A Superior Sensor Consisting of Porous, Pd Nanoparticle–Decorated SnO2 Nanotubes for the Detection of ppb-level Hydrogen Gas

• Pd decorated porous SnO 2 nanotubes are synthesized. • Ppb-scale H 2 gas sensing performances are analyzed. • Effect of structure of the nanomaterials in H 2 sensing is analyzed. • Enhanced sensing mechanisms of the sensor are discussed. Pd nanoparticle–decorated SnO 2 nanotubes (Pd/SnO 2 NTs) are synthesized in this study by electrospinning (using a coaxial spinneret) for application as a hydrogen gas sensor. The inner and outer diameters of the porous, polycrystalline Pd/SnO 2 NTs are 80 nm and 120 nm, respectively, and the Pd nanoparticles decorating the Pd/SnO 2 NTs are comparatively small with an average diameter of 5 nm. The catalytic effect of the Pd nanoparticles and the large effective surface area of the Pd/SnO 2 NTs enhance the performance of a resulting sensor. Furthermore, owing to the hollow, porous, polycrystalline structures of the SnO 2 nanotubes, Pd nanoparticles decorate with high loading and uniform distribution of each constituent grain, maximizing their catalytic effect. As a result, the sensing response of a Pd/SnO 2 NT sensor to 10 ppm hydrogen gas of 54.43 is 4.3 times higher than that of a SnO 2 NT sensor of 12.69.