Hydrogen sensors based on aligned carbon nanotubes in an anodic aluminum oxide template with palladium as a top electrode

Robust carbon nanotube (CNT)-based hydrogen sensors were fabricated from aligned CNTs grown in an anodic aluminum oxide (AAO) template. Without Pd modification, an Au-electrode CNT sensor shows no response to hydrogen gas. On the other hand, a Pd-electrode CNT sensor is sensitive to medium concentration hydrogen gas (from 0.1% to 1.5% H2) at room temperature. The aligned CNTs in the AAO template are also a good support for the nanoporous Pd film sensor, which is sensitive to hydrogen gas at concentrations ranging from 100 ppm to 1.5% H2.