Fabrication of a hydrogen sensor using palladium-coated silver dendrites formed electrochemically

Here, we report a cost-effective method for making palladium-coated silver (Ag) dendrites for hydrogen sensing. Ag dendrites, 50–150 nm in diameter, are made through electrochemical migration in a micro-electrochemical cell. They are then coated with a 200-nm-thick palladium (Pd) thin film. The hydrogen sensor made of palladium-coated Ag dendrites showed better hydrogen sensing characteristics than ones made of a pure Pd film. This is due to the large surface area of the Ag dendrites. Heat-treatment made the hydrogen sensing curve more stable, which is attributable to an alloying effect between Pd and Ag.