Increased Active Sites on Irregular Morphological α-Fe(2)O(3) Nanorods for Enhanced Photoelectrochemical Performance

[Image: see text] Uniform rectangular α-Fe(2)O(3) nanorods (R-Fe(2)O(3)) and irregular α-Fe(2)O(3) nanorods (D-Fe(2)O(3)) with a random size vertically aligned on fluorine-doped tin oxide were prepared with a facile one-step hydrothermal procedure. X-ray diffraction (XRD) measurements and Raman spectra confirm that the obtained samples are α-Fe(2)O(3), and XRD patterns show that D-Fe(2)O(3) has two extra (012) and (104) planes of hematite in addition to the identical peaks to R-Fe(2)O(3). The carrier density of the D-Fe(2)O(3) sample is four times larger than that of R-Fe(2)O(3). Finally, the D-Fe(2)O(3) photoelectrode exhibited a better photoelectrochemical (PEC) performance under visible illumination than that of R-Fe(2)O(3), achieving the photocurrent density of 0.15 mA cm(–2) at 1.23 V versus reversible hydrogen electrode. In addition, incident photo-to-current conversion efficiency of D-Fe(2)O(3) is nearly three times larger than that of R-Fe(2)O(3). Hence, the improved PEC performance of D-Fe(2)O(3) can be ascribed to higher carrier density resulting from the amount of oxygen vacancies and more activated exposed surface facets.