Solid-state synthesis strategy of ZnO nanoparticles for the rapid detection of hazardous Cl2

Abstract

In the present study, rapid and highly efficient solid-state synthesis strategy has been successfully employed for the synthesis of zinc oxide nanoparticles (ZnO NPs). Herein, prepared ZnO NPs are characterized and used for the fabrication of highly sensitive, selective, and accountable gas sensors. Structural elucidation, surface composition, and morphological investigations of as-synthesized ZnO NPs respectively, are carried out using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction measurement techniques. The gas sensing properties of ZnO NPs studied at various operating temperatures and towards

Solution-processed rapid synthesis strategy of Co3O4 for the sensitive and selective detection of H2S

“…3(a)] has revealed that these flowers are composed of a large number of individual nano-needles clustered together so that they can form the aforementioned Co 3 O 4 micro-dandelions. Such kind of interconnected network of Co 3 O 4 micro-dandelions offers more porosity followed pathways than a dense type surface morphology, as it has a higher surface area to volume ratio, making it more appropriate for gas sensing applications, as higher surface areas maximizes the surface reactions and, consequently, increases the sensor response values [5,21]. In addition, the fluffy nature of the system, having large open spaces existing between the individual nano-needles, permits effortless diffusion of gas molecules into the inner region of the micro-dandelions.…”

“…The selectivity bar chart clearly shows that the At 200 °C, these two competing processes are in an optimum level. On the one hand, the H 2 S gas molecules possess sufficient thermal energies to interact with adsorption oxygen species and on the other hand the prevention or the immediate desorption due to excessive thermal energy, thus, sensor reaches to its best response value [5,25,26]. The temperature dependent response study has revealed that the Co 3 O 4 films exhibit its maximum response value to H 2 S @200 °C, therefore 200 °C is considered as an optimized working temperature of the sensor and the same was applied for further studies.…”

“…In present study, rapid increase in resistance value after the interaction of H 2 S with Co 3 O 4 micro-dandelions film is observed, which is caused by the adsorption/desorption process of H 2 S on the surface of Co 3 O 4 film. It is well-known that the chemiresistive gas sensing mechanism of metal oxide semiconductors is mainly associated with the change in electrical resistance of the sensing material, which is predominantly initiated as a result of adsorption/desorption activities of variety of target gas molecules [5]. The interaction between Co 3 O 4 sensor film and H 2 S gas was described with the help of energy band diagram shown in Fig.7 [27][28][29][30].…”

“…As a result development of simple and cost-effective efficient chemical sensor systems, in order to detect toxic H 2 S at the low concentration level, is crucial for both human health and environmental safety purposes [1,4]. Traditional metal oxide semiconductors, such as cobalt oxide (Co 3 O 4 ), nickel oxide (NiO), iron oxide (Fe 2 O 3 ), indium oxide (In 2 O 3 ), titanium oxide (TiO 2 ), zinc oxide (ZnO), tungsten oxide (WO 3 ), and tin oxide (SnO 2 ) etc., have so far been considered as one of the extensively studied group of chemiresistive gas sensors in the past decades because of their easy fabrication process, low-costs, non-toxic nature, simplicity in use, power consumption, and flexibility in detecting broad range of toxic and hazardous oxidizing and reducing gases under diverse conditions [1,[3][4][5][6][7]. Among various traditional metal oxide semiconductors, Co 3 O 4 , one of the eco-friendly p-type transitional metal oxide materials, which has attracted more attention of researchers because of its wide range of applications such as gas sensors, supercapacitors, Liion batteries, magnetic materials, and heterogeneous catalysts [8][9][10][11][12].…”

Continuous hydrothermal flow-inspired synthesis and ultra-fast ammonia and humidity room-temperature sensor activities of WO3 nanobricks

“…The gas sensor recovery was measured by exposing atmospheric air in sensing chamber, confirmed an excellent recovery in just 5 s. The 8/5 s response/recovery time of the WO 3 NBs film sensor represented its ultrafast sensing activity for potential commercial viability. The response/recovery time of gas sensors mainly depends on how quick the gas diffuses in/out [29]. The response/recovery time is an imperative parameter for calculating the gas-sensing performance of a material.…”