摘要 |
A gas sensor element comprising a film of a semiconducting compound of formula I supported by a non-conductive substrate, the film being disposed between conductors for supplying a current to the film and withdrawing a current therefrom. <IMAGE> I in which: M represents 2H, Mn, Fe, Co, Ni, Cu, Hg, Cd, Pb, Pt or Pd; R1 represents H, CH3, Cl, Br, I, CN, CO2H, COOCnH2n+1, CONH2 or NO2; R2 represents H or CH3; and R3a and R3b, which may be identical or different represent H, NO2, Cl, CO2H or CH3; provided that when M represents cobalt at least one of R1, R2, R3a and R3b is other than hydrogen. |