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To fabricate efficient gas sensors with novel engineered nanomaterials, silver nanoparticles (Ag-NPs) were successfully green synthesized by Nd: YAG nanosecond pulsed laser ablation technique using a mixture of diluted silver nitrate solution and citrus limetta juice extract irradiated for different ablation durations at room temperature. Brownish-yellow colloidal Ag-NPs formation was confirmed by UV-Vis spectroscopy with the absorbance peak around 407-419 nm. HR-TEM results confirmed well mono-dispersed spherical shape morphology for Ag-NPs with particle size around 8 nm for near to 80 min of ablation time. Notably, the engineered nanostructured Ag-NPs were used freshly in room temperature fiber optic gas sensing. The sensor exhibited an outstanding linear response for ammonia gas (0-500 ppm). The sensitivity was about 128.7 Counts/kPa for ammonia gas at RT. The dynamic response of the sensor was recorded to be 15.5 s and 3.5 s. In summary, laser-ablated green synthesized Ag-NPs showed excellent efficiency in detecting ammonia gas at room temperature.

In this work, a simple nonenzymatic glucose sensor has been proposed based on coconut shell charcoal (CSC) modified nickel foil as working electrode in a three-electrode electrochemical cell. Charcoal was prepared by the pyrolysis of coconut shells. The most important advantages of coconut shells are cost-effectiveness and their abundance in nature. The morphology and phase of the CSC powder were characterized by scanning electron microscopy and X-ray diffraction. The electrochemical performance of the CSC powder coated Nickel foil electrode was investigated by cyclic voltammetry and chronoamperometry. The sensor shows a higher sensitivity of 2.992 mA cm−2 mM−1 in the linear range of 0.5–5.5 mM and slightly lower sensitivity of 1.1526 mA cm−2 mM−1 in the range of 7–18.5 mM glucose concentration with a detection limit of 0.2 mM. The anti-interference property of CSC powder also was investigated and found that the response of interfering species was less significant compared to glucose response. The proposed sensor offers good sensitivity, wide linear range, and a very low response to interfering biomolecules.

Ni-doped SnO2 nanoparticles were synthesized by a coprecipitation route and showed superior properties for a series of different applications. The 1 atom % Ni-doped SnO2 NPs exhibited excellent ele...

We report the fiber optic gas-sensing application of hematite microparticles (HMPs) with an average crystallite size of 35 ± 2 nm, which has been synthesized by co-precipitation method. Structure and morphology of the prepared HMPs have been carried out using x-ray diffraction technique (XRD) and scanning electron microscopic techniques, respectively. The XRD pattern reveals that the prepared HMPs exhibit rhombohedral structure and rhomb-centered lattice. Vibrational properties of prepared microparticles have been studied using the Raman and Fourier-transform infrared spectroscopic analysis. The direct–indirect bandgaps and refractive index of the material have been deduced from the UV–Vis absorption spectroscopic analysis. The calculated refractive index indicates that the proposed gas sensor works under leaky mode and has been used for sensing the presence of acetone, ethanol, ammonia and methanol.