Significantly enhanced temperature-dependent selectivity for NO2 and H2S detection based on In2O3 nano-cubes prepared by CTAB assisted solvothermal process

This work is a comprehensive review of sensing materials, which interact with several target gases pertinent to agricultural monitoring applications. Sensing materials which interact with carbon dioxide, water vapor (relative humidity), hydrogen sulfide, ethylene and ethanol are the focus of this work. Performance characteristics such as dynamic range, recovery time, operating temperature, long-term stability and method of deposition are discussed to determine the commercial viability of the sensing materials considered in this work. In addition to the sensing materials, deposition methods are considered to obtain the desired sensing material thickness based on the sensor’s mechanism of operation. Various material classes including metal oxides, conductive polymers and carbon allotropes are included in this review. By implementing multiple sensing materials to detect a single target analyte, the issue of selectivity due to cross sensitivity can be mitigated. For this reason, where possible, it is desirable to utilize more than one sensing material to monitor a single target gas. Among those considered in this work, it is observed that PEDOT PSS/graphene and TiO2-coated g-C3N4 NS are best suited for CO2 detection, given their wide dynamic range and modest operating temperature. To monitor the presence of ethylene, BMIM-NTf2, SWCNTs and PtTiO2 offer a dynamic range most suitable for the application and require no active heating. Due to the wide dynamic range offered by SiO2/Si nanowires, this material is best suited for the detection of ethanol; a gas artificially introduced to prolong the shelf life of the harvested crop. Finally, among all other sensing materials investigated, it observed that both SWCNTs and CNTs/SnO2/CuO are most suitable for H2S detection in the given application.

suspension, followed by drying at 120 °C [ 55 ].…”

Section: Deposition Methodsmentioning

confidence: 99%

“…Under the metal oxide material class, Li et al used indium oxide (In

) nano-cubes for sensing H

S at room 25 °C and 100 °C [ 55 ]. Synthesis of this material involved a cetyltrimethyl ammonium bromide (CTAB)-assisted solvothermal and subsequent calcination process.…”

Section: Sensing Materials For Target Analyte Detectionmentioning

confidence: 99%

A Review on Advanced Sensing Materials for Agricultural Gas Sensors

Love

Nazemi

El-Masri

et al. 2021

“…Metal oxide resistive-type NO 2 sensors have attracted a significant amount of attention due to their high performance ability. Metal oxide exhibits excellent gas sensitive properties due to its high specific surface area and enhanced surface reactivity [ 5 , 6 , 7 , 8 ]. In addition, the high operating temperatures of some metal oxide-based sensors can lead to increases in power consumption and reductions in the lifetime of sensors [ 5 , 6 , 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

“…Metal oxide exhibits excellent gas sensitive properties due to its high specific surface area and enhanced surface reactivity [5][6][7][8]. In addition, the high operating temperatures of some metal oxide-based sensors can lead to increases in power consumption and reductions in the lifetime of sensors [5][6][7][8][9]. Metal oxide resistive-type NO 2 sensors are also simple and inexpensive to manufacture.…”

Section: Introductionmentioning

confidence: 99%

Magnesium Zirconate Titanate Thin Films Used as an NO2 Sensing Layer for Gas Sensor Applications Developed Using a Sol–Gel Method

Huang

Lee

Wang

2021

Magnesium zirconate titanate (MZT) thin films, used as a sensing layer on Al interdigitated electrodes prepared using a sol–gel spin-coating method, are demonstrated in this study. The p-type MZT/Al/SiO2/Si structure for sensing NO2 is also discussed. The results indicated that the best sensitivity of the gas sensor occurred when it was operating at a temperature ranging from 100 to 150 °C. The detection limit of the sensor was as low as 250 ppb. The sensitivity of the MZT thin film was 8.64% and 34.22% for 0.25 ppm and 5 ppm of NO2 gas molecules at a working temperature of 150 °C, respectively. The gas sensor also exhibited high repeatability and selectivity for NO2. The response values to 250, 500, 1000, 1500, 2000, 2500, and 5000 ppb NO2 at 150 °C were 8.64, 9.52, 12, 16.63, 20.3, 23, and 34.22%, respectively. Additionally, we observed a high sensing linearity in NO2 gas molecules. These results indicate that MZT-based materials have potential applications for use as gas sensors.

“…Among them, gas sensors made by semiconductors, especially metal oxide semiconductors (MOS), have attracted extensive attention due to their advantages of environmental protection, simple preparation, low cost, and good stability [ 12 , 13 , 14 ]. Among a large number of MOS materials, In 2 O 3 , as a typical n-type semiconductor material, has become a hot research topic due to its wide bandgap width and low resistivity, and has been widely used in liquid crystal devices, solar cells, and gas sensors [ 15 , 16 , 17 ]. By referring to the previous research results, it has been found that In 2 O 3 nanomaterials show good gas sensing response to both oxidation and reductive gases, so In 2 O 3 is a gas-sensitive material with great research potential.…”

Section: Introductionmentioning

confidence: 99%

Ethanol Sensors Based on Porous In2O3 Nanosheet-Assembled Micro-Flowers

Qin

Yuan

Gao

et al. 2020

By controlling the hydrothermal time, porous In2O3 nanosheet-assembled micro-flowers were successfully synthesized by a one-step method. The crystal structure, microstructure, and internal structure of the prepared samples were represented by an x-ray structure diffractometry, scanning electron microscopy, and transmission electron microscopy, respectively. The characterization results showed that when the hydrothermal time was 8 h, the In2O3 nano materials presented a flower-like structure assembled by In2O3 porous nanosheets. After successfully preparing the In2O3 gas sensor, the gas sensing was fully studied. The results show that the In2O3 gas sensor had an excellent gas sensing response to ethanol, and the material prepared under 8 h hydrothermal conditions had the best gas sensing property. At the optimum working temperature of 270 °C, the highest response value could reach 66, with a response time of 12.4 s and recovery time of 10.4 s, respectively. In addition, the prepared In2O3 gas sensor had a wide detection range for ethanol concentration, and still had obvious response for 500 ppb ethanol. Furthermore, the gas sensing mechanism of In2O3 micro-flowers was also studied in detail.