Electrochemical reconfiguration of NiFe layered double hydroxide on BiVO4 induced by black phosphorus quantum dots for promoting photoelectrochemical water splitting

In this work, black phosphorus quantum dots (BPQDs) and NiFe layered double hydroxide (NiFe-LDHs) were loaded on BiVO4 photoanode for promoting photoelectrochemical (PEC) water splitting. As a narrow bandgap ptype semiconductor with high work function, BPQDs could not only form p-n junction with BiVO4 to enhance light harvest but also construct Schottky junction for charge carriers separation. More importantly, introduction of BPQDs facilitates the transformation of Ni(OH)2 into NiOOH so as to improve the water oxidation capacity at low bias voltage. Density functional theory (DFT) calculation demonstrates that introduction of BPQDs accelerates the alpha/gamma phase transition dynamically and thermodynamically, thus BiVO4/BPQDs/NiFe-LDHs photoanode achieves photocurrent density of 5.28 mA cm-2 at 1.23 V RHE , AM 1.5 G and maintains good stability. In summary, this work provides new ideas for constructing efficient hole extraction layers on photoelectrode, well expanding the application of BPQDs in PEC water splitting.