A highly selective and sensitive HS sensor at low temperatures based on Cr-doped α-FeO nanoparticles.

Cr-doped α-FeO nanoparticles were synthesized by a low-cost and environmentally friendly hydrothermal route. Their gas sensing properties were investigated and the sensor showed high sensitivity and selectivity to HS gas. Different Cr doping levels from 0 to 8.0 wt% were studied, and the sensor of 4.0 wt% Cr-doped α-FeO showed the largest response, with a response of 213 to 50 ppm HS at 100 °C. The incorporation of Cr ions within α-FeO nanocrystals increases the specific surface area, and promotes the oxidation of HS and oxygen adsorption in the air. Thus, the doping of Cr into α-FeO nanostructures would be a promising method for designing and fabricating high performance HS gas sensors.