The selective synthesis of inorganic oxides with unique morphology has attracted considerable interest because of their morphology-dependent properties and applications. 1-3Efforts on most synthetic inorganic oxides have been focused on preparing a stable morphology rather than providing a strategy for producing various morphologies. Therefore, well-controlled methods for synthesizing inorganic oxides with a systematic evolution of morphology should be developed by adjusting the experimental conditions. Among the morphology-controlled syntheses of inorganic oxides, cuprous oxide (Cu 2 O) has been widely investigated due to its ease of preparation.4-8 The morphology-dependent photocatalytic and antibacterial properties of Cu 2 O were also studied recently.9-11 Although Cu 2 O and silver oxide (Ag 2 O) have similar cubic crystal structures, relatively little is known about the morphology-controlled synthesis and physical properties of Ag 2 O.12,13 To date, a study of the morphology-dependent antibacterial effect of Ag 2 O has reported only for different polyhedral shapes including octahedrons, truncated octahedrons, and cubes.14 This study provided a simple precipitation method for the morphological evolution of Ag 2 O from cubes to octapods. Furthermore, the morphology-dependent antibacterial activity of Ag 2 O against E. coli was also examined.Ag 2 O products with various morphologies were prepared from a silver-pyridine (Py) complex solution. Figure 1 shows the X-ray diffraction (XRD) patterns of Ag 2 O prepared using different amounts of AgNO 3 with 1.0/ 40/10 molar ratios of AgNO 3 /pyridine/NaOH, respectively. All peaks corresponded to those reported for bulk Ag 2 O (JCPDS 12-0793, a = 0.4736 nm) with a cubic structure and impurities. Figure 2 shows scanning electron microscopy (SEM) images of Ag 2 O prepared with different amounts of AgNO 3 . At 2.5 mL of AgNO 3 , Ag 2 O formed a regular cubic shape, as shown in Figure 2(a). The mean length of each side was 600 nm. At 5.0 mL of AgNO 3 , Ag 2 O formed a cubic shape, and the mean length of each side was 700 nm. Void spaces were created at the center of the cubic crystal planes, as shown in Figure 2 (b). When the amount of AgNO 3 was increased to 7.5 mL, the void spaces at the center of the cubic crystal planes increased further, as shown in Figure 2(c). As the amount of AgNO 3 was increased up to 20 mL, octapods with eight identical Ag 2 O horns were formed (Figure 2(d)).

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