One-Step Hydrothermal Synthesis of High-Performance Gas-Sensing Crystals CdIn₂O₄ with Octahedral Shape

Abstract

Octahedrally shaped CdIn₂O₄ was synthesized in a one-step hydrothermal reaction without any surfactant. These octahedral particles used as an ethanol sensor revealed excellent gas response, which is comparable to the well-known SnO₂-based gas sensors. The octahedral CdIn₂O₄ powder possesses the active {111} facets, which contribute to the higher gas-sensing performance of octahedral CdIn₂O₄ than that of the nanosized CdIn₂O₄ powder obtained by coprecipitation method. The XPS results demonstrated that the CdIn₂O₄ octahedra enclosed by {111} facets provided more oxygen vacancies, resulting in the enhanced performance. The calculation also showed higher surface energies for the {111} orientation, which confirms the mechanism of the enhanced gas-sensing performance of the octahedral particles. The as-formed crystals with controlled morphology provide insights for the designed strategy of high-performance gas-sensing materials, and this synthetic route provides flexibility and selectivity for the deliberate preparation of other functional materials