Nanostructured Fe2TiO5 photoanode with enhanced photoelectrochemical water splitting performance by Zn2+ doping and FeNi(OH)x cocatalyst deposition

Abstract

Fe₂TiO₅ has attracted extensive attention as a promising photoanode for solar water splitting. However, its water splitting performance still needs to be improved. Here, a Zn²⁺-doped Fe₂TiO₅ photoanode decorated with a FeNi(OH)_x cocatalyst was prepared by a two-step electrospray technique, and the photocurrent density of the resultant photoanode significantly increased by a factor of seven at 1.23 V vs. RHE compared to pristine Fe₂TiO₅, while the cathodic shift of the onset potential was up to 250 mV. The obvious improvement on the photoelectrochemical (PEC) performance can be attributed to the cooperative effect of heteroatom doping and cocatalyst deposition. The doping of Zn²⁺ optimizes electron transfer and promotes charge separation efficiency in the bulk of Fe₂TiO₅ films. Meanwhile, the FeNi(OH)_x cocatalyst can accelerate oxygen evolution kinetics and suppress charge recombination at the electrode/electrolyte interface. Thus, combining doping with a cocatalyst by facile electrospray offers an effective strategy for the development of high-performance photoanodes.