Co-catalytic effects of Bi-based metal-organic framework on BiVO4 photoanodes for photoelectrochemical water oxidation.

[Display omitted] • Bi-MOF as a co-catalyst is introduced on BiVO 4 surface for PEC water oxidation. • Photocurrent density of the Bi-MOF/BiVO 4 is 2.06 times larger than bare BiVO 4. • Surface charge transfer efficiency of Bi-MOF/BiVO 4 is 1.56 times higher than that of bare BiVO 4. • The co-catalyst of Bi-MOF can efficiently separate photogenerated charges. • Operation stability is also enhanced after Bi-MOF decoration. Metal-organic frameworks (MOFs) are promising co-catalysts for increasingenhancing the performance of photoelectrochemical (PEC) water splitting. In this work, we successfully fabricated an efficient BiVO 4 photoanode for PEC water oxidation by decorating its surface with Bi-based MOF as a co-catalyst via an unconventional immersion process at an ambient temperature. Bi-MOF exhibits a large surface area and promotes bulk charge separation and surface charge transfer in the water oxidation reaction, resulting in an enhancement in the photocurrent density, which is approximately two times larger than that of the bare BiVO 4 photoanode. In addition, the operation stability of our Bi-MOF/BiVO 4 photoanode was dramatically improved, and more than 95% of its initial photocurrent density was retained even after 24 h, indicating that the improved charge transfer by the Bi-MOF layer prohibits the dissolution of the BiVO 4 layer into the solution during the water oxidation reaction. [ABSTRACT FROM AUTHOR]