Novel enzyme-free multifunctional bentonite/polypyrrole/silver nanocomposite sensor for hydrogen peroxide detection over a wide pH range

Precise designs of low-cost and efficient catalysts for the detection of hydrogen peroxide (H2O2) over wide ranges of pH are important in various environmental applications. Herein, a versatile and ecofriendly approach is presented for the rational design of ternary bentonite-silylpropyl-polypyrrole/silver nanoarchitectures (denoted as BP-PS-PPy/Ag) via the in-situ photo polymerization of pyrrole with salinized bentonite (BP-PS) in the presence of silver nitrate. The Pyrrolyl-functionalized silane (PS) is used as a coupling agent for tailoring the formation of highly exfoliated BP-PS-PPy sheet-like nanostructures ornamented with monodispersed Ag nanoparticles (NPs). Taking advantage of the combination between the unique physicochemical properties of BP-PS-PPy and the outstanding catalytic merits of Ag nanoparticles (NPs), the as-synthesized BP-PS-PPy/Ag shows a superior electrocatalytic reduction and high-detection activity towards H2O2 under different pH conditions (from 3 to 10). Intriguingly, the UV-light irradiation significantly enhances the electroreduction activity of H2O2 substantially, compared with the dark conditions, due to the high photoelectric response properties of Ag NPs. Moreover, BP-PS-PPy/Ag achived a quick current response with a detection limit at 1 μM within only 1 s. Our present approach is green, facile, scalable and renewabl

Facile preparation of N-S co-doped graphene quantum dots (GQDs) from graphite waste for efficient humidity sensing

In this work, graphene quantum dots (GQDs) were prepared from Graphitic waste. The resulting GQDs were evaluated for the potential application for resistive humidity sensors. The resistive humidity sensors were fabricated on the pre-patterned interdigital ITO electrodes using the three different concentrations (2.5, 5.0, and 10 mg) of GQDs in DMF. The GQDs films were deposited using the spin coating technique. The GQDs (10 mg/ml) based impedance sensors showed good sensitivity and lowered hysteresis as compared to the other ratios (2.5 and 5 mg) of the GQDs. The maximum calculated hysteresis of the GQDs (10 mg) based humidity sensor is around 2.2 % at 30%RH, and the minimum calculated hysteresis of the GQDs (10 mg/ml) based humidity sensor is approximately 0.79 % at 60 %RH. The response and recovery time found to be 15 s and 55 s, respectively. The interesting humidity-dependent resistive properties of these prepared GQDs make them promising for potential application in humidity sensing.Scopu

Grafting of 4-pyrrolyphenyldiazonium in situ generated on NiTi, an adhesion promoter for pyrrole electropolymerisation?

The present work investigates the grafting of in situ generated 4-pyrrolyphenyldiazonium (Py-PD) on NiTi by two different ways. The first way is the electrografting of Py-PD while the second one is the grafting without electrochemistry at room temperature (spontaneous grafting) or under heating (either conventional heating or induction heating). Both modification routes led to the successful grafting of Py-PD. The hypothesis of a cationic intermediate is proposed for the grafting without electrochemistry since it is thermally activated and the oxidized surface of NiTi is not a reductant. For both modification approaches, the TiO2 surface layer of NiTi has been preserved and the NiTi corrosion resistance improved, an important parameter to preserve/improve the NiTi biocompatibility. The second part of the work is dedicated to the electropolymerization of pyrrole on modified surfaces with the Py-PD as adhesion promoter

Bentonite-decorated calix [4] arene: A new, promising hybrid material for heavy-metal removal

There is global concern about the contamination of ground, river, and tap waters as well as soil contamination with heavy metal ions; these chemical species are known to not degrade and to cause severe health problems if ingested by humans and animals. Such environmental and health concerns necessitate the development of ultrasensitive sensors and high-capacity adsorbents. This study demonstrates for the first time the potential of organophilic bentonite combined with tetra(2-pyridylmethyl)amide calix [4] arene as a high-performance hybrid material for the removal of toxic heavy metals. After consecutive synthesis steps, the modified bentonites were thoroughly characterized by FT-IR, XRD, UV spectroscopy, and TEM. In particular, the XRD analysis showed strong supporting evidence for intercalation in the clay following each modification step. The salient feature of the newly prepared hybrid material is its high extraction capacity for Cd(II) and Zn(II) metals, as determined by atomic absorption spectrometry and UV spectrometry. Different preparation methods, with respect to the quantity of the added cationic surfactant, were investigated to determine the optimal conditions for synthesis. The extraction percentage for the as-prepared hybrid material was measured to be as high as 97.4% and 94.2% for Cd(II) and Zn(II), respectively.This paper was made possible by the NPRP award [ 8-878-1-172 ] from Qatar National Research Fund (a member of the Qatar foundation ). The statements made herein are solely the responsibility of the Authors

High-power laser-patterning graphene oxide: A new approach to making arbitrarily-shaped self-aligned electrodes

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The role of diazonium interface chemistry in the design of high performance polypyrrole-coated flexible ITO sensing electrodes.

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Anti-corrosive and oil sensitive coatings based on epoxy/polyaniline/magnetite-clay composites through diazonium interfacial chemistry

Epoxy polymer nanocomposites filled with magnetite (Fe3O4) clay (B), named (B-DPA-PANI@Fe3O4) have been prepared at different filler loading (0.1, 0.5, 1, 3, 5 wt. %). The surface modification of clay by polyaniline (PANI) is achieved in the presence of 4-diphenylamine diazonium salt (DPA). The effects of the nanofiller loading on Tensile, mechanical and dielectric properties were systematically studied. Improved properties was highlighted for all reinforced samples. The addition of only 3 wt. % of the filler enhanced the tensile strength of the composites by 256%, and the glass transition temperature Tg by 37%. The dielectric spectra over a broad frequency showed a robust interface between the hybrid (B-DPA-PANI@Fe3O4) fillers and epoxy matrix. The results showed most significant improvement in corrosion inhibition using electrochemical impedance spectroscopy (EIS) in 3.5 wt % NaCl, as well as a significant response in oil sensing test. High charge transfer resistance of 110 � 106 ?.cm2 using 3-wt % of filler was noted compared to 0.35 � 106 ?.cm2 for the pure epoxy. The results obtained herein will open new routes for the preparation of efficient anticorrosion sensor coatings. � 2018, The Author(s).The NPRP Award [8-878-1-172] from the Qatar National Research Fund (a member of Qatar Foundation) made this manuscript possible.Scopu

A novel fluorescent sensor based on electrosynthesized benzene sulfonic acid-doped polypyrrole for determination of Pb (II) and Cu (II)

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Versatile molecular glues for sticking conductive polymers to flexible electrodes.

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