situ Synthesized PPy-Ag-PVP Nanohybrid for Selective Detection of Dopamine.

In the present work, in situ synthesis of polypyrrole-silver-polyvinylpyrrolidone (PPy-Ag-PVP) nanohybrid using AgNO3 as an oxidant and polyvinylpyrrolidone (PVP) as a stabilizer and surfactant is demonstrated. The obtained ternary PPy-Ag-PVP nanohybrid was characterized by UV-vis, FT-IR, XRD, Raman, TGA, SEM, and HR-TEM analysis. Further the synthesized PPy-Ag-PVP has been investigated for its selective and sensitive sensing of dopamine (DA). The PPy-Ag-PVP modified glassy carbon electrode shows a reversible electrochemical behavior with superior response for DA. The limit of detection and limit of quantification are found to be 0.0126 and 0.042 µM (S/N = 3 and 10), respectively, with remarkable sensitivity (7.26 µA mM-1 cm-2). The practical application of the present modified electrode has been validated by determining the concentration of DA in human urine samples of different age group.

A simple electrochemical platform for detection of nitrobenzene in water samples using an alumina polished glassy carbon electrode.

In this work, we report a selective electrochemical sensing of nitrobenzene (NB) using an alumina (γ-Al2O3) polished glassy carbon electrode (GCE) for the first time. The scanning electron microscopy studies confirm the presence of alumina particles on the GCE surface. X-ray photoelectron spectroscopy studies reveal that the utilized alumina is γ-Al2O3. The alumina polished GCE shows an enhanced sensitivity and lower overpotential toward the reduction of NB compared to unpolished GCE. The differential pulse voltammetry response was used for the determination of NB and it shows that the reduction peak current of NB is linearly proportional to the concentrations of NB ranging from 0.5 to 145.5µM. The limit of detection is found to be 0.15µM based on 3σ. The fabricated electrode exhibits its appropriate selectivity towards NB in the presence of a range of nitro compounds and metal ions. The good practicality of the sensor in various water samples reveals that it can be a promising electrode material for practical applications. In addition, the proposed NB sensor is simple and cost effective one when compared with previously reported NB sensors in the literature.