Search

Graphical abstract Highlights • Rational assembly of hierarchical SnO 2 hollow cubes with well-aligned ultrathin primary nanorods. • Well-aligned nanorod-assembled cubic structure maintains highly porous and activated surfaces. • Ultrathin primary nanorods and less-agglomerated configuration promote n-butanol sensing characteristics. Abstract A new type of nonspherical hollow nanocubes functionalized with well-aligned rodlike building blocks have been successfully prepared via a facile one-pot hydrothermal approach in case of SnO 2. The structural and morphological characterization reveals that the dense rodlike SnO 2 subunits are vertically distributed on all of the six equivalent facets of cubic structure. The rodlike primary building blocks with a uniform diameter of about 5 nm exhibit a single-crystalline rutile structure. A two-step sequential growth model is proposed based on observation from a time-dependent evolution process, revealing that the initially formed of well-defined ZnSn(OH) 6 solid cubes can serve as sacrifice self-template for the interior hollowing and vertical growth of SnO 2 nanorods. Moreover, gas sensor based on SnO 2 nanocages exhibits the enhanced sensing performances to n-butanol. The significant decrease in response-recovery time can be attributed not only to the interior cavities combined with permeable shells for fast transfer of gas molecules, but also to these high-activated rodlike subunits with ultrathin diameter. [ABSTRACT FROM AUTHOR]

A new type of nonspherical yolk-shell structures in the case of SnO 2 has been successfully prepared by a simple anneal-etching strategy without employing any additional templates or capping agents. The morphological and structural characterization reveals that SnO 2 yolk-shell particles have a hierarchical architecture with penetrable multi-walled surfaces and cuboctahedral shape, where the secondary building blocks are numerous nanoparticles. The synthetic step-dependent evolution process of SnO 2 yolk-shell cuboctahedra is investigated and the possible formation mechanism is also discussed. To demonstrate the merit of unique structure for the fast mass transfer, sensor based on SnO 2 products has been fabricated and the results exhibit excellent sensing performances for toluene detection. It is found that our SnO 2 yolk-shell structures have a response of 28.6–20 ppm toluene at the optimal working temperature of 250 °C, and the response time and recovery time are within 1.8 and 4.1 s, respectively. [ABSTRACT FROM AUTHOR]

The designed preparation of pure and Au-loaded SnO 2 hollow multilayered nanosheets for CO detection has been realized via a rational combination of different purposeful multi-step synthetic route. The synthetic step-dependent shape and structure evolution has been investigated and the formation mechanism for the unique hollow nanosheets is also discussed. The characterized results confirm that flowerlike SnO 2 nanosheets with a polycrystalline rutile structure are assembled from hexagonal mesoporous and multilayered walls, which can further be subdivided into SnO 2 nanoparticles as structural subunits. Furthermore, gas sensors based on the as-prepared pure and Au-loaded SnO 2 have also been fabricated. The Au-loaded SnO 2 hollow nanosheets show significantly lower working temperature, faster response-recovery and improved selectivity to CO in comparison with that of pure SnO 2 . Besides structural merits including hollow and easily penetrated multilayered walls, which facilitate the transport rate and augment the adsorption quantity of gas molecule, the significant improvement of the sensing properties is also attributed to the catalytic effect of Au. [ABSTRACT FROM AUTHOR]