Al2O3(M = Pt, Ru) catalytic membranes for selective semiconductor gas sensors

Semiconductor gas sensor stability and selectivity can be improved by using catalytic filtering membranes to avoid the gas interference. The filtering membranes of pure and Pt or Ru doped Al2O3 with various thickness (9–53 nm) were deposited on the surface of SnO2(Pd) films by aerosol pyrolysis method. Phase composition and microstructure of the films were studied by XRD, AFM and EPMA. s properties of SnO2(Pd)/Al2O3 and SnO2(Pd)/Al2O3(M) structures (M = Pt, Ru) were studied under H2, CH4 and CO–air gas mixtures at 100–300 °C. All membranes reduce significantly sensitivity to CO and increase the sensitivity to CH4 at 200 °C. Ru-doped membranes significantly reduces the sensitivity to H2. The sensitivity and response time considerably depend on membrane thickness.