Ammonia Sensor Research Articles

Pemanfaatan Narrowband IoT (NB-IoT) dalam Peningkatan Produktivitas Peternakan melalui Monitoring Otomatis

The rapid advancements in Narrowband IoT (NB-IoT) technology present significant opportunities for creating innovative products that can be implemented in daily life. One of these innovative products is the utilization of NB-IoT for monitoring cage conditions, maintenance, and boosting livestock productivity under challenging conditions that are difficult to manually control. This study aims to design an automated system capable of maintaining ideal cage conditions, including temperature, humidity, levels of ammonia (NH3 and CO2), as well as providing feed/water to livestock automatically and periodically. The research methodology involves the integration of various sensors mounted on a microcontroller, such as temperature sensors, humidity sensors, ammonia sensors, water level sensors, and pH sensors. The program executed by this microcontroller is connected to a control panel, and through the internet network, control and monitoring can be carried out using mobile and desktop devices. The test results indicate that this system is capable of providing ease in controlling the chicken coop for owners and workers, maintaining poultry health, and increasing livestock product yields from 97.17% of harvested poultry to 98.263%, with a decrease in the mortality rate from 2.830% to 1.737%. Overall, the utilization of NB-IoT technology in this research provides a positive impact on livestock management, offering an automated solution that enhances efficiency and productivity in the agricultural sector.

Poly(aniline)-based ammonia sensors: Understanding the role of polyurethane on structural/morphological properties and sensing performances

Highly sensitive ammonia (NH3) sensors based on acidic-doped polyaniline (PAni) and polyurethane (PU) are proposed using the facile drop-cast technique. The mass ratios between the polymers were varied in order to elucidate the influence of PU on the film structure and sensing performances of PAni. The supramolecular arrangement changes according to the polymer proportions without impacting the doping of PAni, phenomenon observed in the morphological and optical measurements. The results of the devices showed that the presence of PU can significantly enhance the sensitivity of the sensors without interfering with the main sensing features of PAni, and the proportion variation affects directly the characteristics and performances of the device. We also verified that the PU/PAni sensors present good repeatability and ability to promptly respond to random ammonia concentration variation. Moreover, PU mitigated the influence of humidity on the sensors, which tends to lower their response toward ammonia, and also decreased the drift of the devices which increases their lifespan within a device operating range. The PU/PAni films offer a potential option for applications requiring low-concentration detection of NH3, such as indoor air quality and medical diagnosis.

Highly efficient and cost-effective polyaniline-based ammonia sensor on the biodegradable paper substrate at room temperature

A highly efficient, flexible and cost-effective ammonia (NH3) gas sensor is developed on a biodegradable paper substrate. The polyaniline (PANI) film as an active sensing material was deposited by a simple in-situ polymerization method and optimized for NH3 detection. The PANI film was investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) for structural and morphological properties. The sensor was tested for its efficiency to detect the NH3 gas over the concentration range of 12–1000 ppm at room temperature. The sensor showed excellent repeatability, stability and selectivity towards NH3 detection. At concentrations of 12 ppm (lower level), 200 ppm (intermediate level), and 1000 ppm (higher level), the sensor exhibited effective response values of 3.60, 6.85, and 9.33, respectively. The sensor exhibited a quick response time of 30–9 s when subjected to 12–1000 ppm of NH3. The sensor can detect ammonia gas in real-time, which makes it useful for identifying rapid changes in NH3 concentration. The sensor response was reduced by 5.5% towards 200 ppm NH3 despite a significant variation in relative humidity from 20% to 80%. Based on these results, our flexible PANI sensor is a viable option for efficient and cost-effective on-site NH3 detection.

