Ni doped amorphous FeOOH layer as ultrafast hole transfer channel for enhanced PEC performance of BiVO.

Bismuth vanadate (BiVO), as the potential and prospective photocatalyst, has been limited by the issue of poor separation and transfer of charge carrier for photoelectrocatalytic (PEC) water oxidation. Here, a significant increase of surface injection efficiency for BiVO is realized by the rationally designed Ni doped FeOOH (Ni:FeOOH) layer growing on BiVO photoanode (Ni:FeOOH/BiVO), in which doped Ni can induce partial-charge of FeOOH to serve as ultrafast transfer channel for hole transfer and transportation at the semiconductor/electrolyte interface. In addition, the Ni:FeOOH/BiVO shows the η value of 81.6 %, which is 3.28-fold and 1.47-fold of BiVO and FeOOH/BiVO, respectively. The photocurrent density of Ni:FeOOH/BiVO is 4.21 mA cm at 1.23 V vs. RHE, with the onset potential cathodically shifting 237 mV over BiVO and a long-term stability for suppressing surface charge recombination. The UPS and UV-Vis spectra have confirmed the type-II band alignment between Ni:FeOOH and BiVO for promoting carrier transfer. This facile and effective spin-coating method could deposit oxygen evolution catalysts (OECs) availably onto photoanodes with enhanced PEC water splitting.