Methane, the primary component of natural gas, is a significant contributor to global warming and climate change It is a harmful greenhouse gas with an impact 28 times greater than carbon dioxide over a 100-year period Preventing methane leakage from transmission pipelines and other oil and gas production activities is a possible solution to reduce methane emissions In order to detect and resolve methane leaks, reliable and cost-effective sensors need to be researched and developed This paper provides a comprehensive review of different types of methane detection sensors, including optical sensors, calorimetric sensors, pyroelectric sensors, semiconducting oxide sensors, and electrochemical sensors The discussed material includes the definitions, mechanisms and recent developments of these sensors A comparison between different methods, highlighting the advantages and disadvantages of each, is also presented to help address future research needs

https://www.mdpi.com/2411-5134/5/3/28/pdf

A Review of Methane Gas Detection Sensors: Recent Developments and Future Perspectives

Co-sputtered Pd/SnO2:NiO heterostructured sensing films for MEMS-based ethanol sensors

Pyrolysis is one of the most efficient and sustainable technologies for converting biomass, solid waste into valuable bioenergy products to achieve future-oriented synthetic energy. As the intelligent automation control has been rapidly developing recently, it is desired to control and adjust the operating parameters in each feedstock reaction stage by accurately measuring the temperatures, pressures, and the produced gas quantity and compositions. This study reviews comprehensively pressure and gas sensors that are applied or potentially applied in pyrolysis. It was found that the operating temperature and reactor pressure are critical parameters affecting the yields and quality of pyrolysis products. Gas sensors can be used to detect various gases and vapors, such as methane, hydrogen, carbon monoxide, and dioxide, to estimate the quality, quantity, and compositions of gas products for their further utilizations during the pyrolysis and upgrading. According to the sensing data of the gas products, operating parameters of the pyrolysis and upgrading processes can be adjusted and optimized to enhance the pyrolysis efficiency and quality of synthetic energy products. As for the performances of available gas sensors, many of them can withstand temperatures up to 1000 °C and have advantages of good selectivity and stable for long-time, which can be utilized for pyrolysis and upgrading processes. The authors' group will develop high temperature wireless SAW gas sensor for monitoring the major gases in the reactor during pyrolysis and upgrading processes and enhance the efficiency of syn-gas production and gas quality via sensing. 

A review of sensor applications towards precise control of pyrolysis of solid waste and biomasses

Gas sensing properties of polypyrrole/poly(N-vinylpyrrolidone) nanorods/nanotubes-coated quartz-crystal microbalance sensor

In a world focused on the development of cybersecurity, many densely populated areas and transportation hubs are still susceptible to terrorist attacks via improvised explosive devices (IEDs). These devices frequently employ a combination of peroxide based explosives as well as nitramines, nitrates, and nitroaromatics. Detection of these explosives can be challenging due to varying chemical composition and the extremely low vapor pressures exhibited by some explosive compounds. No electronic trace detection system currently exists that is capable of continuously monitoring both peroxide based explosives and certain nitrogen based explosives, or their precursors, in the vapor phase. Recently, we developed a thermodynamic sensor that can detect a multitude of explosives in the vapor phase at the parts-per-trillion (ppt) level. The sensors rely on the catalytic decomposition of the explosive and specific oxidation-reduction reactions between the energetic molecule and metal oxide catalyst; i.e. the heat effects associated with catalytic decomposition and redox reactions between the decomposition products and catalyst are measured. Improved sensor response and selectivity were achieved by fabricating free-standing, ultrathin film (1 µm thick) microheater sensors for this purpose. The fabrication method used here relies on the interdiffusion mechanics between a copper (Cu) adhesion layer and the palladium (Pd) microheater sensor. A detailed description of the fabrication process to produce a free-standing 1 µm thick sensor is presented.

/pdf/free-standing-thin-film-sensors-for-the-trace-detection-of-2bzb7iwv8l.pdf

Free-standing, thin-film sensors for the trace detection of explosives.

Tin oxide gas sensor on tin oxide microheater for high-temperature methane sensing

There is an increasing demand for transparent conductors (TCs) in the electronic and optoelectronic industries. In 2 O 3 :Sn (ITO), the conventional TC, is increasingly going up in price, as the In resources diminish. The most favorite alternative to ITO is SnO 2 :F (FTO), which exhibits high thermal and chemical stabilities and use inexpensive raw materials. Here, FTO films are grown on fused silica and soda lime glass sheets through ultrasonic spray pyrolysis (USP) at ~300 °C. The effect of growth temperature on the electrical and optical characteristics of the deposits is studied. Based on the obtained experimental results, origins of the electrical conductivity in FTO are discussed. The developed FTO-coated glasses are utilized as transparent defoggers as an example application. Considering the optimizations performed on the USP method, we now have the know-how to produce FTO films in a pilot plant scale.

Alireza Ranjkesh

Papers

Tin oxide gas sensor on tin oxide microheater for high-temperature methane sensing

SnO2:F Films Grown by Ultrasonic Spray Pyrolysis Suitable for Transparent Defogger Fabrication