Facile synthesis of SnO2 nanocrystalline tubes by electrospinning and their fast response and high sensitivity to NOx at room temperature

Abstract

A novel SnO₂ material with tube-like structure has been fabricated through an efficient and facile approach of electrospinning, with subsequent appropriate thermal treatment in atmosphere. The tin dioxide nanocrystalline tubes (TONTs) predominantly consist of 5–10 nm SnO₂ nanoparticles. By using NO_x as a probe molecule, the TONTs exhibit excellent sensing performances in terms of high response, fast response–recovery and good stability at room temperature. The outstanding performance in gas sensing of TONTs arises from (i) their one-dimensional hollow nanostructures with two adsorbed layers on both the outer and inner surfaces, overlapping and connecting nanocrystallites with four or more adjacent grains through necks, (ii) a large number of sensing active sites (chemisorbed oxygen: O⁻, O²⁻, O₂²⁻), and (iii) preferential orientation of the (101) crystal face. The possible gas sensing mechanism of the TONTs is explained by a model in which the effect of NO_x adsorption on SnO₂ nanoparticles and electronic transport properties are discussed based on DFT analysis and experimental results. The annealed TONTs show excellent sensing characteristics to NO_x even at <10 ppb.