Porous silicon/α-MoO3 nanohybrid based fast and highly sensitive CO2 gas sensors

We report a high-performance CO2 gas sensor developed from porous silicon/molybdenum trioxide nanohybrid structure (p-Si/MoO3) synthesized via a simple vacuum thermal evaporation over an electrochemically fabricated microporous silicon substrate. The crystal structure, morphologies, and elemental composition of the proposed gas sensor were analyzed using, X-ray diffraction, Field emission scanning electron microscopy, Transmission electron microscopy, and X-ray photoelectron spectroscopy techniques, respectively. The p-Si/MoO3 nanohybrid sensor exhibited an excellent sensing performance towards CO2 gas with high sensitivity (15% at 150 ppm CO2), good repeatability along with fast response time (8 s at 100 ppm CO2) at 250 °C, which makes it promising for practical CO2 sensing applications. Additionally, the sensor presented a low working temperature of 150 °C along with a lower detection limit of 50 ppm CO2. •Fast responsive CO2 gas sensor using porous silicon/molybdenum trioxide nano-hybrid system.•Molybdenum trioxide (MoO3) nanorods deposited on the porous silicon substrate by physical vacuum evaporation, method.•Sensor fabricated on porous silicon (p-Si/ MoO3) responded 20% faster than crystalline silicon substrate.•Lowest response time observed was 8 s for p-Si/MoO3 sensor working at 250 °C for 100 ppm of CO2 gas.