Electrochemical Detection Of 4-nitrophenol Research Articles

Tetraphenylporphyrin Decorated Bi2MoO6 Nanocomposite: Its Twin Affinity of Oxygen Reduction Reaction and Electrochemical Detection of 4-Nitrophenol.

A selective electrode for oxygen reduction reaction (ORR) and electrocatalytic reduction of 4-nitrophenol (p-NP) was fabricated on a glassy carbon electrode using organic-inorganic Bi2MoO6/H2TPP nanocomposites with different weight percentages of tetraphenylporphyrin, synthesized by the solvothermal process. Materials thus synthesized were characterized through UV-Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. The electrocatalytic performance of the modified electrode toward ORR in the 0.1 M KOH solution, the onset potential Eonset (0.942 V), E1/2 (0.704 V) vs RHE, Jd (-5.545 mA cm-2), and n = 4 physicochemical parameters were well appreciable. It exhibits good catalytic activity toward ORR through a four-electron pathway with excellent stability and high active site density, and thus, the in situ Porphy-decorated metal oxide system facilitates the electron transport process. High selectivity and efficacy for the oxygen reduction reaction (ORR) are a significant measure for several energy-converting applications. The decorated electrode, glassy carbon electrode (GCE)/Bi2MoO6/3 wt % Porphy, serves as an electrochemical sensor that exhibited good sensitivity (0.4683 μAμM-1 cm-2), good reproducibility, a low detection limit (0.0940 μM), and long-term stability in the aqueous phase without any appreciable effect in the presence of some common organic and inorganic interferences for the detection of p-NP in a linear concentration range of 0.5-350 μM. Therefore, the material performs as an effective electrode for both the ORR and the electrocatalytic reduction of p-NP with real matrix samples at room conditions.

Nanostructured Copper Bismuth Oxide for Sensitive and Selective Electrochemical Detection of 4-Nitrophenol

Nanostructured Copper Bismuth Oxide for Sensitive and Selective Electrochemical Detection of 4-Nitrophenol

Electrochemical Detection of 4-Nitrophenol by Using Graphene Based Nanocomposite Modified Glassy Carbon Electrodes: A Mini Review

This article describes the fabrication of electrochemical devices for the detection of a key environmental pollutant, 4-Nitrophenol (4-NPh). 4-NPh is a requirement for the synthesis of organophosphate pesticides. These pesticides are mostly used in the agricultural sector to obtain a high yield of agricultural products. The use of 4-NPh in the agricultural field results in poisonous levels of this compound in the soil and water. Different techniques have been used for its transformation by biological and chemical degradation. However, these strategies not only created highly toxic pollutant but also need fast operation and time consuming processes. In this background, we have reported a broad and efficient review of the electrochemical reduction of 4-NPh as a feasible alternate method. In this review paper, graphene oxide (GO), reduced graphene oxide (rGO), N-doped graphene oxide, functionalized graphene oxide, metallic nanoparticles coated graphene oxide, metal oxides covered on rGO, polymer functionalized graphene oxide and hybrids materials functionalized with graphene oxide (hydroxyl apatite and β-cyclodextrin) which have been fabricated on a glassy carbon electrode (GCE) to enhance the electrocatalytic reduction and increase the sensor activity of 4-NPh are discussed. We have also described the effects of a few interfering phenolic pollutants such as aminophenol, hydroquinone, o-nitrophenol (o-NPh), trinitrotoluene, trinitrophenol, 2, 4-dinitrophenol (4-DNPh) and nitrobenzene. In the paper, easy and more effective electrochemical methods for the detection of 4-NPh with graphene- based nanocomposites modified on GCE for 4-NPh detection are summarized and discussed.

Electrodeposited silver amalgam particles on pyrolytic graphite in (spectro)electrochemical detection of 4-nitrophenol, DNA and green fluorescent protein

Catalytic properties and high adsorption affinity of nucleic acids and proteins to silver amalgam electrode surface make this kind of electrified interface perspective for bioanalytical and biomedical applications. For the first time, a basal-plane pyrolytic graphite electrode (bPGE) has been used as a substrate for electrodeposition of silver amalgam particles (AgAPs). Optimization of the resulting composition, surface morphology and electrochemical properties of the AgAPs was done by scanning electron microscopy with energy disperse X-ray spectroscopy, image processing software and voltammetric detection of electrochemically reducible model organic nitro compound, 4-nitrophenol. Spectro-electrochemical applicability of bPGE-AgAP has been demonstrated by electrolysis of 4-nitrophenol. Simultaneous UV–Vis-chronoamperometry provided information on the number of exchange electrons and the reduction rate constants. Preferential adsorption of the fluorescently labelled calf thymus DNA and the green fluorescent protein (GFP) on the surface of AgAPs was observed by fluorescence microscopy. In contrast to previously studied indium-tin oxide and vapour-deposited gold decorated by AgAPs, herein the presented bPGE-AgAP has provided sufficiently wide negative potential window allowing direct electroanalysis of non-labelled DNA and GFP using intrinsic electrochemical signals independently of the fluorescent labelling. The bPGE-AgAP can thus be expected to find application opportunities in protein electrochemistry, (bio)sensor development or in-situ spectro-electrochemical studies.

