Enhancing the PEC water splitting performance of BiVO4 co-modifying with NiFeOOH and Co-Pi double layer cocatalysts

A new strategy by NiFeOOH and Co-Pi as double layer cocatalysts for modification of BiVO4 to improve the PEC water splitting performance has been proposed. The heterojunction structure formed by BiVO4 and NiFeOOH broadens the light absorption range and accelerates the internal separation of photogenerated carriers, and then quickly captures holes to enter the Co-Pi layer. The holes are efficiently used for the water oxidation on the surface of the photoelectrode through a cyclic catalytic process in the Co-Pi layer. The BiVO4/NiFeOOH/Co-Pi core-shell structure can effectively increase the active surface area and accelerate the interface charge transfer. LSV exhibits excellent photocurrent density (2.03 mA/cm2 at 1.23 V vs. RHE) and lower onset potential (~0.031 V vs. RHE) due to the efficient separation and transfer of photogenerated carriers. The results indicate that the photoelectrode is expected to be used in practical applications. Additionally, the efficiency of the hydrogen and oxygen evolution is improved greatly. This strategy is expected to be applied to other candidate photoanodes for PEC water splitting.