Controlled growth of vertically oriented hematite/Pt composite nanorod arrays: Use for photoelectrochemical water splitting

Highly ordered and vertically grown Pt-doped α-Fe₂O ₃ nanorod arrays on a gold substrate were successfully prepared by the electrochemical co-deposition method using an anodized aluminum oxide template. The effect of the Pt doping in α-Fe₂O₃ nanorod arrays on their water splitting ability was investigated for the first time. The elemental maps obtained by energy dispersive spectroscopy showed that the Pt was uniformly dispersed in the α-Fe₂O₃ nanorod arrays. The photoelectrochemical properties of the α-Fe ₂O₃/Pt composite nanorod arrays as a function of the Pt content were studied by measuring their photocurrent-potential behavior in 1M NaOH electrolyte under AM 1.5 100mWcm^-2 illumination. The Pt-doped α-Fe₂O₃ nanorod arrays show an improvement in solar-to-hydrogen conversion efficiency (∼5%) for photoelectrochemical water splitting compared to undoped samples. To the best of our knowledge, it is the highest value yet obtained from α-Fe₂O₃.