Photoelectrochemical splitting of natural seawater with α-Fe2O3/WO3 nanorod arrays

Abstract

Solar splitting of seawater is one of the promising ways for large scale utilization of solar energy in the future. Here we reported an efficient and stable photoanode based on earth-abundant materials for photoelectrochemical (PEC) splitting of natural seawater. Through simple hydrothermal growth and deposition-annealing (DA) process, α-Fe2O3/WO3 nanorod arrays were grown on the surface of fluorine-doped tin oxide coated glass. The PEC performance can be optimized simply by varying DA cycles. The photocurrent density reaches about 1 mA/cm2 at 1.23 V vs RHE under the illumination of 100 mW/cm2 (AM 1.5G) which is 2.9 times as that of pure WO3 films and 50 times as that of the pristine Fe2O3 NRs under the same conditions. More importantly, when the materials were used as photoanode for PEC splitting of natural seawater, the performance was kept as well. After 5 h continuous illumination 65% of the initial value of photocurrent density still remained, which imply the good photostability of the materials even at the conditions of PEC splitting of seawater. A possible mechanism for the improved performance of the hybrid photoanode was proposed based on our experimental results.