Stable catalysts for electroless metallization

A method comprising:

• a) providing a substrate;
• b) applying an aqueous catalyst solution to the substrate, the aqueous catalyst solution comprises nanoparticles of one or more metal chosen from silver, gold, platinum, palladium, iridium, copper, aluminum, cobalt, nickel and iron, and one or more stabilizing compounds chosen from gallic acid, gallic acid derivatives and salts thereof, the aqueous catalyst solution is free of tin;
• and
• c) electrolessly depositing metal onto the substrate using an electroless metal plating bath.