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

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 BiVO4 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 BiVO4 photoanode. In addition, the operation stability of our Bi-MOF/BiVO4 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 BiVO4 layer into the solution during the water oxidation reaction.