High-performance BiVO4 photoanodes cocatalyzed with bilayer metal-organic frameworks for photoelectrochemical application.

In this work, we modified a BiVO4 photoanode with bilayer Fe-MOF and Ni-MOF as cocatalysts for the first time and obtained a highly efficient BiVO4 composite photoanode whose photocurrent density was increased by 2.7 times. The optimized BiVO4/Fe-MOF/Ni-MOF photoanode demonstrated a photocurrent density of 1.80 mA/cm2 at 1.23 V vs. a reversible hydrogen electrode (RHE). The onset potential of the BiVO4/Fe-MOF/Ni-MOF photoanode markedly decreased from 0.9 V to 0.69 V in comparison with the pure BiVO4 photoanode. It is speculated that Fe-MOF and Ni-MOF led to more reactive oxygen evolution sites and that the bilayer cocatalysts synergistically promoted the separation of photogenerated electron-hole pairs, which may be the influencing factor for the photoelectrochemical performance of the BiVO4/Fe-MOF/Ni-MOF photoanode being distinctively enhanced. Thus, this work sheds some interesting new light on the construction of a high-efficiency photoanode for photoelectrochemical applications.