NiO-wrapped mesoporous TiO2 microspheres based selective ammonia sensor at room temperature

Pure mesoporous TiO2 microspheres based chemoresistive gas sensors showed response to several organic volatile compounds (VOCs) such as formaldehyde, methanol, ethanol, ammonia and acetone under the UV illumination in the humid air at room temperature. With the loading of NiO at the porous surface of TiO2 microspheres, the sensor indicated a different sensing property. The sensor using 10 wt% NiO-wrapped mesoporous TiO2 composite microspheres showed a good sensitivity to different concentrations of ammonia from 10 ppm to 100 ppm whereas almost no response to other VOCs indicating an excellent selectivity to detect ammonia in the humid air with UV illumination at room temperature.