Hydrogen Sensors and Switches from Electrodeposited Palladium Mesowire Arrays

TLDR

Hydrogen sensors and switches were fabricated by electrodepositing mesoscopic palladium wires onto graphite surfaces and transferring the arrays onto a cyanoacrylate film. Exposure to hydrogen caused a rapid (<75 ms) reversible drop in resistance that scales with concentration (2–10 %) and is attributed to the closing of nanoscopic gaps in the wires, with fully gapped arrays returning to open circuits when hydrogen is removed.

Abstract

Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires. These palladium "mesowire" arrays were prepared by electrodeposition onto graphite surfaces and were transferred onto a cyanoacrylate film. Exposure to hydrogen gas caused a rapid (less than 75 milliseconds) reversible decrease in the resistance of the array that correlated with the hydrogen concentration over a range from 2 to 10%. The sensor response appears to involve the closing of nanoscopic gaps or "break junctions" in wires caused by the dilation of palladium grains undergoing hydrogen absorption. Wire arrays in which all wires possessed nanoscopic gaps reverted to open circuits in the absence of hydrogen gas.