Waterproof breathable multifunctional flexible sensor for underwater tactile sensing and ammonia gas monitoring

Flexible wearable multifunctional sensors play a vital role in health monitoring, electronic skin, and hazardous gas detection. While combining excellent sensing performance, it is still a challenge to prepare an electronic device with practical properties to increase wearing comfort and adaptability to harsh environments. Herein, we present a multifunctional sensor based on PA6 composite fibers, exhibiting outstanding sensitivity to different external stimuli. For the tactile sensor, we have successfully adjusted the sensitivity and linear range by introducing a spacer layer to improve the linearity by 21.6 times. Benefiting from its intricate and rich fiber structure, the multi-layer fiber-based ammonia sensor has a high sensitivity and a lower detection limit. The multifunctional sensor leverages the dual properties of its outer hydrophobic PA6/PS composite fibers and inner hygroscopic PA6 nanofibers, effectively bolstering its resistance to humidity. Furthermore, the breathability and waterproofness make the sensor promising for rainfall monitoring, underwater pulse/behavior monitoring, etc. Notably, a wireless underwater monitoring system has been designed, confirming the feasibility of underwater calling for help, further demonstrating the potential applicability of our work in the underwater communication.

Improving the stability of an amperometric ammonia sensor based on BaZr0.8Y0.2O3-δ electrolyte with a volatile B2O3 sintering additive

Yttrium-doped BaZrO3 (BZY) shows great potential as a new solid electrolyte for high-temperature NH3 sensing applications. However, it is difficult to obtain a dense BZY electrolyte due to the refractory nature of this material. For this paper, an amperometric NH3 sensor based on a BaZr0.8Y0.2O3-δ (BZY20) electrolyte was proposed, and volatile B2O3 was added to improve the density of BZY, which was essential to enhance the sensitivity and stability of the sensor. The effects of B2O3 on the density, morphology, and conductivity of the electrolyte were investigated. Furthermore, the influence of the density of BZY20 on the sensitivity and stability of the sensor was analyzed. It was found that the sensitivity and stability were significantly improved by the enhancement of the conductivity. In addition, the sensor could reach a detection limit as low as 2.5 ppm for NH3 at 450 ℃ and showed good selectivity, repeatability, and long-term stability.

Preparation of ultrafast ammonia sensor based on cross-linked ZnO nanorods coated with poly(3-hexylthiophene)

A gas sensing device was fabricated using poly(3-hexylthiophene) (P3HT)-coated ZnO nanorods, and the ammonia (NH3) gas-sensing properties of the heterojunction device were analyzed. Hexagonal ZnO nanorods were prepared using the hydrothermal method on a ZnO seed layer. The ZnO seed layer was deposited using the sputtering method on a Ti–Pt bilayer interdigital electrode. X-ray diffraction and field emission scanning electron microscopy characterized the crystal structure and morphology of the ZnO–P3HT nanorods heterojunction devices. The gas-sensing properties of the P3HT–ZnO nanorods heterojunction sensor were examined and compared with different concentrations of NH3 gas. The response and recovery times were less than 1.5 s with a NH3 gas concentration of 1 ppm. Comparison with sensors of other materials indicated that P3HT was the reason for the short response and recovery times. Plausible mechanisms explaining the enhanced NH3 selectivity of the P3HT–ZnO nanorods heterojunction structure are discussed.

Ammonia sensor detects volatile compounds at room temperatures

The sensor makes it easier to detect the poisonous gas and could be used for industrial, agricultural, and medical applications.

Maltodextrin-overlaid polyvinyl acetate nanofibers for highly sensitive and selective room-temperature ammonia sensors

