Well-aligned Nd-doped SnO₂ nanorod layered arrays: preparation, characterization and enhanced alcohol-gas sensing performance

Abstract

Well-oriented neodymium doped SnO2 layered nanorod arrays were synthesized by a substrate-free hydrothermal route using sodium stannate and sodium hydroxide at 210 °C. The morphology and phase structure of the Nd-doped SnO2 nanoarrays were investigated by X-ray powder diffraction spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman scattering spectroscopy, X-ray photoelectron spectroscopy and the BET method. The results demonstrated that the Nd-doped SnO2 layered nanorod arrays showed a unique nanostructure combined together with double layered arrays of nanorods with a diameter of 12 nm and a length of several hundred nanometers. The Nd-doped layered SnO2 nanoarrays kept the crystal structure of the bulk SnO2 and possessed more surface defects caused by the Nd ions doped into the SnO2 lattice. The Nd dopant acts as a crystallite growth inhibitor to prevent the growth of SnO2 nanorods. An investigation into the gas-sensing properties indicated that the optimized doping level of 3.0 at% Nd-doped SnO2 layered nanorod arrays exhibited an excellent sensing response toward alcohol at a lower temperature of 260 °C. The enhanced sensor performance was attributed to the higher specific surface area, multi-defect surface structure and the excellent catalytic properties of Nd dopant that is able to increase the amount of active sites on the surface of semiconducting oxides. The Nd-doped SnO2 nanoarray sensors were considered to be a promising candidate for trace alcohol detections in environmental gas monitoring.

Diverse Adsorption/Desorption Abilities Originating from the Nanostructural Morphology of VOC Gas Sensing Devices Based on Molybdenum Trioxide Nanorod Arrays

“…In this experiment, the MoO 3 nanorods showed almost the same molecule-surface bonding force, but the bulk MoO 3 , such as the dense seed layer, might possess a different molecule-surface bonding force because the surface potential energy of nanorods may higher than that of the bulk layer, [47] as seen in Figure S3 (Supporting Information). Because the lower surface potential energy results in a stronger bonding force between the oxide surface and gas molecules, the desorption ability will be weak when exposed to the oxygen gas during the recovery process, which suggests that recovery time may be delayed in the dense seed layer compared with that of the nanorods.…”

Physical properties of neodymium tin oxide pyrochlore ceramics

“…It is also worth noting that the increase in α value is highly pronounced in the 1.1 eV to 2.2 eV and 3.7 eV to 5.13 eV regions. The plot of the (αE) 2 vs. E reflects one region of variation that permitted determining the direct allowed transitions energy band gap E g of the neodymium tin oxide pyrochlore in accordance with the equation:…”

“…These nanorods were found to exhibit * E-mail: atef.qasrawi@atilim.edu.tr excellent features for alcohol gas sensing. It was suggested that the Nd-doped SnO 2 nanoarray sensors can be regarded as a promising candidate for detection of alcohol traces in environmental gas monitoring [2]. In addition, high responsivity of neodymium tin oxide pyrochlore to ion irradiation designates it as a promising material for disposal of nuclear waste [3].…”

Synthesis of highly sensitive disordered porous SnO2 aerogel composite material by the chemical deposition method: synergistic effect of a layer of CuO thin film

“…Mishra et al 9 described Cudoped SnO 2 nanoparticles, which were synthesized by a coprecipitation method, and were then investigated as a formaldehyde sensing material. The 1.5 wt% Cu-doped SnO 2 showed a selective high response ($80%) to 50 ppm concentration of formaldehyde at 200 C. Qin et al 15 prepared Nd-doped SnO 2 nanorods by a substrate-free hydrothermal route of using sodium stannate and sodium hydroxide at 210 C. The Nddoped SnO 2 nanorods with an optimized Nd doping level of 3.0 wt% exhibited an excellent sensing response toward alcohol at 260 C. Li et al 2 demonstrated Cu 2+ /Au co-doped SnO 2 nanobers by electrospinning method, which were used to detect acetylene (C 2 H 2 ) at 160 C.…”

“…14 The sensing properties of a gas sensor are greatly inuenced by the microstructures, grain size, morphologies, and temperature. 15,16 SnO 2 materials have been prepared with different structures, 17 such as nanotubes, 18 nanorods, 19 nanosheets, 20 nanobers, 21 hollow spheres, 22 hierarchical owerlike nanostructures, 23 hollow porous microcubes, etc. [24][25][26][27][28] With the deepening of the research, it is found that the gas sensing properties of the SnO 2 -based composite materials are much higher than those of pure SnO 2 .…”