Hydrangea-type bismuth molybdate as a room-temperature smoke and humidity sensor

Detecting smoke at room-temperature using unrealistic metal oxide-based sensor is the most important component in a fire alarm system. We report on highly sensitive and selective chemically grown porous hydrangea-type bismuth molybdate (Bi2MoO6) room-temperature smoke and humidity sensor. The as-synthesized Bi2MoO6 sensor has been initially screened for its structure, morphology, surface elemental composition, type of conductivity and porosity measurements by various means and then is exposed to different gases like ammonia, acetone, ethanol, methanol, and benzaldehyde as a room-temperature i.e., 25 ºC. Hydrangea-type nanocrystalline and mesoporous n-type Bi2MoO6 sensor demonstrates a sensitive response of 59% towards 40 vol% smoke with a fast response/recovery time of 60/14 s at room-temperature which would find a potential use in a fire alarm system. Despite of n-type semiconducting nature, Bi2MoO6 sensor endows quite good response after the exposure of smoke. Effect of smoke concentration and relative humidity on sensor resistance followed performance has also been explored. The alterations in band bending, under various operation conditions, are illustrated using schematic structural views with the help of possible structural images. •Metal oxide nanocomposite.•Eco-friendly, cost effective chemical bath deposition synthesis.•Smoke sensor with high detection ability.•Volatile organic compound.