Engineering MOF-based homojunction photocatalysts for sustainable energy and environment

Abstract

To overcome the critical challenges of interfacial lattice mismatch and low charge carrier separation efficiency inherent in conventional heterojunction systems, the development of homojunction photocatalysts has emerged as a promising alternative strategy. Metal–organic frameworks (MOFs), with their unique structural flexibility, tunable chemistry, and intrinsic semiconductor-like behavior, serve as an ideal platform for designing high-performance homojunction photocatalysts. This review offers a comprehensive and systematic overview of recent advancements in MOF-based homojunction photocatalysts, highlighting their innovative applications in sustainable energy production and environmental remediation. We first discuss construction strategies within pristine MOFs, including morphological engineering, hetero-phase engineering, and functional group modification, which enable precise control over electronic and interfacial properties. Next, we comprehensively analyze approaches for fabricating homojunctions from MOF derivatives, such as hetero-phase engineering, p–n junction engineering, morphological engineering, and doping engineering, highlighting their synergistic effects on charge separation, light absorption, and redox capacity while preserving structural integrity. The applications of these MOF-based homojunctions are then detailed, showcasing their exceptional performance in photocatalytic hydrogen evolution, CO₂ reduction, and pollutant elimination (e.g., Cr(VI), antibiotics, and volatile organic compounds (VOCs)), outperforming traditional heterojunction systems. Finally, we outline current challenges and future research directions, providing a roadmap for advancing MOF-based homojunction photocatalysts toward practical implementation. This review aims to expand new photocatalyst design ideas and provide a fundamental reference for the rational design of next-generation photocatalytic materials in the fields of energy and environmental sustainability.