Synthesis and enhanced gas-sensing properties of ultralong NiO nanowires assembled with NiO nanocrystals

摘要

NiO crystallites based nanowires with different aspect ratios have been synthesized by a hydrothermal reaction of NiCb with NaC_2O_4 and H_2O in the presence of ethylene glycol (EG) and subsequent annealing at 400°C in air. Control over the aspect ratios of NiC_2O_4·2H_2O precursor nanowires in the range of 11-1050 was achieved by adjusting the hydrothermal reaction temperature and time. The formation of the NiC_2O_4·H_2O nanowires results from the selective adsorption of EG molecules on (101), (10 1), (01 0) and (010) prismatic faces of NiC_2O_4·H_2O with a monoclinic structure. The gas-sensing performance of the as-prepared NiO nanowires with different aspect ratios was investigated towards toluene, ethanol, acetone, triethylamine and methanol. It was found that the gas-sensing performance was improved with an increase on the aspect ratios of NiO nanowires.