Ultrasonically assisted synthesis of barium stannate incorporated graphitic carbon nitride nanocomposite and its analytical performance in electrochemical sensing of 4-nitrophenol.

We describe the ultrasonic assisted preparation of barium stannate-graphitic carbon nitride nanocomposite (BSO-gCN) by a simple method and its application in electrochemical detection of 4-nitrophenol via electro-oxidation. A bath type ultrasonic cleaner with ultrasonic power and ultrasonic frequency of 100W and 50Hz, respectively, was used for the synthesis of BSO-gCN nanocomposite material. The prepared BSO-gCN nanocomposite was characterized by employing several spectroscopic and microscopic techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, fourier transform infra-red, field emission scanning electron microscopy, and high resolution transmission electron microscopy, to unravel the structural and electronic features of the prepared nanocomposite. The BSO-gCN was drop-casted on a pre-treated glassy carbon electrode (GCE), and their sensor electrode was utilized for electrochemical sensing of 4-nitrophenol (4-NP). The BSO-gCN modified GCE exhibited better electrochemical sensing behavior than the bare GCE and other investigated electrodes. The electroanalytical parameters such as charge transfer coefficient (α=0.5), the rate constant for electron transfer (ks=1.16s-1) and number of electron transferred were calculated. Linear sweep voltammetry (LSV) exhibited increase in peak current linearly with 4-NP concentration in the range between 1.6 and 50μM. The lowest detection limit (LoD) was calculated to be 1μM and sensitivity of 0.81 μA μM-1 cm-2. A 100-fold excess of various ions, such as Ca2+, Na+, K+, Cl-, I-, CO32-, NO3, NH4+ and SO42- did not able to interfere with the determination of 4-NP and high sensitivity for detecting 4-NP in real samples was achieved. This newly developed BSO-gCN could be a potential candidate for electrochemical sensor applications.

Fabrication of PdAg nanoparticle infused metal-organic framework for electrochemical and solution-chemical reduction and detection of toxic 4-nitrophenol

In this study, we utilized functionalized metal organic frameworks (MOFs) as a host matrix to embed silver and palladium (AgPd) bimetallic nanoparticles. The physicochemical properties of the as-synthesized materials were characterized Via UV, FT-IR, XRD, SEM, TEM, XPS, BET and TGA analysis. The as-synthesized materials presented excellent activities toward the electrochemical detection of 4-nitrophenol and its reduction by NaBH4 under ambient conditions. The constructed sensor displayed selective and sensitive determination of 4-NP in the linear concentration range 100–370 μM with a limit of detection of Σ32 nM. Moreover, because of its high specific surface area, high conductivity, and fast charge transfer ability, the sensor displayed good electrocatalytic activity. Moreover, it exhibited excellent selectivity toward 4-NP in the presence of common interfering species. The synthesized catalyst exhibited good catalytic activity for the reduction of 4-NP. It was reusable for five consecutive cycles without a significant loss in its catalytic activity. The applicability of the constructed sensor was explored via the detection of 4-NP in tap water samples at a recovery of ∼100.97%.

Pd nanospheres decorated reduced graphene oxide with multi-functions: Highly efficient catalytic reduction and ultrasensitive sensing of hazardous 4-nitrophenol pollutant

We illustrate a facile approach for in situ synthesis of Pd-gum arabic/reduced graphene oxide (Pd-GA/RGO) using GA as the reducing agent, which favors the instantaneous reduction of both Pd ions and GO into Pd nanoparticles (NPs) and RGO. From the morphological analysis of Pd-GA/RGO, we observed highly dispersed spherical 5nm Pd NPs decorated over RGO. The as-synthesized Pd-GA/RGO composite was employed for the catalytic reduction and the electrochemical detection of 4-nitrophenol (4-NP), respectively. The catalytic reduction of 4-NP was highly pronounced for Pd-GA/RGO (5min) when compared to Pd NPs (140min) and Pd/RGO (36min). This enhanced catalytic activity was attributed to the synergistic effect of Pd NPs and the presence of various functional groups of GA. Significantly, the fabricated sensor offered a low detection limit (9fM) with a wider linear range (2–80 pM) and long-term stability. The simple construction technique, high sensitivity, and long-term stability with acceptable accuracy in wastewater samples were the main advantages of the developed sensor. The results indicated that the as-prepared Pd-GA/RGO exhibited better sensing ability than the other graphene-based modified electrodes. Therefore, the proposed sensor can be employed as a more convenient sensing platform for environmental and industrial pollutants.