Pd nanowire sensors for hydrogen detection

A very sensitive hydrogen sensor is fabricated using palladium (Pd) nanowires electroplated using anodized alumina template. The mechanism for detecting hydrogen concentration is different from conventional hydrogen sensors using Pd. The Pd nanowires have a diameter of about 80 nm and the spacing between the wires is about 10 nm. In a diluted hydrogen environment, the wires become swollen as a result of hydrogen dissolution and as a result the resistance decreases due to the closer gap between the wires. Even though a Pd nanowire sensor has been reported by the Penner group (2001), the sensor has a different sensing mechanism and structure of joining nanocrystallites being composed of Pd nanowires and the lower limit of hydrogen concentration is about 1%. The sensor fabricated in this study shows faster response time and can detect as low as 0.1% hydrogen concentration.