Controllable synthesis of magnesium oxysulfate nanowires with different morphologies

Abstract

One-dimensional magnesium oxysulfate 5Mg(OH) 2 • MgSO 4 • 3H 2O (abbreviated as 513MOS) with high aspect ratio has attracted much attention because of its distinctive properties from those of the conventional bulk materials. 513MOS nanowires with different morphologies were formed by varying the mixing ways of MgSO 4 • 7H 2O and NH 4OH solutions at room temperature followed by hydrothermal treatment of the slurries at 150 °C for 12 h with or without EDTA. 513MOS nanowires with a length of 20-60 μm and a diameter of 60-300 nm were prepared in the case of double injection (adding MgSO 4 • 7H 2O and NH 4OH solutions simultaneously into water), compared with the 513MOS with a length of 20-30 μm and a diameter of 0.3-1.7 μm in the case of the single injection (adding MgSO 4 • 7H 2O solution into NH 4OH solution). The presence of minor amount of EDTA in the single injection method led to the formation of 513MOS nanowires with a length of 100-200 μm, a diameter of 80-200 nm, and an aspect ratio of up to 1000. The analysis of the experimental results indicated that the hydrothermal solutions with a lower supersaturation were favorable for the preferential growth of 513MOS nanowires along b axis. © 2008 to the authors.