Fabrication of ZnxCo1-xO4/BiVO4 photoelectrodes by electrostatic attraction from bimetallic Zn-Co-MOF for PEC activity

Abstract

The metal active sites in photoelectrode materials have an important role for enhancing water splitting reaction in photoelectrochemistry (PEC). In this work, we used the bimetallic Zn-Co-MOF as the template to fabricate ZnxCo1-xO4 metal oxide on the surface of BiVO4 photoelectrode by electrostatic attraction method with exposure more metal active sites. Therefore, the best Zn0.4Co0.6O4/BiVO4 photoelectrodes showed an excellent photocurrent density with about 3.55 mA/cm2 (1.23 V vs RHE, AM 1.5 G) which was about 3 times than the pure BiVO4 photoelectrode (1.18 mA/cm2, 1.23 V vs RHE) and the onset potential was 0.2 V (RHE) which was the lowest for BiVO4-based photoelectrodes. The PEC performance was enhanced can be mainly attributed to the Zn-Co-MOFs derived Zn0.4Co0.6O4 provided more metal active sites on the surface of Zn0.4Co0.6O4/BiVO4 photoelectrodes and efficiently improved the charge separation in the semiconductor-electrolyte interface. Meanwhile, this work used the electrostatic attraction method supplied a simple method for preparing MOFs derived metallic oxide/semiconductor heterojunction nanocomposites.