Direct conversion of single‐layer SnO nanoplates to multi‐layer SnO2 nanoplates is achieved by annealing in an O2 ambient at 700 °C. For 50 ppm ethanol, the sensitivities of the multi‐layer SnO2 nanoplates are more than double that of single‐layer SnO2 nanoplates, which are also formed from the single‐layer SnO. The higher sensitivity of the multi‐layer nanoplates is attributed to their larger surface/volume ratio. The facile fabrication of interconnected multi‐layer SnO2 nanoplates at low temperature directly on a Si substrate and sensing chip without the aid of catalysts offers vast advantages over competing methods for the fabrication of high‐sensitivity SnO2 sensors.

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Hexagonal ringlike superstructures (HRLSs) composed of hexagonal single-crystal Co-doped ZnO nanorods were synthesized via a combined hydrothermal and electrochemical process. The unique HRLSs are based on the oriented attachment of single-crystalline Co-doped ZnO nanorods of hexagonal shape driven by the electric dipole interactions of nanorods. The cathodoluminescence (CL) peaks show redshifts of about 30 and 57 nm from the band gap edge emission of the pure ZnO nanorods for 0.25 and 1% Co-doped ZnO nanostructures, respectively. Furthermore, high-temperature ferromagnetism was observed in both 0.25 and 1% Co-doped ZnO nanostructures at 350 K. The brand new member of the family of ZnO nanostructures may serve as a useful component for optical and magnetic applications in nanodevices.