Interfacial electronic mediation via POx bridges between BiVO4 and bimetallic metal-organic frameworks for boosting photoelectrochemical performance

Abstract

Effectively addressing the interfacial charge transfer between metal-organic framework (MOF) co-catalysts and photoanodes is crucial for enhancing photoelectrochemical (PEC) performance. In this work, an in-situ phosphorization strategy is innovatively proposed to construct oxidized phosphorus groups (PO_x) between a bimetallic MOF and BiVO₄ photoanode, without introducing an additional hole transport layer or impeding light absorption of the photoanode. This approach optimizes the electronic environment at the contact interface between the MOF and BiVO₄. Mediated by the PO_x groups, dual-path charge transfer channels (Bi-PO_x-Co and Ni-PO_x-V) are established. The electron-enriched Co sites serve as active centers for the oxygen evolution reaction (OER), while the electron-enriched V sites suppress metal dissolution. Consequently, the fabricated BVO/PO_x/CoNi-MOL photoanode achieves an ultra-high photocurrent density of 6.2 mA cm⁻² along with excellent long-term stability. The in-situ phosphorization approach presented here offers a powerful and generalizable methodology for enhancing interfacial charge transfer in composite photoelectrode systems.