α-Fe2O3/Ti–Nb–Zr–O composite photoanode for enhanced photoelectrochemical water splitting

Surface modification and doping of titanium dioxide (TiO2) nanotubes are efficient ways to obtain improved photosensitive characteristics. Here we report photocatalytic activity of α-Fe2O3 decorated Ti–Nb–Zr–O nanotube arrays. The Ti–Nb–Zr–O nanotube arrays were fabricated through anodization of Ti–Nb–Zr alloy in electrolytes of 1 M NaH2PO4 containing 0.5 wt% HF. X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the heterojunction nanofilms. Nb- and Zr-doping could enhance the photocatalytic properties of the titanium oxide. However, more Zr-doping could lead to many defects that acted as recombination centers, which reduced the photocatalytic activity of the titanium oxide. The photocurrent density of the Ti–Nb–Zr–O nanotube photoanodes decorated with a small quantity of α-Fe2O3 could exhibit three times as high as that of the undoped TiO2 nanotube photoanodes.