The invention discloses a NiO
nanoparticle gas sensor based on Cr
doping, a preparation method and application thereof. According to the gas sensor element disclosed by the invention, Cr-doped NiO nano-particles are used as a gas sensitive material, the particle size of the Cr-doped NiO nano-particles is 5 to 10 nm, and in terms of atomic percentage, the
doping amount of Cr in the Cr-doped NiO nanoparticles is 0-35%, but not 0, preferably 20-30%, and more preferably 25%. According to the invention, the gas sensor has excellent performance to
benzene series at a low temperature, the lowest detection concentration to
aniline, trimethylbenzene, methylbenzene and
benzyl mercaptan is smaller than 1 ppm, the response value to
benzyl mercaptan at 100 ppb reaches 10.8, ppb-level high-sensitivity detection can be achieved, and the sensor has huge application prospects in the fields of
environmental monitoring, essence manufacturing, preparation of herbicides and insecticides, synthesis of sulphide ore flotation reagents and the like.