The present invention provides a delay line SAW device fabricated on a lithium
niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials
such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which
will respond to hydrogen gas in near real time, at low (room) temperature, without
being affected by CO, O2, CH4 and other gases, in air ambient
or controlled ambient, providing sensitivity to low ppm levels.