Pd-loaded SnO₂ hierarchical nanospheres for a high dynamic range H₂S micro sensor

Herein, a high dynamic range H₂S micro gas sensor was achieved using hierarchical Pd-loaded SnO₂ nanostructures as a sensing material. SnO₂ nanospheres were synthesized using a hydrothermal method without any surfactants or templates, followed by Pd nanoparticle decoration via a facile method. A hierarchical nanostructure of Pd-loaded SnO₂ was formed, and its sensing abilities were compared with those of pure SnO₂ nanosphere-based sensors. The Pd-loaded SnO₂ hierarchical nanostructures showed an ultra-sensitive H₂S detection ability down to 10 ppb, a high dynamic range (4 orders of magnitude) up to 200 ppm, and a low working temperature (150 °C). Thus, this micro gas sensor based on Pd-loaded SnO₂ hierarchical nanostructures has promising applications in universal H₂S detection. The fabrication method presented herein is simple, renewable and operable and thus may be extended to synthesize other types of metal oxide-based semiconductor micro sensors for application in various fields.