Synergistic spatial separation effect of internal electric field in ALD-generated BiFeO3/CuO@Co Z-type heterojunction for enhanced photocatalytic water oxidation

Abstract

Altering the electron distribution within a catalyst to manipulate internal charge migration pathways is an effective strategy for achieving high efficiency in carrier separation and migration, which is essential for the advancement of photocatalytic water oxidation technologies. We have employed atomic layer deposition (ALD) to construct a BiFeO₃/CuO (BFO/CuO) heterojunction with a specific CuO thickness, resulting in a Z-type junction (BFO/CuO50) characterized by a robust internal electric field. This junction facilitates the spatial separation of charge carriers, thereby enhancing their migration efficiency. Moreover, we introduced cobalt-based co-catalysts onto the BFO/CuO50 surface, leading to the creation of reactive centers that enrich holes, thus crafting a three-dimensional composite with superior carrier excitation and separation capabilities. The optimized catalyst, denoted as BFO/CuO50@Co_0.1%, demonstrated to produce oxygen at a rate of 1.53 mmol g⁻¹ h⁻¹ and remarkable stability. These findings provide the direction for research and design in the domain of photocatalytic oxygen evolution, offering a guidance for the development of complete water-splitting ferroelectric catalysts which enhance the generation and separation of photo-driven charge carriers.