【World Express】Breakthrough in High-Temperature Methane Sensors: Russian Scientists Develop Advanced Multilayer Gas Detection Technology

      Researchers at Tomsk State University, in collaboration with Saint Petersburg State University and the Institute for Physics of Microstructures RAS (Nizhniy Novgorod), have developed an innovative high-temperature methane (CH₄) sensor that could revolutionize gas monitoring in extreme conditions. The breakthrough, published in a recent study, demonstrates a novel multilayer thin-film structure capable of detecting methane at temperatures up to 550°C with unprecedented sensitivity and speed.

      The sensor technology, based on a Ga₂O₃/SnO₂/Ga₂O₃ multilayer structure with SiO₂ barrier layers, represents a significant advancement in the field of gas sensing for harsh environments - including thermal power plants, internal combustion engines, and industrial combustion monitoring systems.

Key Achievements:

      -Enhanced methane detection: The sensor achieved a response of 9.46 to 2000 ppm of methane at 550°C, with a remarkably fast response time of just 12 seconds and recovery time of 140 seconds.

      -Significant operation temperature reduction: The addition of a SiO₂ top layer lowered the optimal operating temperature for methane detection by 200°C, making the sensor more energy-efficient while improving performance.

      -Exceptional ammonia sensitivity: The structures demonstrated an impressive response of 40.59 to ammonia at 450°C, with response and recovery times of 10.9 and 64.6 seconds respectively - ranking among the highest reported for metal-oxide-based ammonia sensors.

      -Reduced humidity interference: The SiO₂ top layer effectively minimized the impact of relative humidity on sensor performance, a critical factor for practical applications in variable environmental conditions.

      The research team employed radio frequency magnetron sputtering - a scalable and cost-effective deposition method - to create the multilayer structures. The key innovation lies in the integration of three strategic approaches: formation of polycrystalline β-Ga₂O₃ + SnO₂ mixed-phase thin films, introduction of a SiO₂ diffusion barrier, and deposition of a SiO₂ top layer that acts as a functional filter.

      "The SiO₂ top layer acts as a diffusion barrier that limits the transport of atoms larger than hydrogen in the temperature range of 300-600°C," explains lead researcher A.V. Almaev. "This allows dissociative adsorption of hydrogen-containing molecules on the SiO₂ surface and subsequent diffusion of hydrogen atoms to the underlying sensing layer, significantly enhancing the response to methane and hydrogen."

      The sensors show promise for:

      -Combustion monitoring in industrial facilities

      -Exhaust gas analysis in thermal power plants

      -Internal combustion engine optimization

      -Safety monitoring in extreme environments

      -Air quality control in high-temperature industrial processes

      The sensors demonstrated excellent stability during cyclic exposure tests and maintained consistent performance during long-term testing over 15 days, with only minor variations in response—confirming their suitability for practical industrial applications.

      When compared to existing sensors, the new technology achieves a figure of merit (response/recovery time ratio) of 0.79 s⁻¹ at 550°C, significantly outperforming most reported metal-oxide-based methane sensors operating at similar concentrations. The sensors maintain high performance even at low methane concentrations (100 ppm), making them versatile for various monitoring requirements.

      This research was supported by the Russian Science Foundation (grant number 25-42-10017) and Saint Petersburg State University (project AAAA-A19-119082790069-6).

      The full study is published in Materials Science and Engineering B (doi 10.1016/j.mseb.2026.119622), with detailed characterization of the structural, chemical, and gas-sensing properties of the new sensor technology.