Pd-loaded SnO2 ultrathin nanorod-assembled hollow microspheres with the significant improvement for toluene detection

- Nanorod-assembled SnO2 hollow spheres were prepared by a one-pot hydrothermal route.
- Nanosized Pd particles decorated on ultrathin SnO2 nanorods for gas detection.
- Sensitization of toluene sensing properties for Pd loading is investigated.
- The mechanism for improved toluene response was described by diffusion pathway.

Pd-loaded SnO2 hollow microspheres have been successfully prepared via a facile one-pot hydrothermal route and subsequent Pd-loaded treatment without involving any templates, surfactants, or capping agents. The morphological and structural characterization confirms that Pd-loaded SnO2 hollow microspheres are hierarchically constructed of numerous well-aligned rodlike SnO2 subunits with ultrathin diameter of about 5-10 nm and monodisperse Pd particles with several nanometers in size. The time-dependent investigation demonstrates that the formation of hierarchical SnO2 hollow spheres is driven by Ostwald-ripening mechanism. Furthermore, gas sensors based on pure and Pd-loaded SnO2 have been fabricated. The Pd-loaded SnO2 hollow microspheres exhibit relatively lower operating temperature, higher response and selectivity to toluene in comparison with that of pure SnO2. Besides structural merits of ultrathin nanorod-assembled hollow and porous structure, the promotion of sensing performances can also be attributed to the contribution of catalytic Pd particles.

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