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Synthesis of uniform porous NiO nanotetrahedra and their excellent gas-sensing performance toward formaldehyde
- Fu, Qingjie, Ai, Mingmei, Duan, Yi, Lu, Lingmei, Tian, Xin, Sun, Dandan, Xu, Yanyan, Sun, Yaqiu
- RSC advances 2017 v.7 no.82 pp. 52312-52320
- X-ray diffraction, annealing, bicarbonates, ethylene glycol, formaldehyde, nanocrystals, nanoparticles, nickel, nickel oxide, porosity, scanning electron microscopy, solvents, surface area, temperature, transmission electron microscopy
- Porous tetrahedron-like NiO nanostructures composed of primary nanoparticles have been successfully synthesized via a facile two-step method for the first time. The tetrahedron-like Ni(HCO₃)₂ precursor was firstly prepared by a solvothermal reaction with the assistance of PVP using a mixture of ethylene glycol and distilled water as the solvent. The porous NiO products were then obtained by annealing the precursor at different temperatures. Some characterization including X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) was performed to obtain structural and morphological information about the as-prepared NiO products. The NiO products obtained by annealing at 400 °C and 500 °C were porous tetrahedron-like particles composed of primary nanoparticles with size increasing with annealing temperature, while the NiO products obtained by annealing at 600 °C were collapsed into irregular nanoparticles. The gas-sensing properties of the three NiO samples were evaluated and the sensors exhibit high sensitivity, good selectivity and stability towards HCHO at 250 °C. The sensitivity of the three samples follows the sample sequence S500 > S400 > S600 due to the combined effect of specific surface area, pore size and defects in the nanocrystals.