Mössbauer effect study of the Β-FeOOH to α-Fe2O3 phase transformation

Effect of HCl additions on forced hydrolysis of FeCl3 solutions

“…a-FeOOH at pH 1-2 proceeded by way of the dissolution/reprecipitation mechanism, and the precipitation process was promoted by adding seed crystals. Knese et al [26] used Mössbauer spectroscopy to investigate the transformation of h-FeOOH to a-Fe 2 O 3 in the suspension at pH 8.5 and 100 jC. a-FeOOH was found as intermediate phase, and it was supposed that the formation of a-Fe 2 O 3 can proceed by way of (a) direct transforma- Fig.…”

Formation of porous α-Fe2O3 microstructure by thermal decomposition of Fe(IO3)3

“…␣-Fe 2 O 3 as a single phase was found at 600 • C; however, it was contaminated with residual sulfate groups. Knese et al [4] used Mössbauer spectroscopy to monitor ␤-FeOOH → ␣-Fe 2 O 3 transition. Brown et al [5][6][7] prepared a sulfated ␣-Fe 2 O 3 from ␣-FeOOH with adsorbed SO 4 2− anions; these authors also investigated the effect of sulfation on ␣-Fe 2 O 3 catalyst for methane oxidation.…”

“…Knese et al [4] used Mössbauer spectroscopy to monitor ␤-FeOOH → ␣-Fe 2 O 3 transition. Brown et al [5][6][7] prepared a sulfated ␣-Fe 2 O 3 from ␣-FeOOH with adsorbed SO 4 2− anions; these authors also investigated the effect of sulfation on ␣-Fe 2 O 3 catalyst for methane oxidation. Baker et al [8] showed that the sulfation procedure is responsible for the generation of axial mesoporous voids along acicular ␣-Fe 2 O 3 crystallites.…”