Search

Abstract: Well-defined polyhedral hollow structures (PHSs) Cu2O with hollow interior and high geometrical symmetry are successfully prepared via a novel in situ oxidative etching method at room temperature. X-ray power diffraction (XRD), field-emission scanning electron microscope (FESEM), and high-resolution transmission electron microscopy (HRTEM) techniques were employed to elaborately characterize the structure and morphology of the as-prepared samples. These PHSs Cu2O with hollow interiors and open “window” show effective-applied and good-diffusion structure for the gas-sensing application, which will exhibit short good response, response/recovery times and good reproducibility to ethanol. It is found that type-I nanocages Cu2O have a response of 8.6–50ppm ethanol at the optimal operating temperature of 210°C and the response time is within 23.7s. [Copyright &y& Elsevier]

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]