Boosting the performance of hematite photoanodes for solar water oxidation by synergistic W-incorporation and Zr-passivation

Abstract Incorporating impurities into hematite is an effective approach to enhance the photoelectrochemical (PEC) water splitting performance of hematite photoanode. Here, we report an efficient W-incorporation in hematite (W-Fe 2 O 3 ) to enhance the PEC performance by depositing a WO 3 underlayer onto the FTO substrate. The W-incorporation dramatically enhances the photocurrent density of hematite by a factor of ∼2. Moreover, it can be well coupled with Zr to achieve a high photocurrent of 2.0 mA cm −2 at 1.23 V vs . RHE by simultaneously depositing a ZrO 2 underlayer on the FTO substrate. A large cathodic shift of the onset potential up to 120 mV can also be obtained. The boosted PEC performance can be attributed to the synergistic effect of W and Zr in hematite, which can both improve the carrier density (by W-incorporation) and suppress the charge recombination (by Zr-passivation).