Various ammonia sensors based on different materials have continuously been developed and employed to enable real-time monitoring of ammonia gas in the environment. Efforts are put not only to improve their sensitivity and selectivity towards the target gas but also to operate them at room temperature. Here, we investigated the effect of overlaying maltodextrin with different concentrations on the surface of polyvinyl acetate (PVAc) nanofibers on ammonia sensing performances, in which quartz crystal microbalance (QCM) was utilized as a transducer to measure the resonance frequency shift affected by the adsorbed gas molecules. Higher concentrations of the overlaying maltodextrin led to larger nanofiber diameter and more functional active groups on the active nanofibrous layers. PVAc nanofibers with 0.05% maltodextrin overlay demonstrated the highest sensitivity of 0.525 Hz·ppm−1 at room temperature, which was 6.4 times higher than their bare counterpart (nanofiber without maltodextrin overlay). That sensor also possessed fast response and recovery times of 32 s and 17 s with a low detection limit (1.92 ppm). Besides its high reproducibility, reversibility, and repeatability, the sensor exhibited outstanding selectivity to other gas analytes and good long-term stability for 32 days of testing. This research shows that maltodextrin overlay can be used as a low-cost alternative route to increase the performance of organic material-based ammonia sensors, especially polymer nanofibers.

Room-temperature flexible ammonia sensor based on SnO2 quantum dots modified graphene oxide

Tin dioxide quantum dots (SnO2 QD) were prepared by hydrothermal method, and then SnO2 QD modified graphene oxide (SnO2 QD@GO) was synthesized by a secondary hydrothermal technique to fabricate a flexible sensor for detecting ammonia at room temperature. The morphology, structure and composition of the composites were analyzed by SEM, TEM, EDS, XPS, XRD and Raman spectroscopy. TEM images showed that SnO2 QD with a diameter range of 5–8 nm present a cuboid structure, embedded in the two-dimensional GO surface. The gas sensing test shows that at room temperature the response of SnO2 QD@GO to ammonia is 5 times higher than that of GO. At the same time, the operating temperature of pure SnO2 QD is greatly reduced from 250 °C to room temperature (24 °C) by the composing of GO. Flexibility test of SnO2 QD@GO was also measured to test the fatigue resistance and bending test of the device. The improved ammonia sensing performance of SnO2 QD@GO is mainly due to the smaller bond energy of ammonia and abundant functional groups of GO, which provides more active sites for the surface adsorption of NH3.

Rapid and sensitive detection of aqueous ammonia harnessing nanocomposite functionalized tilted fiber Bragg grating.

A high sensitive aqueous ammonia sensor based on tilted fiber Bragg grating (TFBG) had been reported. The sensors were fabricated by a 10 ° TFBG coated by a membrane receptor named as Polyaniline/Graphene oxide on the surface of the fiber. The correlative concentrations of aqueous ammonia were demodulated by global monitoring of the envelope area of cladding modes in the transmitted spectrum of the TFBG. Tests have shown that the proposed sensor can provide a linear and rapid response of aqueous ammonia within 22 seconds, in a concentration range from 1-12 ppm. Moreover, the limit of detection can even reach 0.08 ppm, through the theoretical analysis of our experimental results. The proposed sensor has good performance, is easy to manufacture and of small size, making it a good choice for real-time, in-situ, label-free detection of aqueous ammonia in the future.

Cellulose acetate/MOF film-based colorimetric ammonia sensor for non-destructive remote monitoring of meat product spoilage

Herein, we designed an on-site and portable colorimetric assay using cellulose acetate polymeric films incorporated with HKUST-1 metal-organic framework while immersed in a solution of methyl red and brilliant cresyl blue organic dyes as an indicator for monitoring ammonia levels. Ammonia serves as a significant biomarker of food spoilage which falls under the category of volatile organic compounds (VOCs). The designed colorimetric solid-state sensor was comprehensively characterized using FE-SEM, EDS-mapping, XRD, FTIR, and contact angle analyses. The results confirmed the superior stability, water permeability, good crystallinity and desirable morphology of the prepared sensor platform. Additionally, customized smartphone was developed and applied for online signaling and colorimetric analysis. The findings demonstrated two linear ranges: 1–100 ppb and 0.1–1340 ppm with a detection limit of 0.02 ppm. The solid-state sensor exhibited high selectivity in the presence of other VOCs such as methanol, ethanol, acetone, 2-propanol, toluene, humidity, and hexane. It displayed acceptable repeatability in both inter-day (RSD = 3.38 %) and intraday (RSD = 3.86 %), long-term stability over 4 days as well as reusability over 3 cycles. We successfully applied this sensing platform for ammonia monitoring in spoiled meat foods including veal, fish and chicken. The results indicated favorable percentage recovery and repeatability, confirming the feasibility and potential applicability of this intelligent packaging system for monitoring freshness. The platform allows for real-time monitoring and data analysis via smartphone-based online signaling, providing a convenient and effective method for ensuring food quality.

