Spherical silver oxide nanoparticles for fabrication of electrochemical sensor for efficient 4-Nitrotoluene detection and assessment of their antimicrobial activity.

This research article reports an economic and affordable microwave-assisted synthesis of spherical silver oxide nanoparticles (Ag2O NPs) (80-90 nm) for an efficient electrochemical sensing of a hazardous organic pollutant 4-nitrotoluene (4-NT). Such well-characterized Ag2O NPs were utilized to modify gold (Au) electrode in order to fabricate Ag2O-NPs/Au sensor to detect 4-NT using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. Ag2O-NPs/Au sensor exhibited a distinguished electrical response as a function of varying 4-NT concentration in neutral medium samples. Ag2O-NPs/Au sensor demonstrated an ultrahigh sensitivity as 15.33 µA (µM)-1 cm-2, a low detection limit of 62.3 nM, and linear response in detection ranges of 0.6-5.9 µM and 37-175 µM. The sensing performance of fabricated Ag2O-NPs/Au sensor is reproducible, reusable, selective in presence of other chemical species, and validated using real samples. The Ag2O/Au sensor had much rapid and easy fabrication process and offered much lower LOD for 4-NT detection than many previously reported sensors. Along with efficient electrochemical activity, the spherical Ag2O NPs also exhibit remarkable antimicrobial activity against harmful gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacteria. Herein projected efficient Ag2O-NPs/Au electrochemical sensor for 4-NT is affordable with the capability of scaling up to perform point-of-care 4-NT testing needed for successful environmental monitoring and water quality assurance.

Microwave-assisted assembly of Ag2O-ZnO composite nanocones for electrochemical detection of 4-Nitrophenol and assessment of their photocatalytic activity towards degradation of 4-Nitrophenol and Methylene blue dye.

4-Nitrophenol (4-NP) is an extensively utilized industrial chemical and one of major toxic water pollutant. Therefore, there is an urgent need to monitor the levels of 4-NP from environmental samples as well as its eradication are extremely important. Keeping this as a motivation, this research for the first-time reports microwave-assisted cost-effective synthesis of silver oxide (Ag2O)-zinc oxide (ZnO) composite nanocones (CNCs, 80-100 nm) for simultaneous electrochemical detection and photodegradation of 4-NP from aqueous solutions. The Ag2O-ZnO CNCs modified gold electrode was fabricated for electrochemical detection of 4-NP. Such fabricated sensor exhibited a sensitivity of 1.6 µA µM-1cm-2, wide linear detection range of 0.4-26 µM & 28-326 µM, and a low limit of detection of 23 nM. The sensor also exhibited good selectivity in real water samples. Also, an outstanding photocatalytic performance of Ag2O-ZnO CNCs was evaluated towards UV-assisted degradation of 4-NP and organic water pollutant dye, methylene blue. The Ag2O-ZnO CNCs exhibited excellent electro- and photocatalytic activities due to the formation of p-n nano-heterojunction comprising of p-type Ag2O and n-type ZnO semiconductor nanoparticles within the composite. Therefore, herein reported smart CNCs can be projected as applied nano-system for cost-effective and rapid simultaneous detection and removal of 4-NP from aqueous solutions. Such nano-system can be useful for industrial application where detection and removal of 4-NP is a key issue to resolve.

A flower-like ZnO-Ag2O nanocomposite for label and mediator free direct sensing of dinitrotoluene.

2,4-Dinitrotoluene (2,4-DNT) is a nitro aromatic compound used as a raw material for trinitrotoluene (TNT) explosive synthesis along with several other industrial applications. Easy, rapid, cost-effective, and selective detection of 2,4-DNT is becoming essential due to its hepato carcinogenic nature and presence in surface as well as ground water as a contaminant. Keeping this in view, this research, for the first-time, reports the synthesis of novel ZnO-Ag2O composite nanoflowers on a gold (Au) substrate, to fabricate an electrochemical sensor for label-free, direct sensing of 2,4-DNT selectively. The proposed ZnO-Ag2O/Au sensor exhibits a sensitivity of 5 µA µM-1 cm-2 with a low limit of detection (LOD) of 13 nM, in a linear dynamic range (LDR) of 0.4 µM to 40 µM. The sensor showed reasonably high re-usability and reproducibility, with reliable results for laboratory and real-world samples.