Localized inside-out Ostwald ripening of hybrid double-shelled cages into SnO2 triple-shelled hollow cubes for improved toluene detection
Unique SnO2 triple-shelled hollow cages with a well-defined cubic shape have been successfully prepared via additional deposition of polycrystalline SnO2 on hybrid Zn2SnO4/SnO2 double-shelled nanotemplates followed by removal of Zn2SnO4. Structural characterization demonstrates that SnO2 triple-shelled hollow cubes (THCs) are hierarchically composed of numerous primary nanoparticles with a size of about several nanometers. The synthetic step-dependent multilayered evolution mechanism can be addressed in terms of different hollowing strategies. Based on the unique less-agglomerated multilayered and porous configuration, the gas sensing performances of SnO2 THCs exhibit an obvious improvement of response and shortened response–recovery characteristics at their optimal working temperature, compared with those of referenced single- and double-shelled SnO2 nanostructures.