Highly selective and sensitive xylene sensors based on Nb-doped NiO nanosheets

It's demonstrated that doping of aliovalent atom can greatly influence the sensing performance of metal oxides-based gas sensors. In this work, Nb-doped nickel oxides with Nb contents in the range of 6.2-29.1 at% have been synthesized by a one-step hydrothermal method. The gas sensing test results indicates that the 20.2 at% Nb doped NiO possesses an ultrahigh response (335.1-100 ppm), excellent selectivity and theoretical ppb-level detection limit (2 ppb) to xylene at 370 degrees C, which is much better than that of pure NiO sensor. The higher specific surface area and the enhanced catalytic activity caused by higher ratio Ni3+/Ni2+ are considered as the main reasons for the enhanced gas sensor performance.