Three-dimensional flower-like Ni9S8/NiAl2O4 nanocomposites composed of ultra-thin porous nanosheets: Fabricated, characterized and ultra-fast NOx gas sensors at room temperature

In this study, the hydrothermal and Chemical Vapor Deposition (CVD) methods were applied to synthesize the Ni9S8/NiAl2O4 (NAS) nanocomposites by in situ using NiAI-LDH (NA) as a template. A series of structural and morphological features show that the NAS 2-1 nanocomposite (NC) with the three-dimensional (3D) flower-like structure which is composed of ultrathin nanosheets (4.1-4.9 nm) and porosity (about 2 nm). The NAS 2-1 (NA:S mass ratio 1:6) NC sensor exhibited the excellent response (20.30) with ultrafast response time (1.06 s) to 100 ppm NOx at room temperature (RT), and the detection limit can reach to 10 ppb, respectively. The superior gas sensitivity of the NAS 2-1 sensor is primarily due to the particular three-dimensional flower-like nanostructures and the synergy between Ni9S8 and NiAl2O4. The NAS 2-1 sensor is expected to be used as a gas sensing material due to its excellent three-dimensional flower-like structure and outstanding properties at RT. (C) 2020 Elsevier B.V. All rights reserved.