The synergistic effect of CuBi2O4 and Co-Pi: improving the PEC activity of BiVO4-based composite materials

Abstract

Reducing the reaction barrier on the photoelectrode surface and increasing the water oxidation power of the sample surface are the key issues to improve photoelectrochemical water splitting performances. In this study, a new BiVO₄/CuBi₂O₄/Co-Pi photoanode has been prepared. CuBi₂O₄ and BiVO₄ form a heterojunction structure that widens the absorption range of light and accelerates the separation of photogenerated carriers in the photoanode, thereby allowing holes into the next layer (cocatalyst layer) faster. The Co-Pi constituent acts as a water oxidation catalyst that can accelerate the interface charge transfer and increase the active surface area. Linear sweep voltammetry is used to determine the photocurrent density of BiVO₄/CuBi₂O₄/Co-Pi, being 1.88 and 1.23 times bigger than that of BiVO₄ and BiVO₄/CuBi₂O₄, respectively. In addition to this, the BiVO₄/CuBi₂O₄/Co-Pi photoanode creates a synergy effect that leads to a wider range of light absorption, higher carrier separation efficiency, and greater water oxidation power so the hydrogen evolution and oxygen evolution rates after recombination increased by 5.68 times and 5.66 times. The results prove that ternary semiconductor structures can improve photoelectrochemical performance. The strategy has great potential in the development of photoelectrochemical water splitting.