Metal–Organic Framework-Based Heterojunction Materials for Photocatalytic CO2 Reduction Reaction

Abstract

The escalating reliance on fossil fuels has exacerbated anthropogenic CO₂ emissions, driving global climate change and necessitating urgent strategies for carbon mitigation. Among emerging solutions, photocatalytic CO₂ reduction (CO₂RR) offers a dual benefit by converting CO₂ into value-added chemicals and renewable fuels using solar energy. However, the inherent thermodynamic stability of CO₂, particularly the high bond dissociation energy of the CO bond (805 kJ mol⁻¹), poses a significant challenge to efficient activation and selective conversion. Recent advances highlight metal–organic frameworks (MOFs) as promising photocatalysts due to their tunable structures, high surface areas, and semiconductor-like properties, which enable precise modulation of band structures, charge transport pathways, and active site distribution. Despite their potential, MOF-based systems face limitations such as restricted light absorption and rapid charge recombination. To address these challenges, the integration of MOFs with complementary materials to form heterojunctions has emerged as a key strategy, enhancing charge separation and catalytic selectivity. This review systematically examines recent progress in MOF-based heterojunction photocatalysts, focusing on structural design principles, mechanistic insights, and performance optimization. By analyzing structure–activity relationships and advanced regulation strategies, we highlight innovative approaches to improve efficiency, selectivity, and stability. Furthermore, we identify critical challenges, including scalability and long-term durability, and propose future directions to inform the optimization of novel photocatalytic systems.