Interfacial P-O-Cu Bonds Drive Rapid Z-Scheme Charge Transfer for Efficient Photocatalytic O2 Evolution Synchronized with Cr(VI) Reduction

Addressing the challenges of energy production and environmental sustainability necessitates the development of advanced materials capable of facilitating both photocatalytic reduction and oxidation processes. Here, we report a Z-scheme Ag₃PO₄/CuBi₂O₄ heterojunction photocatalyst, which was fabricated via the in situ anisotropic growth of Ag₃PO₄ nanoparticles on the ends of CuBi₂O₄ microrods. The prepared heterojunction exhibits a low lattice mismatch (~3%) and features a covalently bonded interface, anchored by oxygen atoms, with the formation of P-O-Cu bonds. This interface synergizes with the built-in electric field to drive an efficient Z-scheme charge transfer mechanism, significantly enhancing the separation and migration of carriers. Furthermore, the interfacial chemical bonds induce electron redistribution that effectively weakens the Ag-O bond, thereby activating surface lattice oxygen. As a result, the photocatalyst shows remarkably improved performance for photocatalytic oxygen evolution synchronized with Cr(VI) reduction by enabling both the conventional adsorbate evolution mechanism and the lattice oxygen mechanism. This work provides critical insights into the design of efficient photocatalysts.