Direct Z scheme-fashioned photoanode systems consisting of FeO nanorod arrays and underlying thin SbSe layers toward enhanced photoelectrochemical water splitting performance

An elegant Z-scheme-fashioned photoanode consisting of Fe 2 O 3 nanorod arrays and underlying thin Sb 2 Se 3 layers was rationally constructed. The photocurrent density of the Sb 2 Se 3 -Fe 2 O 3 Z-scheme photoanode reached 3.07 mA cm −2 at 1.23 V vs. RHE, three times higher than that of pristine Fe 2 O 3 at 1.03 mA cm −2 . An obvious cathodic shift of the photocurrent onset potential of about 200 mV was also observed. The transient photovoltage response demonstrates that the suitable band edges ( E CB ∼ −0.4 eV and E VB ∼ 0.8 eV) of Sb 2 Se 3 , match well with Fe 2 O 3 ( E CB ∼ 0.29 eV and E VB ∼ 2.65 eV), permitting the photoexcited electrons on the conduction band of the Fe 2 O 3 to transfer to the valence band of Sb 2 Se 3 , and recombine with the holes therein, thus allowing a high concentration of holes to collect in the Fe 2 O 3 for water oxidation. The transient absorption spectra further corroborate that the built-in electric field in the p-n heterojunction leads to a more effective separation and a longer lifetime of the charge carriers. An elegant Z-scheme-fashioned photoanode consisting of Fe 2 O 3 nanorod arrays and underlying thin Sb 2 Se 3 layers was rationally constructed.