Preparation of one-dimensional SnO2–In2O3 nano-heterostructures and their gas-sensing property

Abstract

Herein, we employ a combination of electrospinning and hydrothermal approaches to synthesize 1D SnO₂–In₂O₃ nano-heterostructures with a series of morphological evolutions. Through variations in the mole ratio of Sn⁴⁺ and In³⁺ ions in hydrothermal condition, several 1D SnO₂–In₂O₃ heterogeneous morphologies have been realized. The proposed growth mechanism for 1D nano-heterostructures is expected to be a nucleation-growth process. In₂O₃ nanofibers, as templates, provide numerous nucleation sites for the growth of SnO₂ nanostructures. As the Sn⁴⁺ concentration increases, the SnO₂ nucleus can start to grow from the surface of In₂O₃ template and extend out along the lateral direction until adjacent grains begin to be connected, forming morphological evolutions. The sensor of SnO₂ nanocylinders, grown on In₂O₃ nanofibers (SI-3 sample), exhibits highest response value at optimal operating temperature. The sensor based on SI-3 sample displays quicker recovery capability towards ethanol gas. A rapid recovery rate can be ascribed to the spillover effect and high surface area. The gas-sensing mechanism of 1D SnO₂–In₂O₃ nano-heterostructures has been discussed.