Physical and photoelectrochemical properties of Zr-doped hematite nanorod arrays

This work examines the effect of Zr⁴⁺ ions on the physical and photoelectrochemical (PEC) properties of hematite (α-Fe₂O ₃) nanorod arrays grown in an aqueous solution containing zirconyl nitrate (ZrO(NO₃)₂) as a dopant precursor. The concentration of ZrO(NO₃)₂ in the precursor solution influenced both the film thickness and the Zr⁴⁺ concentration in the resulting films. Zr doping was found to enhance the photocurrent for water splitting; the highest photocurrent at 1.0 V vs. Ag/AgCl (0.33 mA cm ^-2) for the Zr-doped α-Fe₂O₃ film was approximately 7.2 times higher than that for the undoped film (0.045 mA cm ^-2). Additionally, the incident photon to current efficiency (IPCE) at 360 nm and 1.23 V vs. the reversible hydrogen electrode (RHE) increased from 3.8% to 13.6%. Ultrafast transient absorption spectroscopy suggests that Zr doping may influence PEC performance by reducing the rate of electron-hole recombination.