Wrapping BiVO4 with chlorophyll for greatly improved photoelectrochemical performance and stability

Abstract

Dull surface oxygen evolution reaction (OER) dynamics seriously hinders the application of BiVO4 (BVO) photoanodes in photoelectron-chemical (PEC) water splitting. In this study, we built an inorganic/organic hybrid photo-anode to improve the PEC performance of BVO by covering a multifunctional film. The film contains modified chlorophyll (Chl) organic compounds and Co and Si ions with a gradient distribution. The Co ions present at the interface between BVO and Chl promote the transport of photogenerated holes, and the Si ions on the surface of the photoanode enhance the hydrophilicity of PEC cells. This modified Chl film not only reduces the OER barrier and promotes carrier transfer but also inhibits loss of vanadium and increases the stability of the BVO photoanode. Finally, the modified BVO photoanode exhibits a photocurrent density of 5.1 mA cm−2 at 1.23 VRHE (RHE: reversible hydrogen electrode), and the onset potential moves 350 mV negatively in 0.5 mol L−1 Na2SO4. This article provides a general and simple surface hybrid inorganic/organic solution to improve the catalytic ability of photoanodes.