Hierarchical rh-In2O3 crystals derived from InOOH counterparts and their sensitivity to ammonia gas

Abstract

Constructing novel materials with a hierarchical structure has become an increasingly hot research topic, because the hierarchical structures have wide potential applications in the fields of bionics, electronics, photocatalysis, solar cells, and lithium ion batteries. In this paper, we report on the fabrication of rhombohedral corundum-type indium oxide (rh-In₂O₃) hierarchical rod-aggregates by annealing oxyhydroxide (InOOH) counterparts prepared through a simple solvothermal route without surfactant. The formation mechanism of the InOOH hierarchical structures is suggested. The rh-In₂O₃ hierarchical crystals were tested in the role of sensing ammonia gas, and were found to show an excellent gas-sensitivity to NH₃ as compared to the cubic bixbyite-type indium oxide (c-In₂O₃) analogues.