XRD patterns (a) and SEM images (b-h) of the hydrothermal products. The products were synthesized at different temperatures for 12.0 h, with the molar ratio of FeCl3/H3BO3/NaOH = 2:3:4. Temperature (°C) = 90 (a1, b), 105 (a2, c), 120 (a3, d), 150 (a4, e, f), 180 (a5, g), 210 (a6, h). Inset: high-resolution SEM image (c1) as well as the longitudinal length distributions (d1, g1, h1) of the corresponding samples. The asterisk represents hematite (α-Fe2O3, JCPDS No. 33–0664); nabla represents akaganeite (β-FeOOH, JCPDS No. 34–1266).
Zhu et al. Nanoscale Research Letters 2013 8:2 doi:10.1186/1556-276X-8-2