Preparation And Gas Sensing Performance Of The Hierarchical Structure Of Nickel-based Nano Composites

In this work, mesoporous hierarchical architecture were fabricated via a facileone-pot reflux method. The crystal phase of the as-prepared products was characterizedby X-ray powder diffraction (XRD) and FT-IR spectra, respectively. The morphologiesand structures of the composites were carried out using scanning electron microscopy(SEM) and transmission electron microscopy (TEM). The Brunauer-Emmett-Teller(BET) surface area of the products was measured. This work discusses the growingmechanism and gas sensing mechanism of the nanomaterials.Cu doped α-Ni(OH)2which named as NiCu-LDHs nanocomposite. Synthesized bysing nickel nitrate as nickel source, urea (CO(NH2)2) as precipitants, sodium dodecylbenzene sulfonate (SDBS) as surfactant. This work studied the influence of theconcentration of nickel nitrate and the temperature and investigated the sensingperformance of the fabricated samples towards NOxin air at room temperature. Theresult shows that the doping of Cu improve the conductivity of α-Ni(OH)2。The additionof DBS-expand the layer spacing, providing effective and fast channels for fastcapturing and migration of electrons. Gas sensing performance shows that the responseto97ppm NOxof the NiCu-LDHs nanocomposite has a promotion compared pureα-Ni(OH)2. The response of NiCu-LDHs is50%, which for pure α-Ni(OH)2was only29%. The response time of NiCu-LDHs nanocomposite is only8s.Highly mesoporous hierarchical nickel and indium double hydroxide composite(NIDH) have been synthesized via a simple reflux method. NIDH-30compositecontained a lot of oxygen defect sites. The excellent gas sensing performance can beascribed to the synergetic effect of the mesoporous hierarchical structure of thecompsite and the quick electron transfer between the gas molecule and materialsurface.Futhermore, the NIDH-30sensor exhibits excellent sensing properties to NOxdown to ultralow detection limit of9.7ppb at room temperature. The response values ofthe sensors toward97ppm NOxcould reach60%and the response time is only1.2s. In summary, both of the nanocomposites with mesoporous hierarchical structureexhibit excellent gas sensing performance, which also have fast-response to NOxatroom temperature. We believe that this kind of nanomaterials expected to havepromising values in gas sensing field.