Patent ID: 8003055

Claim:
A composition of matter for variable or tunable visual detection of hydrogen gas in a confined environment, consisting of: a) a hydrogen sensitive pigment selected from at least one of oxides, hydroxides, hydrated oxides, acids, oxysalts and polyoxometalates of tungsten, molybdenum, vanadium, chromium and a combination thereof; b) a plurality of metal activator nanoparticles that is a noble metal selected from at least one of platinum, palladium, rhodium and iridium; and c) a non-layered substrate selected from at least one of a fibrous structure and a woven structure wherein the hydrogen sensitive pigment and the metal activator nanoparticles penetrate the substrate material and in combination form a visual hydrogen gas detector with variable reversible color change, wherein coloration occurs in the presence of hydrogen gas and bleaching occurs in the absence of hydrogen gas and color change is observed from both sides of the substrate.