Reproducible Chemical Sensor Research Articles

Highly Sensitive Picric Acid Chemical Sensor Based on Samarium (Sm) Doped ZnO Nanorods.

Herein, we report the synthesis, characterization and picric acid chemical sensing application of samarium (Sm) doped ZnO nanorods. The Sm-doped ZnO nanorods were synthesized by facile hydrothermal process and characterized using various analytical methods which confirmed the large-scale synthesis and wurtzite hexagonal crystal structure for the synthesized nanorods. The doping of Sm ions in the lattices of the synthesized nanorods was evaluated by the energy dispersive X-ray spectroscopy (EDS). The synthesized Sm-doped ZnO nanorods were used as potential scaffold to fabricate high sensitive and reproducible picric acid chemical sensor based on I-V technique. The fabricated picric acid chemical sensor based on Sm-doped ZnO nanorods exhibited a high sensitivity of 213.9 mA mM-1 cm-2 with the limit of detection of ∼0.228 mM and correlation coefficient of R═0.9889. The obtained results revealed that the facile grown Sm-doped ZnO nanorods can efficiently be used to fabricate high sensitive and reproducible chemical sensors.

Sm2O3-doped ZnO beech fern hierarchical structures for nitroaniline chemical sensor

Sm2O3-doped ZnO hierarchical composites were prepared via a facile, simple hydrothermal method using Zn(CH3COO)2.2H2O and Sm(NO3)30.6H2O as precursors. Growth temperature, time, and pH for the reaction were 7h, 155°C and 9.5, respectively. Needle-shaped and compound leaf-shaped structures with ovate or triangular-ovate outlines similar to those of Beech Fern (Phegopteris hexagonoptera) for hierarchical composites were formed. Further, the synthesized Sm2O3-doped ZnO hierarchical composites were used as efficient electron mediators for the preparation of highly sensitive, fast and reliable nitroaniline electrochemical sensors. A sensitivity of 1.71μAμM−1cm−2 with a very low experimental detection limit of 15.6μM was reported for Sm2O3-doped ZnO hierarchical composites modified Ag electrode. Thus, as synthesized Sm2O3-doped ZnO hierarchical composites are potential and efficient electron mediators for the fabrication of sensitive, reliable and reproducible chemical sensors.

Sb2O3–ZnO nanospindles: A potential material for photocatalytic and sensing applications

This paper reports the facile synthesis, characterization and applications of Sb2O3–ZnO nanospindles. The nanospindles were synthesized by facile diethanolammine assisted hydrothermal process and characterized in detail in terms of their morphological, structural, compositional and optical properties. The detailed characterizations revealed that the prepared nanoellipsoids are well-crystalline, grown in high density and possessing good optical properties. Further, the as-synthesized Sb2O3–ZnO nanospindles were found to be an efficient photocatalyst for the degradation of methylene blue (MB) dye under UV light. Sb2O3–ZnO nanospindles were also used as an efficient electron mediator to fabricate a robust, highly sensitive and reproducible chemical sensor for the detection of thiourea in aqueous medium. The fabricated chemical sensor possesses high sensitivity of 6.54µAmmolL−1cm−2. The sensing calibration plot was found to be linear (R2=0.91423) over the large concentration range from 1.56mmolL−1 to 100mmolL−1. The obtained results confirmed that the Sb2O3–ZnO nanospindles may hold great potential for the removal of organic pollutants and for monitoring of thiourea in aqueous solution.

TiO2 nanotube arrays via electrochemical anodic oxidation: Prospective electrode for sensing phenyl hydrazine

The TiO2 nanotube (NT) arrays were grown on Ti foil substrate by electrochemical anodic oxidation and utilized as working electrode to fabricate a highly sensitive and reproducible chemical sensor for the detection of harmful phenyl hydrazine chemical. The fabricated chemical sensor based on TiO2 NT arrays electrode exhibited high sensitivity of ∼40.9μA mM−1 cm−2 and detection limit of ∼0.22 μM with short response time (10 s). The enhanced sensing properties were attributed to the presence of depleted oxygen layer on the surface of grown TiO2 NT arrays and its high electron transfer process via good electrocatalytic activity towards phenyl hydrazine chemical.

A sea-cucumber-like hollow polyaniline spheres electrode-based chemical sensor for the efficient detection of aliphatic alcohols

Sea-cucumber-like hollow polyaniline (PANI) spheres were synthesized by the chemical polymerization of aniline monomers in the presence of salicyclic acid. The synthesized sea-cucumber-like hollow PANI spheres were applied as a working electrode for the fabrication of highly sensitive, reliable and reproducible chemical sensors for detecting ethanol and other alcohols. The sea-cucumber-like hollow PANI spheres were extensively characterized in terms of their morphological, structural, optical, electrical and electrochemical properties. The morphological characterization revealed a sea-cucumber-like hollow morphology with a uniform decoration of nanofibrils covering the shell of the spheres. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements were performed to elucidate the electrochemical behavior of sea-cucumber-like hollow PANI spheres electrode towards the detection of aliphatic alcohols. The sensing performances of the synthesized sea-cucumber-like hollow PANI spheres electrode towards the detection of alcohols were analyzed by the current (I)–voltage (V) characteristics. The sea-cucumber-like hollow PANI spheres electrode based ethanol chemical sensor showed considerably high sensitivity of ∼426.5 μA mM−1 cm−2 and a detection limit of ∼515.7 μM with a correlation coefficient (R) of ∼0.90157 and a short response time (10 s).

A highly sensitive ammonia chemical sensor based on α-Fe2O3 nanoellipsoids

This paper reports the facile synthesis of α-Fe2O3 nanoellipsoids by a low-temperature hydrothermal process and their effective utilization in the fabrication of a highly sensitive aqueous ammonia chemical sensor by the I–V technique. The as-synthesized α-Fe2O3 nanoellipsoids are characterized in terms of their morphological, structural and optical properties. The detailed structural and optical properties confirm a rhombohedral α-Fe2O3 structure and indirect (1.87 eV) and direct (2.15 eV) band gaps, respectively, for the synthesized nanoellipsoids. The fabricated aqueous ammonia sensor based on nanoellipsoids exhibits a very high and reproducible sensitivity of ∼4.678 µA cm−2 mM−1 and a detection limit of ∼0.04 nM with a correlation coefficient (R) of 0.995 in a short response time (10.0 s). The presented work demonstrates that simply synthesized iron oxide nanostructures can efficiently be used for the fabrication of reliable and reproducible chemical sensors.