Ammonia and Humidity Sensing by Phthalocyanine-Corrole Complex Heterostructure Devices.

The versatility of metal complexes of corroles has raised interest in the use of these molecules as elements of chemical sensors. The tuning of the macrocycle properties via synthetic modification of the different components of the corrole ring, such as functional groups, the molecular skeleton, and coordinated metal, allows for the creation of a vast library of corrole-based sensors. However, the scarce conductivity of most of the aggregates of corroles limits the development of simple conductometric sensors and requires the use of optical or mass transducers that are rather more cumbersome and less prone to be integrated into microelectronics systems. To compensate for the scarce conductivity, corroles are often used to functionalize the surface of conductive materials such as graphene oxide, carbon nanotubes, or conductive polymers. Alternatively, they can be incorporated into heterojunction devices where they are interfaced with a conductive material such as a phthalocyanine. Herewith, we introduce two heterostructure sensors combining lutetium bisphthalocyanine (LuPc2) with either 5,10,15-tris(pentafluorophenyl) corrolato Cu (1) or 5,10,15-tris(4-methoxyphenyl)corrolato Cu (2). The optical spectra show that after deposition, corroles maintain their original structure. The conductivity of the devices reveals an energy barrier for interfacial charge transport for 1/LuPc2, which is a heterojunction device. On the contrary, only ohmic contacts are observed in the 2/LuPc2 device. These different electrical properties, which result from the different electron-withdrawing or -donating substituents on corrole rings, are also manifested by the opposite response with respect to ammonia (NH3), with 1/LuPc2 behaving as an n-type conductor and 2/LuPC2 behaving as a p-type conductor. Both devices are capable of detecting NH3 down to 10 ppm at room temperature. Furthermore, the sensors show high sensitivity with respect to relative humidity (RH) but with a reversible and fast response in the range of 30-60% RH.

Fabrication and optimization of passive flexible ammonia sensor for aquatic supply chain monitoring based on adaptive parameter adjustment artificial neural network (APA-ANN)

Traditional rigid sensors and imperfect calibration methods are difficult to meet the demand of food quality and safety monitoring in aquatic products supply chain, which requires redesign and optimization. This paper designed and optimized a passive flexible ammonia sensor based on adaptive parameter adjustment artificial neural network (APA-ANN) for aquatic monitoring. The proposed sensor could acquire ammonia information and transmit to the wireless reader by radio frequency identification (RFID) with 13.56 MHz. Through the energy harvesting module, which has a harvesting efficiency of about 63.07%, the passive flexible ammonia sensor could harvest RF energy and supply continuous power for the normal operation of sensor without battery. Oysters and abalone were selected for the sensor output calibration and verification in waterless and watery environments, respectively. The sensor output had a good fitting effect in the sensing range (R2 > 0.99932) and the APA-ANN could improve and optimize the sensor output accuracy under the multiple interference and the impact of cross-sensitivity. The final result showed that all regression coefficients were>0.997 and the accuracy of the optimization model was higher than 89.5%, which proved the applicability of the passive flexible ammonia sensor and provided a optimization method for sustainable monitoring in agriculture.

