Heterointerface-induced unsaturated coordinated oxygen centers of Cu2V2O7 enable efficient photoelectrocatalytic water oxidation

Abstract

Four-electron oxygen evolving reaction is limited by proton adsorption and desorption, making its reaction kinetics sluggish, which poses a major challenge for catalyst design. Here, we present an unsaturated coordination interface by constructing a fast electron transfer channel between Cu₂V₂O₇ (CVO) and BiVO₄ (BVO). X-ray absorption spectroscopy (XAS) and theoretical calculations results confirm that CVO and BVO between interfaces are bonded by the way of unsaturated coordination oxygen (O_uc). The O_uc optimizes the O–O coupled energy barrier at the V active site and promotes the disconnection of O–H bond, which increases the photocurrent intensity of CVO by 6 times. In addition, due to the high electronegativity of the O_uc, the bonding energies of Bi–O and Cu–O at the interface are enhanced, resulting in the long-term stability of the photoanode during the water splitting. Finally, by integrating the working electrode with a polysilicon solar cell, we assembled a device that demonstrated exceptional catalytic performance, achieving a hydrogen production rate of 100.6 μmol·cm⁻², and maintaining a hydrogen-to-oxygen volume ratio of 2:1 after continuous operation for 4 h. This discovery aids in a deeper understanding of photoanode design and offers further insights for industrial applications.

Graphical abstract