Pluronic-assisted modifications of FeOOH precursor facilitate morphology adjustment and performance enhancement of Fe2O3 photoanodes

Morphology regulation and surface modification are crucial strategies to improving the photoelectrochemical water oxidation performance of Fe2O3 photoanodes. In this study, Pluronic F127-assisted synthesis and post-treatment were adopted to achieve surface modification of FeOOH nanorods prepared by hydrothermal technique, thereby adjusting the morphology and surface properties of Fe2O3 photoanodes after calcination. Although the morphology of FeOOH barely changed, the creation of porous nanorods through F127-assisted synthesis and morphological change from worm-like nanorods into nanoplates by F127-assisted post-treatment were realized, and the electrochemically active surface area, crystallinity, number of surface disorders, and photoabsorption property were affected. Furthermore, relatively high intensity of lattice defects and low-valent ferrous ions (Fe2+) were generated after F127-assisted synthesis, and charge transfer from the surface states was increased. Consequently, Fe2O3 photoanode subjected to F127-assisted synthesis exhibited a reduction in the onset potential by 60 mV. The photocurrent density of Fe2O3 increased by 77% at 1.23 V versus reversible hydrogen electrode following a synergistic effect of F127-assisted synthesis and post-treatment.