One-step synthesis of mesoporous Al₂O₃–In₂O₃nanofibres with remarkable gas-sensing performance to NO_xat room temperature

Abstract

The mesoporous Al2O3–In2O3 composites with one-dimensional (1D) nanofibres (NFs) have been fabricated via a facile one-step synthesis of the electrospinning approach, followed by appropriate thermal treatment under ambient conditions. The composite nanomaterials display high dispersion of both In2O3 and Al2O3, forming a heterostructure and mesoporous tubular structure in a broad Al : In atomic ratio up to 1 : 4. It has been found that the Al2O3 composite tube-like nanostructures not only increase efficient sites for gas adsorption, but also possess higher donor densities. Moreover, the mesoporous structure also provides effective and fast channels for fast capturing and migration of electrons. The results show that the mesoporous Al2O3–In2O3 nanotubes exhibit excellent sensing properties to NOx down to a detection limit of 291 ppb at room temperature (RT), while containing 20 at% Al2O3 (labeled as meso-20AI NTs) with an average diameter of nanoparticles of about 10 nm. With respect to the 97 ppm NOx, the maximum response of 100 was determined, 7.3 times as high as the pure In2O3 NTs. Owing to its unique composite structure, 1D meso-20AI NTs may be promising for application in gas sensors.