Highly sensitive hydrogen gas sensors using single-walled carbon nanotubes grafted with Pd nanoparticles

We have investigated the hydrogen gas sensing performance of single-walled carbon nanotubes (SWCNTs) grafted with Pd nanoparticles (NPs). The SWCNTs, modified with dendrimers before grafting, were found to have a much faster response time (3 s) and better recovery but lower response (8.6%) at 10,000 ppm hydrogen gas than those prepared without the dendrimer template (253 s, 25%). This can be ascribed to the dipole moments induced by the dendrimers. Removal of the dendrimers by heat treatment resulted in high response (25%), a fast response time (7 s) at 10,000 ppm hydrogen gas, and an ultra-low concentration H2 detection of 10 ppm at room temperature. In addition, this sample was found to satisfy Sievert's law. Our results demonstrate that SWCNTs grafted with Pd-NPs through a dendrimer-mediated process can be used to fabricate highly sensitive hydrogen gas sensors that exhibit a broad dynamic detection range, fast response times, and excellent recovery.