The invention provides a zero point
self adjustment and calibration method for a catalytic gas sensor. A nano-
semiconductor tin dioxide,
antimony pentoxide and
cerium oxide composite sensitive material is prepared by a chemical
coprecipitation method; the sensitive material is formed by aging,
solid-liquid separation by
centrifugation, deionizing washing,
dehydration by organic solvents,
vacuum drying, and heat treatment; and the sensitive material is prepared into
slurry by glycerin. By coiling technology, a coil with a
diameter of 0.2 mm is coiled by a wire with a
diameter of 0.018 mm, and is suspendedly welded on a standard two-feet socket. The sensitive
slurry is coated on the coil; the coil is heated by ohmic heating to allow the
slurry to be burned into a small ball with certain strength; a shell with holes is sealed on the socket by
capacitor discharge welding; and a gas sensitive element with a
full scale being less than the
volume fraction of 10*10-6v / V for
liquefied petroleum gas (natural liquefied gas,
hydrogen, organic gas) is produced. The gas sensitive element is integrated with the catalytic gas sensor; with the characteristic that the lowest
detection limit of the catalytic gas sensor (a
volume fraction of 50*10-6 v / V) is much higher than the
full scale of the gas sensitive element, when the
detection limit of the gas sensitive element is lower than the
full scale, the concentration of ambient detected gas is considered to be nearly zero, and the zero point of the sensor is adjusted by a one-
chip microcomputer of a conditioning circuit of the catalytic gas sensor; therefore the function of zero point
self adjustment and calibration of the catalytic gas sensor is realized; the invention solves the problem of zero point drift during long-term use of the catalytic gas sensor, realizes the
self adjustment and
calibration function of the self adjustment and calibration, prolongs the alignment calibration period of the self adjustment and calibration.