Boosting room temperature response of Pd-based hydrogen sensor by constructing in situ nanoparticles

Palladium-based H2 sensors have attracted increased attention due to the high selectivity for H2, yet evident limitations like hydrogen embrittlement and slow response rates, have impeded the further development. Aiming to address these issues, adding other metals to form Pd-based alloys and optimize coincided surface structure, are widely considered as effective approaches. Here in this work, Pd/Ti alloy films with proper elemental ratios were prepared by using a magnetron co-sputtering technique, and the coincided sensing features have been further regulated by in situ nanostructuring. For the Pd/Ti film with an atomic ratio of 74.1/25.9, the H2 response values characterizations revealed that the limit of detection (LoD) could be 50 ppm at room temperature, combined with a response time of 61.3 s at 2 vt.% H2 concentration. Based on the first-principles calculations, the effects from hydrogen diffusion process of Pd and Pd/Ti alloys have been evaluated to be ignorable, however, the specific nanostructures constructed on the surface then become the main reason for the boosted response performance. More importantly, the approach of forming proper in situ nanoparticles has been identified as a significant guidance, for extensive and rapid response of H2 detection of Pd-based sensors used upon low power consumption.