Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability, high specific surface area, high porosity, and good chemical stability. Specifically, they exhibit distinctive optoelectronic features by integrating different molecular building blocks with appropriate links, constructing an π-conjugated system, or introducing electron donor–acceptor units into the conjugated framework. The reasonably adjusted band structure yields excellent photocatalytic activity of covalent organic framework materials. In this review, we comprehensively focus on applications of covalent organic framework materials as effective photocatalysts within the realm of hydrogen production, CO₂ reduction, pollutant degradation, organic conversion and other aspects. The discussion encompasses synthesis methods and reaction types of covalent organic frameworks. This review also discusses the state-of-the-art research progress, performance optimization strategies and the diverse manifestations of covalent organic framework materials used in photocatalysis. Finally, the main challenges and prospects aimed at further improving the photocatalytic performance of covalent organic frameworks are briefly proposed. By giving us a thorough understanding of the structural complexities of covalent organic frameworks and their essential role in photocatalytic processes, this effort advances our understanding and serves as a guide for the future design and development of novel covalent organic frameworks.

The efficient degradation of antibiotics in wastewater is critical for addressing global water pollution challenges. Herein, we report an Fe–Co dual-atom catalyst anchored on a nitrogen-doped carbon matrix (FeCo/NC), which demonstrates superior performance in peroxymonosulfate (PMS) activation and tetracycline (TC) degradation. This system achieves a remarkable TC removal efficiency of 91.2%, significantly outperforming single-atom catalysts. Mechanistic investigations reveal that FeCo/NC induces a unique spin-state reconstruction, optimizing its electronic structure and shifting the oxidative mechanism from a radical-driven pathway to a singlet oxygen (¹O₂)-dominated nonradical process. Theoretical insights from density functional theory (DFT) calculations confirm the preferred ¹O₂ generation pathway at FeCo active sites, with reduced energy barriers that enhance catalytic activity. Toxicological evaluations validate that TC degradation intermediates exhibit minimal ecological risks, reinforcing the environmental safety of this approach. The long-term stability of the FeCo/NC/PMS system was evaluated via a continuous-flow photocatalytic reactor. The above results reflect the superior catalytic activity and stability of the FeCo/NC/PMS system. This work establishes a paradigm for designing advanced dual-atom catalysts and provides critical insights for developing eco-friendly solutions to antibiotic-contaminated wastewater treatment.

To eradicate antibiotics from aqueous solution, cerium(Ce) doped ZnFe₂O₄ microspheres with different Ce mass ratios were prepared by a hydrothermal method and applied for the photocatalytic decomposition of tetracycline antibiotic. The results reveal that the introduction of Ce improves the charge separation for the photogenerated electron-hole pairs, which can be confirmed form the photocurrent spectra. The optimized sample ZnFe_1.96Ce_0.04O₄ shows a decomposition rate of 56.6% under simulated solar light within 40 min. The trapping experiments show that hydroxyl radical and superoxide radical are the main degrading species, directly involving in the decomposition of antibiotics. Moreover, the rate of hydrogen produced from water splitting photocatalyzed by ZnFe_1.96Ce_0.04O₄ reaches 230.4μmol/(g·h) under simulated solar light irradiation.