Analisis Grafik Karakteristik Sensitivitas Sensor MQ-135 untuk Menentukan Persamaan Hubungan antara ppm dan Rs/Ro

MQ-135 sensor is a sensor capable of detecting acetone, toluene, alcohol, carbon dioxide, ammonia, and carbon monoxide. This sensor has been widely used as the main component in gas-based research. Analysis of sensor sensitivity characteristics is the first step for researchers to do to obtain an equation for the relationship between ppm and Rs/Ro. However, in most studies only analyzing gas charts are the object of research. This causes other researchers to do their own analyses for different types of gas. Based on that problem, the authors performed a graphical analysis of the sensitivity characteristics of the MQ-135 sensor for acetone, toluene, alcohol, carbon dioxide, ammonia, and carbon monoxide gases. The coordinate points for these gases are obtained using the WebPlotDigitizer application and coordinate data were analyzed using power regression. Based on the analysis results, the relationship equation between ppm and Rs/Ro for acetone, toluene, alcohol, carbon dioxide, ammonia, and carbon monoxide gas is shown in equations 16, 17, 18, 19, 20, and 21 respectively.

Capacitive, Highly Selective Zeolite-Based Ammonia Sensor for Flue Gas Applications

The selective detection of different gas components will remain of huge importance in the future, either in the ambient air or in flue gases, e.g., for controlling purposes of combustion processes. The focus here is on the development of a highly selective ammonia sensor that will be exemplarily used in the flue gas of biomass combustion plants with catalysts for nitrogen oxide reduction. Such applications require a robust sensor design, in this case, based on a ceramic substrate. The gaseous ammonia is detected with the help of a zeolite film, whose selective adsorption properties towards ammonia are already intensively being used in the field of flue gas catalysis. The adsorption and desorption of ammonia on the gas-sensitive zeolite film lead to changes in the dielectric properties of the functional material. Using an interdigital electrode (IDE) structure below the zeolite film, the capacitance was determined as a measure of the ammonia concentration in the gas. In this context, the fabrication of all layers of the sensor in the thick film with subsequent laser patterning of the IDE structure enables a cost-efficient and effective method. The functionality of this sensor principle was extensively tested during measurements in the laboratory. A high and fast response to ammonia was detected at different sensor temperatures. In addition, very low cross-sensitivities to other gas components such as water (very low) and oxygen (zero) were found.

Dog nose-inspired high-performance ammonia sensor based on biochar/SnO2 composite

Inspired by the ordered tubular structure inside the dog nose and its olfactory receptors, this paper reports a biochar/SnO2 composite based on waste disposable bamboo chopsticks (DBC) combined with tin dioxide (SnO2) nanoparticles. The response of optimized biochar/SnO2 composite reaches 4513 to 500 ppm NH3, and the response/recovery times are 50.4 s and 3.7 s, respectively. The biochar/SnO2 composite displays the dog-nose-like ultra-fast response (1 s response up to 1100) to 500 ppm NH3 at room temperature (25 °C), which makes the biochar/SnO2 composite with the application promising for rapid detection of NH3. The optimized biochar/SnO2 sensor also exhibits good selectivity and linear response with a theoretical detection limit as low as 34 ppb NH3. In addition, the biochar/SnO2 sensor has reliable humidity immunity and long-term stability. Within a period of up to six months, the response fluctuation of biochar/SnO2 sensor to 500 ppm NH3 at 25 °C is less than 3.7%. However, the susceptibility of biochar/SnO2 composite to the operating temperature need to be overcome. The biochar/SnO2 composite was prepared by low-temperature pyrolytic carbonization (300 °C) with the advantages of abundant raw materials, low cost and green environmental protection, providing a new outlet for solid waste.

Open-Path Laser Absorption Sensor for Mobile Measurements of Atmospheric Ammonia.

