Fast response of hydrogen sensor using palladium nanocube-TiO2 nanofiber composites

In this work, we investigated the properties of resistivity type hydrogen (H2) sensor for monitoring in H2 gas. The H2 sensor was made of Pd nanocube (NCs) and TiO2 nanofiber (NFs) composites. The Pd NCs was synthesized by seed-mediated growth and TiO2 nanofiber was synthesized via electrospinning method. The two nanomaterials are then converted into nanocomposites by ultrasonication process. Pd NCs-TiO2 NFs composite was characterized by scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM). The H2 sensing properties including the response/recovery time, the response value and linearity of the synthesized samples were investigated toward to various H2 concentrations (0.6, 0.8 and 1%). The response of H2 sensor is S = 40.8% and the response/recovery time are 25/1 s with 0.6% at working temperature of 150 °C. Moreover, the H2 sensor has excellent cross-selectivity for H2 compared to ethanol, nitrogen dioxide and isopropyl alcohol.