“…Different nanostructures (nanoparticles, nanotubes, nanocrystals) contribute to the fabrication of gas sensors (Comini 2006;Lupan et al 2010;Sun et al 2012a, b;Moloney and Barrera 2013;Chow et al 2013;Benkstein et al 2014). The main advantage of these sensors is the nanoscopic size of the sensing element and the corresponding nanoscopic size of the material required for a response.…”