Patent ID: 8268392

Claim:
A method of forming a visual detector for hydrogen gas by a process comprising the steps of: a) preparing an aqueous mixture of a hydrogen sensitive pigment to form mixture I; b) preparing a stable colloidal solution of metal activator nano-particles by adding a water-soluble protective polymer to an aqueous solution of a metal precursor and reducing the metal precursor with sodium borohydride to form mixture II; c) adding the stable colloidal solution of metal activator nano-particles of mixture II to the aqueous mixture of a hydrogen sensitive pigment (mixture I) to form mixture III; d) soaking a porous substrate in mixture III comprising a stable colloidal solution of metal activator particles and aqueous mixture of hydrogen sensitive pigment; e) removing the soaked porous substrate from mixture III; and f) drying the porous substrate to form a visual hydrogen detector with reversible color change.