Synthesis of alumina nanofibers by a mercury-mediated method

Alumina nanofibers were successfully synthesized in mercury media at room temperature. Structure and morphology of the nanofibers were characterized by TEM, EDX, FESEM, XRD, TG, DTA and N2 adsorption–desorption. The results show that the as-grown alumina nanofibers are amorphous, and have diameters of 5–15 nm and lengths up to several micrometers. After calcinated at 850 °C for 2 h, the amorphous alumina nanofibers convert to γ-Al2O3 nanofibers. The mechanism for the growth of alumina nanofibers was discussed and a model representing the growth process was presented. During the process, mercury will be produced by metathesis reaction of HgCl2 and Al, Al atoms continuously dissolve into mercury and diffuse to amalgam/air interface, and then Al atoms react with oxygen and water in air, finally alumina nanofibers can be formed.