Anthropogenic emissions of ammonia to the atmosphere, particularly those from agricultural sources, can be damaging to the environment and human health and can drive a need for sensor technologies that can be used to detect and quantify the emissions. Mobile sensing approaches that can be deployed on ground-based or aerial vehicles can provide scalable solutions for high throughput measurements but require relatively compact and low-power sensor systems. This contribution presents an ammonia sensor based on wavelength modulation spectroscopy (WMS) integrated with a Herriott multi-pass cell and a quantum cascade laser (QCL) at 10.33 µm oriented to mobile use. An open-path configuration is used to mitigate sticky-gas effects and achieve high time-response. The final sensor package is relatively small (~20 L), lightweight (~3.5 kg), battery-powered (<30 W) and operates autonomously. Details of the WMS setup and analysis method are presented along with laboratory tests showing sensor accuracy (<~2%) and precision (~4 ppb in 1 s). Initial field deployments on both ground vehicles and a fixed-wing unmanned aerial vehicle (UAV) are also presented.

Graphene/Polyaniline Film Optical Fiber Ammonia Gas Sensor With Excellent Sensing Performance

The possibility to improve the detection index of the optical ammonia gas sensors on the basis of the graphene/polyaniline (graphene/PANI) coated Mach–Zehnder interferometric optical fiber structure with etched thinned core fiber(e-TCF) is investigated. Based on the analysis of the output wavelength, a significant increase in sensitivity and stability of the ammonia sensors is achieved by using TCF. Experimental results show that its sensitivity is -27.8 pm/ppm, the response time is 32 s, dip wavelength error is lower than ±0.02 nm, and the dip intensity error is lower than ±0.002 dB in the stability test. This research illustrates that the proposed sensor has numerous advantages, including small size, strong anti-electromagnetic interference, and excellent repeatability characteristics. Furthermore, it can be applied in biomedical detection applications as it can improve the detection resolution of ammonia concentration at room temperature.

Porous biocompatible colorimetric nanofiber-based sensor for selective ammonia detection on personal wearable protective equipment

Colorimetric sensors are economical and power-free devices for gas detection. Ammonia is used in several industries and overexposure can lead to death. In this study, we demonstrate a simple, single-step fabrication of a sensitive and selective colorimetric ammonia sensor. This sensor is based on simple pH-indicator immobilized electrospun mat and was able to detect ammonia concentrations as low as 0.5 ppm with a fast response time of 10 s. The core-shell bi-polymer nanofiber mat was produced using single nozzle electrospinning with a PDMS shell for selectivity. We overcome the main weakness of colorimetric ammonia sensing which is its response to pH liquids and aerosol by the addition of PDMS shell making it suitable for personal protective equipment (PPE) in industrial environments. The detection range is adjustable by controlling the thickness of the PDMS shell without compromising the other performances of the sensor. Smart PPEs with integrated colorimetric sensors could potentially be used by workers in industrial settings to detect the presence of toxic ammonia gas in a visual way.

Characterization and room temperature ammonia sensing application of hydrothermally synthesized MoS2/RGO nanocomposites

Developing high-performance chemical gas sensor devices based on two-dimensional transition metal dichalcogenides (2D-TMDs) operating at room temperature is still a challenge due to the long and incomplete recovery. In this work, the hydrothermal technique was used to prepare molybdenum disulfide (MoS2)/reduced graphene oxide (RGO) nanocomposites at various amounts of graphene oxide (GO), and its effect on ammonia sensing has been investigated. For this, the weight percentage of GO to ammonium heptamolybdate tetrahydrate changed to 1 (MG1), 3 (MG3), 5 (MG5), and 10 (MG10). Raman analysis showed that the incorporation of GO causes the growth of the 1 T-MoS2 phase in nanocomposite samples. By examining the gas sensing properties of MoS2, RGO, and their nanocomposites, the optimal value of GO in MoS2 for the best performance of the sensor was achieved. The MG10 sample with the highest response (1.41 %), fastest response (58 s), and recovery (176 s) times under exposure to 500 ppm ammonia is the most suitable sensing material for fabricating ammonia sensors among other samples. This sample also showed excellent selectivity to ammonia compared to ethanol, methanol, and acetone. This study presents a new approach to exploit 2D nanocomposites for the detection of ammonia, as a biomarker in the human breath and also an important gas in industry.