Covalent Organic Frameworks Enable Sustainable Solar to Hydrogen Peroxide

As a chemical product with rapidly expanding demand in the field of modern energy and environmental applications, hydrogen peroxide (H2O2) has garnered widespread attention. However, the existing industrial production of H2O2 is plagued by high energy consumption, harmful waste emission, and severe safety issues, making it difficult to satisfy the environmental/economic production concept. Artificial photosynthesis offers a viable strategy for green and sustainable H2O2 production since it uses sunlight as an energy source to initiate the reaction of oxygen and water to produce H2O2. Among various photocatalysts, covalent organic frameworks (COFs), featuring highly ordered skeletons and well-defined active sites, have emerged as promising photocatalysts for H2O2 production. This review presents the nascent and burgeoning area of photocatalytic H2O2 production based on COFs. First, a brief overview of photocatalytic technology is provided, followed by a detailed introduction to the principles and evaluation of the photocatalytic H2O2 generation. Subsequently, the latest research progress on the judicious design of COFs for H2O2 photosynthesis is expounded, with a particular emphasis on manipulating the electronic structures and redox active sites. Finally, an outlook on the challenges and future opportunities is proposed, in the hope of stimulating further explorations of novel molecular-designed COFs for sustainable photosynthesis.