Background:

As the consequences of poor quality become increasingly known, air pollution has become a significant concern. Quality management in densely populated areas is now strong component of many public health action plans.  To monitor and manage air quality in crowded areas, the development of sensitive and selective environmental gas sensors is critical. Hydrogen sulfide (H₂S) s a life-threatening gas produced from natural sources including sulfate-reducing hydrocarbons and the separation of sour gases.We can use hydrogen sulfide gas sensors for monitoring.

Nanomaterials for gas sensors

Nanomaterials are used as sensing components of sensor devices to improve their effectiveness by allowing higher concentrations of reaction sites because of their high surface-to-volume ratios.

Perovskite materials, such as those with the general formula AMX3, have attracted a lot of research interest in recent years, where "A" represents an inorganic or organic cation, "B" represents a metal cation, usually Pb, and "X" represents a halide anion.

In this study, the researchers employed a hybrid organic perovskite formamidine lead bromide (FAPbBr3, where FA + : CH(NH 2 ) 2+ ), which is a and materials that are highly sensitive to specific gas molecules.

The researchers developed a polycrystalline FAPbBr3 as an H2S gas sensor in which the gas-sensitive component is perovskite particles. The conductivity of the device was altered by the presence of a small amount of H2S gas.

The FAPbBr3 perovskite was fabricated using a solution-based technique. FAPbBr3 nanoparticles were placed on a glass substrate using prefabricated interdigital electrodes. The band-edge absorption at 580 nm of the constructed sensor corresponds to a band gap of 2.13 eV, showing strong sensitivity to light.

The sensitivity and response time of the sensors were tested, and the results showed that they had high sensitivity to H 2 S, as low as 0.5 ppm, and fast response time.

Method

An inverse temperature crystallization (ITC) method was used to generate small millimeter-sized FAPbBr crystals from a 1 M PbBr/FABr solution in DMF:GBL (1:1 v/v)

High-resolution transmission electron microscopy (TEM) is used to create high-quality pictures to evaluate grain size and shape. The FAPbBr3 dispersion was placed on a molybdenum grid and allowed to dry for this purpose. X-ray diffraction (XRD) was performed using an Empyrean XRD diffractometer to determine the composition and crystal structure of FAPbBr3.

The gas response of the devices was evaluated in a Teflon chamber, and each device was mounted on a temperature-adjustable ceramic table with K-type thermocouples monitoring the temperature.

For gas reaction studies, the H 2 S gas was mixed with air using a Bronkhorst mass flow and control device and then injected into the Teflon chamber under seal. The adsorption of H 2 S gas on the nanoparticles changes the charge distribution on their surfaces, resulting in changes in their electrical conductivity.

H2S Gas Detector alarm sensor

The explosion-proof fixed H2S Gas Detector can be used in 24 hours continuous online monitoring of concentrations of Hydrogen Sulfide in the field.The Hydrogen Sulfide gas detector can be used  in refinery, chemical plant, LPG station, boiler room, painting plant and other places with gas exists.

Portable H2S Gas Detector

Portable H2S detector, hydrogen sulfide detector, used for gas storage leakage monitoring, pharmaceutical factory, food factory, hospital gas disinfection residue detection, electrostatic precipitator, gas generator, air purifier, gas leakage, indoor air gas detection site.