La and Fe co-doped walnut-like cubic-rhombohedral-In2O3 for highly sensitive and selective detection of acetone vapor

Abstract

Cubic-rhombohedral-In2−2xLaxFexO3 (x = 0, 0.03, and 0.05) composites were prepared by a hydrothermal method. XRD and SEM reveal that pristine cubic-rhombohedral-In2O3 composite mainly consisted of In2O3 nanoparticles in the cubic phase, while introducing appropriate amount of La and Fe ions (x = 0.03 and 0.05) promoted the growth of rhombohedral-In2O3 nanosheets, which constituted the backbones of fuzzy walnut-like hierarchical structure. BET and XPS show that the La and Fe co-doped cubic-rhombohedral-In2O3 composites are higher in the BET surface area and the relative contents of surface In+ ions and OV. From the reception and conduction mechanisms, the highly sensitive and selective detection of acetone by In1.90La0.05Fe0.05O3 is attributed to the fuzzy walnut-like hierarchical structure with enhanced surface reactivity and efficient heterojunction between cubic-In2O3 and rhombohedral-In2O3.