Characterization of H_2Ti_4O_9 with high specific surface area prepared by a delamination/reassembling process

摘要

H_2Ti_4O_9 nanocrystals with high specific surface areas were prepared by delamination and reassembly process through a way of ball milling combined with ion exchange reaction. The samples were characterized by X-ray powder diffraction, transmission electron microscopy, chemical analysis, thermal analysis, N_2 adsorption-desorption isotherm, and absorption spectrum. The crystallites of Ti_4O_9~(2-) in the form of titania nanosheets has lateral size less than 50 nm. The specific surface area of H_2Ti_4O_9 nanocrystals depends on pH value of reassembling solution and ball milling time. H_2Ti_4O_9 nanocrystals prepared by ball-milling of K_2Ti_4O_9 for 2 h and suspending in 1 M HCl followed by precipitation at pH 8 had the specific surface area of 328.4 m~2 g~(-1) which was about 16 times larger than the fibrous H_2Ti_4O_9 prepared by treating original K_2Ti_4O_9 without ball-milling in 1 M HCl.