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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