Synthesis of single crystalline In₂O₃ octahedra for the selective detection of NO₂ and H₂ at trace levels

Abstract

Selective detection of oxidising or reducing species is achieved via selecting operating temperatures and metal loading of single crystalline In2O3 octahedra.

Flexible Gas Sensors Employing Octahedral Indium Oxide Films

“…When operated at the optimal operating temperature of 150 °C, response and recovery times (t90) for nitrogen dioxide were 105 and 785 s, respectively. These are very similar to the values reported in [6]. …”

“…Figure 7 shows the response of the sensors at both temperatures, which is better at 150 °C. S. Roso et al [6] reported an optimum operating temperature of 130 °C for a high-temperature grown In 2 O 3 (octahedral nanoparticles on top of an alumina substrate), which correlates with our results. When operated at the optimal operating temperature of 150 °C, response and recovery times (t90) for nitrogen dioxide were 105 and 785 s, respectively.…”

“…None of the peaks present could be attributed to impurities, confirming the purity of the material synthesized [17]. The results of the XRD analysis for the sample synthesized at 500 °C match those reported previously for In 2 O 3 octahedra synthesized at 1000 °C via the VPT method [6], which indicates that the crystalline quality of the samples discussed in this paper is very similar to the one reported before.…”

“…Sol-gel, chemical vapor deposition, laser ablation, or vapor phase deposition have been employed to grow In 2 O 3 nanomaterials. Recently, we reported the growth of In 2 O 3 nano-octahedra employing vapor-phase transport (VPT) at 1000 °C under an Ar atmosphere [6]. In 2 O 3 octahedra obtained by VPT possess sharp edges and vertices, and were found to be highly sensitive and remarkably selective to NO 2 when operated at moderate temperatures (i.e., 130 °C).…”

Cobalt or Silver Doped WO3 Nanowires Deposited by a Two-Step AACVD for Gas Sensing Applications

“…In order to obtain a gas sensor able to distinguish or being able to discriminate a particular gas from a mixture, a doping material can be introduced to the sensing layer structure to enhance or induce a change in the layer and subsequently obtain either a signal or a higher signal to a target gas. For this purpose, metal-oxide nanoparticles are used as dopant, as it has been demonstrated in our previous works, to perform such labor [1]. As AACVD is a flexible method to grow nanostructures we have successfully designed a 2 step procedure to grow and ensure the loading of dopants to the nanowires with noble metal nanoparticles such as Pt, Au and Pd [2].…”