Wrapping BiVO4 with chlorophyll for greatly improved photoelectrochemical performance and stability

Abstract

Dull surface oxygen evolution reaction (OER) dynamics seriously hinders the application of BiVO 4 (BVO) photoanodes in photoelectron-chemical (PEC) water splitting. In this study, we built an inorganic/organic hybrid photoanode 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 V RHE (RHE: reversible hydrogen electrode), and the onset potential moves 350 mV negatively in 0.5 mol L −1 Na 2 SO 4 . This article provides a general and simple surface hybrid inorganic/organic solution to improve the catalytic ability of photoanodes.

Modulation of charge-transfer behavior via adaptive interface treatment for efficient photoelectrochemical water splitting

“…Among various candidates, BiVO 4 is the most promising candidate for PEC water oxidation because of a low bandgap (2.4 eV), low cost, and ideal band-edge positions. [23][24][25][26] Nevertheless, owing to the severe electron hole recombination and sluggish oxygen evolution reaction (OER) kinetics, the photocurrent densities of BiVO 4 are far below the theoretical value (7.5 mA cm −2 , AM 1.5 G illumination, 100 mW cm −2 ). 27 To further boost large-scale application of this technology, tremendous efforts have been made aiming at improving charge separation and boosting the fast OER kinetics of semiconductor (SC)-based photoelectrodes, such as doping, 28 constructing heterojunctions, 29 plasmonic metal nanoparticle decoration, 30 and electrocatalyst loading.…”

Architecture of a Long-Wavelength Visible–Light–Driven N-Doped WO3/BiVO4 Heterojunction Structure for Highly Efficient Photoelectrochemical Water Splitting

“…However, its photocurrent density must be improved for practical applications. To make a more efficient and reliable material for PEC water splitting, several approaches have been proposed such as heterojunction systems, crystal surface engineering, morphology modulation, cocatalyst engineering, nonmetallic and metal doping, and inorganic/organic hybrid, phase modulation engineering …”