Ultrafine nanoparticles of W-doped SnO 2 for durable H 2 S sensors with fast response and recovery.

Ultrafine nanoparticles of W-doped SnO 2 with an average diameter of 6 nm were fabricated via a facile hydrothermal method. The material shows a reduced particle size and enhanced response to H 2 S gas as compared to the pristine SnO 2 nanoparticles. The detection limit can be down to 100 ppb while the response time and recovery time of the 5%-doped one are reduced to 17 s and 7 s respectively. In addition, the material shows impressive long-term stability of the response through 40 cycles of injection with 10 ppm H 2 S, which is attractive for designing a durable hydrogen sulfide sensor. The doping of W results in the reduction of size and modification of the electronic band structure of SnO 2 , which reduces the response time and recovery time and further improves the sensing durability of the materials.