Room Temperature Ammonia Gas Sensor Based on p-Type-like V2O5 Nanosheets towards Food Spoilage Monitoring

Abstract

Gas sensors play an important role in many areas of human life, including the monitoring of production processes, occupational safety, food quality assessment, and air pollution monitoring. Therefore, the need for gas sensors to monitor hazardous gases, such as ammonia, at low operating temperatures has become increasingly important in many fields. Sensitivity, selectivity, low cost, and ease of production are crucial characteristics for creating a capillary network of sensors for the protection of the environment and human health. However, developing gas sensors that are not only efficient but also small and inexpensive and therefore integrable into everyday life is a difficult challenge. In this paper, we report on a resistive sensor for ammonia detection based on thin V2O5 nanosheets operating at room temperature. The small thickness and porosity of the V2O5 nanosheets give the sensors good performance for sensing ammonia at room temperature (RT), with a relative change of resistance of 9.4% to 5 ppm ammonia (NH3) and an estimated detection limit of 0.4 ppm. The sensor is selective with respect to the seven interferents tested; it is repeatable and stable over the long term (four months). Although V2O5 is generally an n-type semiconductor, in this case the nanosheets show a p-type semiconductor behavior, and thus a possible sensing mechanism is proposed. The device’s performance, along with its size, low cost, and low power consumption, makes it a good candidate for monitoring freshness and spoilage along the food supply chain.

Sensitive and Reversible Ammonia Gas Sensor Based on Single-Walled Carbon Nanotubes

“…In this investigation, detection levels were reached in the ppb range, although high working temperatures were required [26]. In another investigation, an ammonia sensor based on V2O5 nanosheets was developed [27]. In this case, the sensor was able to work at room temperature, showing high sensitivity and low detection limit even in the presence of interfering gases such as methanol, ethanol and others.…”

Effect of synthesis parameters on cobalt oxide nanostructures morphology

“…The resulting sensor was annealed in air at 400˚C for 2 hours to enhance the stability of the material and improve adhesion between the material and the electrodes. The electrical resistance of the sensor was monitored using a Keithley 2602B source meter (Keithley, Solon, OH, USA) during cyclic exposure of NH 3 diluted in air (baseline gas) with the assistance of mass flow controllers (Kofloc, 3660, Korea) [24]. Pulses with analyte concentrations varying from 25 to 500 ppm were released, and the total gas flow was maintained at a constant rate of 400 sccm throughout the measurements.…”

Nondestructive Technique for Identifying Adulteration and Additives in Lemon Juice Based on Analyzing Volatile Organic Compounds (VOCs)

“…Using a sensor array, this system simulates the human sense of smell and attempts to determine the effects of odors on the headspace of samples [22,23]. Gas sensors play an important role in many areas of human life, including the monitoring of production processes, occupational safety, food quality assessment, and air pollution monitoring [24]. Essentially, an electronic nose is a device that includes a multisensor array and multidimensional signal processing through pattern recognition algorithms that can detect the presence of volatile compounds associated with food aromas [25].…”