Enhanced sensor response of Ni-doped SnO2 hollow spheres

A novel sensing material of Ni-doped SnO2 hollow spheres was prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectroscopy and transmission electron microscopy. Gas sensing properties of the sensor fabricated from the as-prepared Ni-doped SnO2 hollow spheres were systematically investigated and compared with those of pristine SnO2 hollow spheres. Results showed that the Ni-doped sensor had a good selectivity to higher alcohols such as n-butanol with much higher response, while the undoped sensor exhibited poor response to all the tested gases with poor selectivity. The enhanced sensor performances are probably attributed to the formation of p–n heterojunctions between p-type NiO and n-type SnO2. It also suggests that the Ni-dopant is a promising substitute for noble metal additives to fabricate sensor materials with a low cost.