Hydrothermal synthesis of Fe-doped NiO nanoplatelets with enhanced sensing property

Ni(1-x)Fe(x)O (x = 0-0.05) nanoplatelets were synthesized by a facile hydrothermal process. The crystal structure and morphology of the samples were characterized by X-ray diffraction and field emission scanning electron microscopy. The incorporation and the valence state of Fe in NiO nanoplatelets were determined by X-ray photoelectron spectroscopy. Doping NiO nanoplatelets by Fe greatly improves their sensing performance. The Ni0.97Fe0.03O sensor showed the highest response up to 59.5 to 100 ppm ethanol at 280 degrees C, which is a 28.2-fold increase compared to the pure NiO nanoplatelets. The incorporation of Fe3+ into the lattice of NiO results in the decrease of the effective hole concentrations, which plays a key role for the enhancement of the sensing properties. Fe-dopant can be a promising substitute for the noble metal additives to fabricate gas sensors with much lower cost. Finally, the gas sensing mechanism was discussed.