Palladium nanocubes decorated on a one-dimensional ZnO nanorods array for use as a hydrogen gas sensor

•Pd nanocubes were synthesized through an inexpensive seed mediated growth process.•ZnO nanorods prepared through a hydrothermal method.•Hybrid Pd/ZnO structure fabricated through a simple drop-casting process.•Feasibility of H2 sensing properties is investigated.•The mechanism for H2 response was described by diffusion pathway.

This study demonstrates the development of a novel structure by synthesizing Pd nanocubes (NCs) decorated on vertical ZnO nanorods (NRs) applied to a resistive-type gas sensor. The shape control of Pd NCs with close {111} packing effects remarkably enhances the catalytic activity and capacity for H2 adsorption compared to that of {100}. The as-prepared structure with high surface-to-volume ratio exhibited robust sensing performance with a strong response of 74% at 100 °C. The speed of the chemisorptions process through diffusion pathway in Pd NCs showed short response and recovery times of about 1.98 and 2.04 min, respectively, towards 10,000 ppm (1%) H2 at 100 °C. Pd NCs expansion at H2 atmosphere were suggested being a dominant factor of the spillover effect that allowed a detection limit as low as 1 ppm at room temperature. In addition, the sensor operating temperature ranged from room temperature to 200 °C.